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Yak-50 Electrical System Troubleshooting

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hairball192(at)yahoo.com
Guest

Posted: Mon Sep 11, 2006 10:38 am Post subject: Yak-50 Electrical System Troubleshooting

All:

 

I'd appreciate any assistance people are willing to

provide to assist me in troubleshooting my Yak-50's

electrical system.

 

Symptoms:

1.  Chronic problem of the left gear down indicator

light on or off-on when landing gear is up (with two

red up-and-locked lights also on) 



2.  Recently all annunciator lights (all four gear

indicators, generator, Over-G, chip, all cells on fuel

ladder) flashing on-off; Last flight all annunciator

lights were on and steady (same look as pushing the

press-to-test by the gear handle) 



3.  My electrical switches are labeled "Gear" and

"Inst"; The "Inst" switch controls the proper reading

of the fuel ladder (ie: it reads the correct amount of

fuel with this switch on), generator annunciator light

and engine instruments; The "gear" switch controls the

landing gear position indicator lights, all the light

cells on the fuel ladder (same as pushing the "k"

button to test the fuel indicator), the chip light and

the over-G light



In troubleshooting over the weekend, I performed the

following steps and got the following results:



1.  Turned on the following switches: Battery, inst,

and gear; All annunciator lights came on, I heard what

I think is some kind of electrical motor wind up for a

few seconds, then the "Gear" switch-breaker flipped

itself off and the associated annunciator lights went

off and the sound ceased 



2.  After cycling the switch a half dozen times with

my head under the panel to try to locate the noise,

the motor stopped coming on with the gear switch, but

it continues to break to the off position after

several seconds in the on position; There is about a 2

amp draw with the "gear" switch on as indicated by the

aircraft guage; The noise was coming from behind the

instrument panel, but I couldn't locate the component 



3.  There are two wires attached to the "gear" switch;

Removed the wire labeled 05-CW1 and turned on the

batt, inst and gear switches with the same result -- 2

amp draw and gear switch breaks to off after several

seconds 



4.  Removed the wire labeled 05-CW2-01 and turned on

the batt, inst and gear switches and now the gear

switch does not break, the elec system remains on; The

landing gear indicator lights, fuel ladder lights,

chip light, and over-G light do not illuminate (proper

fuel indication, generator light on, and engine

instruments are powered)  -- so the bad wire is this

one, I think 



5.  Re-installed both wires and verified that the

system fails in the same way as before 



6.  Friends manually held both landing gear position

squat switches in the "gear-up" position and turned

the electrical switches off with the same result --

Gear switch breaks to off after several seconds 



7.  Disconnected the left gear position squat switch

at the bus bar in the wing root by removing the lower

three of the four wires (I believe the top wire is for

pitot heat) and turned on the batt, inst and gear

switches -- GOT IT -- Same result as step 4 above --

Gear switch does not break, the elec system remains on

with a right gear down green light; I'm fuzzy on this

part, but I believe I did the push-to-test for the

annunciator lights and all worked EXCEPT the chip

light and over-G light 



8.  And then the plot thickens -- With the electrical

system on, manually depressed the RIGHT landing gear

squat switch -- The RIGHT gear down light went out and

the LEFT gear up light went on (hopefully a simple

crossed wire) AND got a 2.5 amp draw and the gear

switch broke to the off position after several seconds



Only two things scare me and both of them are

electricity, so I wouldn't have been able to do any of

this without the able help of some airport buds (Ken

and John).  I hope I've given those who know something

about this enough information to narrow things down

for me.  

 

I've got a couple of specific questions in addition to

the overall recommendations I hope will be

forthcoming:



- What electrical component do you think was making

the noise described in troubleshooting steps 1 and 2? 



- It looks like there are separate parts for the left

and right landing gear squat switches; Is that true? 



- From anyone out there has removed the entire Russian

electrical system and rewired new, how much time and

money did that take?  Do you have a parts list for the

new system? 



- Does anyone out there have an electrical diagram for

the Yak-50?



Many thanks in advance to everyone who's read this far

and to those who take the time to respond.

 

Regards,

Harry



__________________________________________________

viperdoc(at)mindspring.co
Guest

Posted: Mon Sep 11, 2006 12:10 pm Post subject: Yak-50 Electrical System Troubleshooting

Hitman,

I think Mark Bitterlich does. When I get home from the office today, I will

look at the CD that I have on 50 maintenance and let you know offline.

Doc

 	  Quote: 	
		   [Original Message]

 From: Harry Hirschman <hairball192(at)yahoo.com>

 To: Yaklist Yaklist <yak-list(at)matronics.com>

 Date: 9/11/2006 1:48:14 PM

 Subject: Yak-50 Electrical System Troubleshooting



 



 All:

  

 I'd appreciate any assistance people are willing to

 provide to assist me in troubleshooting my Yak-50's

 electrical system.

  

 Symptoms:

 1.  Chronic problem of the left gear down indicator

 light on or off-on when landing gear is up (with two

 red up-and-locked lights also on) 



 2.  Recently all annunciator lights (all four gear

 indicators, generator, Over-G, chip, all cells on fuel

 ladder) flashing on-off; Last flight all annunciator

 lights were on and steady (same look as pushing the

 press-to-test by the gear handle) 



 3.  My electrical switches are labeled "Gear" and

 "Inst"; The "Inst" switch controls the proper reading

 of the fuel ladder (ie: it reads the correct amount of

 fuel with this switch on), generator annunciator light

 and engine instruments; The "gear" switch controls the

 landing gear position indicator lights, all the light

 cells on the fuel ladder (same as pushing the "k"

 button to test the fuel indicator), the chip light and

 the over-G light



 In troubleshooting over the weekend, I performed the

 following steps and got the following results:



 1.  Turned on the following switches: Battery, inst,

 and gear; All annunciator lights came on, I heard what

 I think is some kind of electrical motor wind up for a

 few seconds, then the "Gear" switch-breaker flipped

 itself off and the associated annunciator lights went

 off and the sound ceased 



 2.  After cycling the switch a half dozen times with

 my head under the panel to try to locate the noise,

 the motor stopped coming on with the gear switch, but

 it continues to break to the off position after

 several seconds in the on position; There is about a 2

 amp draw with the "gear" switch on as indicated by the

 aircraft guage; The noise was coming from behind the

 instrument panel, but I couldn't locate the component 



 3.  There are two wires attached to the "gear" switch;

 Removed the wire labeled 05-CW1 and turned on the

 batt, inst and gear switches with the same result -- 2

 amp draw and gear switch breaks to off after several

 seconds 



 4.  Removed the wire labeled 05-CW2-01 and turned on

 the batt, inst and gear switches and now the gear

 switch does not break, the elec system remains on; The

 landing gear indicator lights, fuel ladder lights,

 chip light, and over-G light do not illuminate (proper

 fuel indication, generator light on, and engine

 instruments are powered)  -- so the bad wire is this

 one, I think 



 5.  Re-installed both wires and verified that the

 system fails in the same way as before 



 6.  Friends manually held both landing gear position

 squat switches in the "gear-up" position and turned

 the electrical switches off with the same result --

 Gear switch breaks to off after several seconds 



 7.  Disconnected the left gear position squat switch

 at the bus bar in the wing root by removing the lower

 three of the four wires (I believe the top wire is for

 pitot heat) and turned on the batt, inst and gear

 switches -- GOT IT -- Same result as step 4 above --

 Gear switch does not break, the elec system remains on

 with a right gear down green light; I'm fuzzy on this

 part, but I believe I did the push-to-test for the

 annunciator lights and all worked EXCEPT the chip

 light and over-G light 



 8.  And then the plot thickens -- With the electrical

 system on, manually depressed the RIGHT landing gear

 squat switch -- The RIGHT gear down light went out and

 the LEFT gear up light went on (hopefully a simple

 crossed wire) AND got a 2.5 amp draw and the gear

 switch broke to the off position after several seconds



 Only two things scare me and both of them are

 electricity, so I wouldn't have been able to do any of

 this without the able help of some airport buds (Ken

 and John).  I hope I've given those who know something

 about this enough information to narrow things down

 for me.  

  

 I've got a couple of specific questions in addition to

 the overall recommendations I hope will be

 forthcoming:



 - What electrical component do you think was making

 the noise described in troubleshooting steps 1 and 2? 



 - It looks like there are separate parts for the left

 and right landing gear squat switches; Is that true? 



 - From anyone out there has removed the entire Russian

 electrical system and rewired new, how much time and

 money did that take?  Do you have a parts list for the

 new system? 



 - Does anyone out there have an electrical diagram for

 the Yak-50?



 Many thanks in advance to everyone who's read this far

 and to those who take the time to respond.

  

 Regards,

 Harry



 __________________________________________________

Rob Rowe

Joined: 10 Jan 2006
Posts: 124
Location: Berkshire, UK

Posted: Mon Sep 11, 2006 3:41 pm Post subject: Re: Yak-50 Electrical System Troubleshooting

Hi Harry,



FWIW from what I know of the YAK-52 electrical schematics I'm hoping  may extrapolate to your YAK-50 diagnostics.



The breaker switches for the gear & instruments are probably both 5 Amps ... so I'm assuming when you're quoting a 2-3 Amp draw you're reading this verbatim from the ammeter gauge. If so then be aware that this gauge reads "x 10" ... in which case you're seeing 20-30 Amps being drawn which is why the breaker cuts out.



From your general description of numerous problems occuring  simultaneously I wonder if you have something loose in your relay box that holds the lamp test relay(s) ... causing shorts to various circuits ... so find the box labelled "РЕЛЕ ЩИТОК" or similar & take a look inside for anything loose, metallic & probably blackened!



Hope this helps.



Rob

mark.bitterlich(at)navy.m
Guest

Posted: Tue Sep 12, 2006 1:08 pm Post subject: Yak-50 Electrical System Troubleshooting

Harry, I do not have a 50 electrical diagram (Doc if you have one, I'd

dearly love to get a copy), but I have traced out a lot of it, and most

of what I have seen duplicates the 52 in many ways.  I am going to need

the full electrical diagram to help you out further, but I have a lot of

comments to make here.  Also, please excuse my lack of tact, I am an

EA-6B Avionics Tech Rep by profession and I work on problems like this

ALL the time.  There are a few general rules that you always go by when

dealing with this type of nonsense.  



A.  Always suspect what was last worked on as the FIRST place you should

look for a problem.  If human hands have recently been involved anywhere

near wiring, and you now have an electrical problem that you never had

before... GO WHERE PEOPLE RECENTLY PUT THEIR HANDS AND LOOK THERE FIRST.

You'd be amazed at how often that rule is ignored out of simple ego, but

boy is it accurate!  



B.  If you are dealing with a system of wires, switches, lights, etc.,

always suspect any part that moves, like switches, as being the first

thing you check for failure. 



C.  NEVER EVER reset a circuit breaker more than once if it pops.  You

NEVER, EVER EVER troubleshoot a problem like this by pulling this wire,

or that wire, and then turning on the breaker again to see if it pops.

There are many reasons for this, but the most obvious is that you can

easily end up starting an electrical fire, and please keep in mind where

the fuel tanks are in your YAK-50.  For example, let's say a wire was

arcing out against your fuel tank.  Not hard to imagine since it is only

inches away from your wiring.  Each time you reset that breaker you get

an ARC.  Eventually the arc actually cuts a hole in the tank and now you

have gas fumes adding into the mess.  Explosion, fire, you name it.  You

can also generate a wiring fire, even without gas involved.  Bottom

line, stop doing that and never do it again... Please.  Anyone that says

I am wrong in this regard is an idiot.... Avoid them.     



Ok.  So you now ask... How do I troubleshoot this problem WITHOUT doing

that?  The answer requires you to have a grasp of the basics of

electrically, which you admitted that you do not have, but here we go, I

am going to teach you one trick now and anyone else who bothers to read

this.  



You did exactly the right thing when you took the wires off the circuit

breaker/switch.  You need to get an electrical meter and learn how to

read DC VOLTS with it.  It's pretty easy.  Set it to DC VOLTS, hook the

black wire to aircraft ground (any good bonding point in the aircraft

itself to the frame) and then use the red wire to touch a wire and read

voltage.  Turn on your electrical master.. The one marked BATTERY.  Now

look at the switch going to the gear.  With the switch turned off, one

side will have 28 volts on it, and the other side will have NO volts on

it.  The side with NO volts on it will be the one we want to mess with

first.  In this case, you have already done that part... You have

located a wire that if you pull it off, it stops the problem.  Luckily

nothing that we know of blew up in the process.  God loves you.  



What you need to do now is to learn how to troubleshoot to the next

step.  One good way to accomplish this is by rigging the aircraft so

that it limits the current draw to this wire.  The wire that you found

is going to a short circuit, and that is why the breaker is popping.

You need to locate some 28 volt light bulbs.  If you do not have any, I

will send you some.  Let me know.  You get about a 25 watt bulb rated at

28 volts (again, I will be glad to give you as many as you need).  You

solder two wires to this light bulb.  Now, hook one wire of the bulb (it

does not matter which one) to the terminal on the switch.  Hook the

other wire soldered to the light bulb to the wire that you have hanging

that used to connect to the switch.  



Now when you turn on your switch, your light bulb will come on, because

you have a short to ground in the aircraft wiring SOMEPLACE.  But the

circuit breaker/switch will NOT blow anymore, because the light bulb

that you just installed in series between the wire you pulled off, and

the switch itself, will limit the current to ONE AMP (plus or minus a

tiny bit).  All the wiring and crap in the aircraft can handle one amp

with ease.  If you want to lower the amount of current, just use a

smaller bulb...  For example a 12 watt bulb would give you a maximum

current draw of about 1/2 amp.  Current in this case will be equal to

the wattage of the bulb divided by the voltage.  



You can now start trying to find the problem by tracing and removing

other wires, as you were doing before, or simply by jiggling things

around.  



Some might recommend that instead of doing it this way, you simply use

an OHM METER connected to your wire that you pulled OFF the switch.

This will also work if you know exactly what you are doing, but the

light bulb trick makes finding a problem like this easier and it is an

ACTIVE versus a PASSIVE check.  If the bulb is brightly lit, you have a

short circuit involved.  Which is of course what you DO have.  When the

bulb goes out, or gets very dim... You just located the problem.  



You need to be more detailed with your explanation if you could please.

There are NO SQUAT switches in the YAK-50.  A SQUAT switch is one that

closes when you LAND THE AIRPLANE and put weight on the landing gear.

The YAK-50 does not have anything like that.  



Instead there are FOUR switches that control the landing gear lights on

the 50.  One switch for each light on the dash.  There are two switches

on the left side, and two switches on the RIGHT side.   ONE SWITCH FOR

EACH LIGHT!   You are only seeing the switch back behind the gear

actuator where the wheels go into the hole.  There is ANOTHER switch

that is located underneath a panel right behind the gear leg itself.

The panel right behind that landing gear fiberglass shroud.



I do not know of any electrical motors behind the instrument panel.

There is of course the electrical inverter for the attitude indicator

(if you still have it installed) behind the seat.  At this point, I

would not waste a lot of time looking for the weird noise... Since you

already have enough other weird crap already happening.  



You took the fairings off the wing root(s) and have access to the wiring

connections going out to the pitot probe and the switches.  REMEMBER

AGAIN... Two switches on each landing gear!  Anyway, that is a good

thing.  You might want to do the same for the other side too, so that

you can access that wiring, but I suspect the wiring short circuit is

not out there.  



QUESTIONS: 



What happens in the cockpit when you leave the instrument breaker OFF

and just turn on the landing gear breaker?  

What happens when you turn on the instrument breaker and leave the

landing gear breaker off?  



REALLY NEED TO KNOW THE ABOVE ANSWERS.  



What is obvious here is that when you apply voltage to wire 05-cw2-01 by

connecting it to the switch and turning it on, the voltage through this

wire is shorting to some other WIRE that it should not be doing.  The

problem is that this wire is also obviously the main voltage feed for

the landing gear circuits.  The voltage on this wire feeds to all four

of the landing gear switches... The two UP switches and the two DOWN

switches.  Wires coming back from these switches then go to the light

bulbs in the cockpit themselves and make them come on.  So picture that

in your mind.... Voltage comes out this wire (the one hooked to the

switch), and someplace goes to a terminal board and splits to go out to

all four switches.  It then comes BACK from those switches and goes BACK

into the instrument panel and to the lights themselves.  



Next, consider that you have had a problem on the LEFT side of the

aircraft for quite some time.  This has been a case where the landing

gear DOWN switch has probably gone bad or is out of adjustment.  Again,

you need to locate that switch, because that is yet another problem,

probably not related to this current mess.  



The short circuit you are dealing with is probably NOT in the wings.

When you pressed the switch on the right landing gear, and then the

light for the left gear lit up, this is not a case of a wire switched

around, this is a case of some wires that are SHORTED TOGETHER.  



So some advice.  



When describing what switches you are pushing in the future, make sure

you name them correctly.  One is for right gear down and locked.  One is

for right gear UP and locked.  Same thing for the left side.  No squat

switches ok?  



It appears that the wire that is shorted is one of the wires coming BACK

from one of the switches TO the lights on the instrument panel.  One of

THOSE wires has shorted to another wire or wires causing all the other

lights to come on.  Most likely it is a short to the TEST SWITCH that

causes all those other lights to come on.  So to repeat, this is

probably a dead short between one of the wires coming back from the

landing gear position switches, that is shorted to the TEST switch

WIRING.  



To repeat again, the way I would try to find this would be to pull the

05-CW2-01 wire off the switch as you already had done.  The install the

28 volt light bulb with the wires connected to it in series.  It will

go: switch, wire, bulb, wire, then hooked to the 05-CW2-01 wire itself.

In SERIES.   You will then limit the current draw and will pose little

to zero risk of blowing anything up any further.  When you turn on the

switch, this light will come on brightly.  If you want, you can put

plenty of wire on the bulb and remote it out of the cockpit so it does

not get in the way.  Have someone watch this bulb like a hawk.  Now get

your hands back in the wiring and start moving wires and wire bundles

around... All over the place.  When you see that light bulb start

flickering wildly, you are on top of the problem.  



A complete wiring diagram will be really handy.  I do not have one.

HOWEVER... This is not a case of a failed component.  This is a case of

some wires shorting together that were never meant to be.  Wire

CHAFFING, or rubbing under a clamp, etc.  



There is a very VERY small chance of a relay failing internally ...

Literally falling apart inside, and shorting everything out that could

cause this.  This would be the light bulb TEST RELAY that is turned on

with the light test push button, and we would definitely need the

schematics to identify which relay this is.  It is also possible that

this relay got fried during this failure.  So other than wiring, this

would be the first component I would spot light for sure.  



Harry.. You're out on the west coast aren't you?  



Mark Bitterlich 

N50YK



P.s.  Rewiring the aircraft is a do-able thing, but man oh man, it would

cost a small fortune.  

--

viperdoc(at)mindspring.co
Guest

Posted: Tue Sep 12, 2006 4:15 pm Post subject: Yak-50 Electrical System Troubleshooting

Good discription Mark, I am not an electrician/avionics guy by any sense of

the word. Took in physics and remember a thimb full. I will send you the

wiring diagram I currently have courtesy of Tim Gagnon. Credit be given

where due. Send me a fax # offline and when I get back to the office

tomorrow.

Doc

 	  Quote: 	
		   [Original Message]

 From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E

<mark.bitterlich(at)navy.mil>.
	


 	  Quote: 	
		   To: <yak-list(at)matronics.com>

 Date: 9/12/2006 4:18:49 PM

 Subject: RE: Yak-50 Electrical System Troubleshooting



 

MALS-14 64E" <mark.bitterlich(at)navy.mil>
	


[quote]

  

 Harry, I do not have a 50 electrical diagram (Doc if you have one, I'd

 dearly love to get a copy), but I have traced out a lot of it, and most

 of what I have seen duplicates the 52 in many ways.  I am going to need

 the full electrical diagram to help you out further, but I have a lot of

 comments to make here.  Also, please excuse my lack of tact, I am an

 EA-6B Avionics Tech Rep by profession and I work on problems like this

 ALL the time.  There are a few general rules that you always go by when

 dealing with this type of nonsense.  



 A.  Always suspect what was last worked on as the FIRST place you should

 look for a problem.  If human hands have recently been involved anywhere

 near wiring, and you now have an electrical problem that you never had

 before... GO WHERE PEOPLE RECENTLY PUT THEIR HANDS AND LOOK THERE FIRST.

 You'd be amazed at how often that rule is ignored out of simple ego, but

 boy is it accurate!  



 B.  If you are dealing with a system of wires, switches, lights, etc.,

 always suspect any part that moves, like switches, as being the first

 thing you check for failure. 



 C.  NEVER EVER reset a circuit breaker more than once if it pops.  You

 NEVER, EVER EVER troubleshoot a problem like this by pulling this wire,

 or that wire, and then turning on the breaker again to see if it pops.

 There are many reasons for this, but the most obvious is that you can

 easily end up starting an electrical fire, and please keep in mind where

 the fuel tanks are in your YAK-50.  For example, let's say a wire was

 arcing out against your fuel tank.  Not hard to imagine since it is only

 inches away from your wiring.  Each time you reset that breaker you get

 an ARC.  Eventually the arc actually cuts a hole in the tank and now you

 have gas fumes adding into the mess.  Explosion, fire, you name it.  You

 can also generate a wiring fire, even without gas involved.  Bottom

 line, stop doing that and never do it again... Please.  Anyone that says

 I am wrong in this regard is an idiot.... Avoid them.     



 Ok.  So you now ask... How do I troubleshoot this problem WITHOUT doing

 that?  The answer requires you to have a grasp of the basics of

 electrically, which you admitted that you do not have, but here we go, I

 am going to teach you one trick now and anyone else who bothers to read

 this.  



 You did exactly the right thing when you took the wires off the circuit

 breaker/switch.  You need to get an electrical meter and learn how to

 read DC VOLTS with it.  It's pretty easy.  Set it to DC VOLTS, hook the

 black wire to aircraft ground (any good bonding point in the aircraft

 itself to the frame) and then use the red wire to touch a wire and read

 voltage.  Turn on your electrical master.. The one marked BATTERY.  Now

 look at the switch going to the gear.  With the switch turned off, one

 side will have 28 volts on it, and the other side will have NO volts on

 it.  The side with NO volts on it will be the one we want to mess with

 first.  In this case, you have already done that part... You have

 located a wire that if you pull it off, it stops the problem.  Luckily

 nothing that we know of blew up in the process.  God loves you.  



 What you need to do now is to learn how to troubleshoot to the next

 step.  One good way to accomplish this is by rigging the aircraft so

 that it limits the current draw to this wire.  The wire that you found

 is going to a short circuit, and that is why the breaker is popping.

 You need to locate some 28 volt light bulbs.  If you do not have any, I

 will send you some.  Let me know.  You get about a 25 watt bulb rated at

 28 volts (again, I will be glad to give you as many as you need).  You

 solder two wires to this light bulb.  Now, hook one wire of the bulb (it

 does not matter which one) to the terminal on the switch.  Hook the

 other wire soldered to the light bulb to the wire that you have hanging

 that used to connect to the switch.  



 Now when you turn on your switch, your light bulb will come on, because

 you have a short to ground in the aircraft wiring SOMEPLACE.  But the

 circuit breaker/switch will NOT blow anymore, because the light bulb

 that you just installed in series between the wire you pulled off, and

 the switch itself, will limit the current to ONE AMP (plus or minus a

 tiny bit).  All the wiring and crap in the aircraft can handle one amp

 with ease.  If you want to lower the amount of current, just use a

 smaller bulb...  For example a 12 watt bulb would give you a maximum

 current draw of about 1/2 amp.  Current in this case will be equal to

 the wattage of the bulb divided by the voltage.  



 You can now start trying to find the problem by tracing and removing

 other wires, as you were doing before, or simply by jiggling things

 around.  



 Some might recommend that instead of doing it this way, you simply use

 an OHM METER connected to your wire that you pulled OFF the switch.

 This will also work if you know exactly what you are doing, but the

 light bulb trick makes finding a problem like this easier and it is an

 ACTIVE versus a PASSIVE check.  If the bulb is brightly lit, you have a

 short circuit involved.  Which is of course what you DO have.  When the

 bulb goes out, or gets very dim... You just located the problem.  



 You need to be more detailed with your explanation if you could please.

 There are NO SQUAT switches in the YAK-50.  A SQUAT switch is one that

 closes when you LAND THE AIRPLANE and put weight on the landing gear.

 The YAK-50 does not have anything like that.  



 Instead there are FOUR switches that control the landing gear lights on

 the 50.  One switch for each light on the dash.  There are two switches

 on the left side, and two switches on the RIGHT side.   ONE SWITCH FOR

 EACH LIGHT!   You are only seeing the switch back behind the gear

 actuator where the wheels go into the hole.  There is ANOTHER switch

 that is located underneath a panel right behind the gear leg itself.

 The panel right behind that landing gear fiberglass shroud.



 I do not know of any electrical motors behind the instrument panel.

 There is of course the electrical inverter for the attitude indicator

 (if you still have it installed) behind the seat.  At this point, I

 would not waste a lot of time looking for the weird noise... Since you

 already have enough other weird crap already happening.  



 You took the fairings off the wing root(s) and have access to the wiring

 connections going out to the pitot probe and the switches.  REMEMBER

 AGAIN... Two switches on each landing gear!  Anyway, that is a good

 thing.  You might want to do the same for the other side too, so that

 you can access that wiring, but I suspect the wiring short circuit is

 not out there.  



 QUESTIONS: 



 What happens in the cockpit when you leave the instrument breaker OFF

 and just turn on the landing gear breaker?  

 What happens when you turn on the instrument breaker and leave the

 landing gear breaker off?  



 REALLY NEED TO KNOW THE ABOVE ANSWERS.  



 What is obvious here is that when you apply voltage to wire 05-cw2-01 by

 connecting it to the switch and turning it on, the voltage through this

 wire is shorting to some other WIRE that it should not be doing.  The

 problem is that this wire is also obviously the main voltage feed for

 the landing gear circuits.  The voltage on this wire feeds to all four

 of the landing gear switches... The two UP switches and the two DOWN

 switches.  Wires coming back from these switches then go to the light

 bulbs in the cockpit themselves and make them come on.  So picture that

 in your mind.... Voltage comes out this wire (the one hooked to the

 switch), and someplace goes to a terminal board and splits to go out to

 all four switches.  It then comes BACK from those switches and goes BACK

 into the instrument panel and to the lights themselves.  



 Next, consider that you have had a problem on the LEFT side of the

 aircraft for quite some time.  This has been a case where the landing

 gear DOWN switch has probably gone bad or is out of adjustment.  Again,

 you need to locate that switch, because that is yet another problem,

 probably not related to this current mess.  



 The short circuit you are dealing with is probably NOT in the wings.

 When you pressed the switch on the right landing gear, and then the

 light for the left gear lit up, this is not a case of a wire switched

 around, this is a case of some wires that are SHORTED TOGETHER.  



 So some advice.  



 When describing what switches you are pushing in the future, make sure

 you name them correctly.  One is for right gear down and locked.  One is

 for right gear UP and locked.  Same thing for the left side.  No squat

 switches ok?  



 It appears that the wire that is shorted is one of the wires coming BACK

 from one of the switches TO the lights on the instrument panel.  One of

 THOSE wires has shorted to another wire or wires causing all the other

 lights to come on.  Most likely it is a short to the TEST SWITCH that

 causes all those other lights to come on.  So to repeat, this is

 probably a dead short between one of the wires coming back from the

 landing gear position switches, that is shorted to the TEST switch

 WIRING.  



 To repeat again, the way I would try to find this would be to pull the

 05-CW2-01 wire off the switch as you already had done.  The install the

 28 volt light bulb with the wires connected to it in series.  It will

 go: switch, wire, bulb, wire, then hooked to the 05-CW2-01 wire itself.

 In SERIES.   You will then limit the current draw and will pose little

 to zero risk of blowing anything up any further.  When you turn on the

 switch, this light will come on brightly.  If you want, you can put

 plenty of wire on the bulb and remote it out of the cockpit so it does

 not get in the way.  Have someone watch this bulb like a hawk.  Now get

 your hands back in the wiring and start moving wires and wire bundles

 around... All over the place.  When you see that light bulb start

 flickering wildly, you are on top of the problem.  



 A complete wiring diagram will be really handy.  I do not have one.

 HOWEVER... This is not a case of a failed component.  This is a case of

 some wires shorting together that were never meant to be.  Wire

 CHAFFING, or rubbing under a clamp, etc.  



 There is a very VERY small chance of a relay failing internally ...

 Literally falling apart inside, and shorting everything out that could

 cause this.  This would be the light bulb TEST RELAY that is turned on

 with the light test push button, and we would definitely need the

 schematics to identify which relay this is.  It is also possible that

 this relay got fried during this failure.  So other than wiring, this

 would be the first component I would spot light for sure.  



 Harry.. You're out on the west coast aren't you?  



 Mark Bitterlich 

 N50YK



 P.s.  Rewiring the aircraft is a do-able thing, but man oh man, it would

 cost a small fortune.  

 --

netmaster15(at)juno.com
Guest

Posted: Wed Sep 13, 2006 8:10 pm Post subject: Yak-50 Electrical System Troubleshooting

Doc,

I would be most appreciative if you would fax me a wiring diagram of the electrical system. My fax is : 1 828 321 0878. Thankyou. 

Cliff



-- "Roger Kemp" <viperdoc(at)mindspring.com> wrote:




Good discription Mark, I am not an electrician/avionics guy by any sense of

the word. Took in physics and remember a thimb full. I will send you the

wiring diagram I currently have courtesy of Tim Gagnon. Credit be given

where due. Send me a fax # offline and when I get back to the office

tomorrow.

Doc

 	  Quote: 	
		   [Original Message]

 From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E

<mark.bitterlich(at)navy.mil>.
	


 	  Quote: 	
		   To: <yak-list(at)matronics.com>

 Date: 9/12/2006 4:18:49 PM

 Subject: RE: Yak-50 Electrical System Troubleshooting



 

MALS-14 64E" <mark.bitterlich(at)navy.mil>
	


[quote]

  

 Harry, I do not have a 50 electrical diagram (Doc if you have one, I'd

 dearly love to get a copy), but I have traced out a lot of it, and most

 of what I have seen duplicates the 52 in many ways.  I am going to need

 the full electrical diagram to help you out further, but I have a lot of

 comments to make here.  Also, please excuse my lack of tact, I am an

 EA-6B Avionics Tech Rep by profession and I work on problems like this

 ALL the time.  There are a few general rules that you always go by when

 dealing with this type of nonsense.  



 A.  Always suspect what was last worked on as the FIRST place you should

 look for a problem.  If human hands have recently been involved anywhere

 near wiring, and you now have an electrical problem that you never had

 before... GO WHERE PEOPLE RECENTLY PUT THEIR HANDS AND LOOK THERE FIRST.

 You'd be amazed at how often that rule is ignored out of simple ego, but

 boy is it accurate!  



 B.  If you are dealing with a system of wires, switches, lights, etc.,

 always suspect any part that moves, like switches, as being the first

 thing you check for failure. 



 C.  NEVER EVER reset a circuit breaker more than once if it pops.  You

 NEVER, EVER EVER troubleshoot a problem like this by pulling this wire,

 or that wire, and then turning on the breaker again to see if it pops.

 There are many reasons for this, but the most obvious is that you can

 easily end up starting an electrical fire, and please keep in mind where

 the fuel tanks are in your YAK-50.  For example, let's say a wire was

 arcing out against your fuel tank.  Not hard to imagine since it is only

 inches away from your wiring.  Each time you reset that breaker you get

 an ARC.  Eventually the arc actually cuts a hole in the tank and now you

 have gas fumes adding into the mess.  Explosion, fire, you name it.  You

 can also generate a wiring fire, even without gas involved.  Bottom

 line, stop doing that and never do it again... Please.  Anyone that says

 I am wrong in this regard is an idiot.... Avoid them.     



 Ok.  So you now ask... How do I troubleshoot this problem WITHOUT doing

 that?  The answer requires you to have a grasp of the basics of

 electrically, which you admitted that you do not have, but here we go, I

 am going to teach you one trick now and anyone else who bothers to read

 this.  



 You did exactly the right thing when you took the wires off the circuit

 breaker/switch.  You need to get an electrical meter and learn how to

 read DC VOLTS with it.  It's pretty easy.  Set it to DC VOLTS, hook the

 black wire to aircraft ground (any good bonding point in the aircraft

 itself to the frame) and then use the red wire to touch a wire and read

 voltage.  Turn on your electrical master.. The one marked BATTERY.  Now

 look at the switch going to the gear.  With the switch turned off, one

 side will have 28 volts on it, and the other side will have NO volts on

 it.  The side with NO volts on it will be the one we want to mess with

 first.  In this case, you have already done that part... You have

 located a wire that if you pull it off, it stops the problem.  Luckily

 nothing that we know of blew up in the process.  God loves you.  



 What you need to do now is to learn how to troubleshoot to the next

 step.  One good way to accomplish this is by rigging the aircraft so

 that it limits the current draw to this wire.  The wire that you found

 is going to a short circuit, and that is why the breaker is popping.

 You need to locate some 28 volt light bulbs.  If you do not have any, I

 will send you some.  Let me know.  You get about a 25 watt bulb rated at

 28 volts (again, I will be glad to give you as many as you need).  You

 solder two wires to this light bulb.  Now, hook one wire of the bulb (it

 does not matter which one) to the terminal on the switch.  Hook the

 other wire soldered to the light bulb to the wire that you have hanging

 that used to connect to the switch.  



 Now when you turn on your switch, your light bulb will come on, because

 you have a short to ground in the aircraft wiring SOMEPLACE.  But the

 circuit breaker/switch will NOT blow anymore, because the light bulb

 that you just installed in series between the wire you pulled off, and

 the switch itself, will limit the current to ONE AMP (plus or minus a

 tiny bit).  All the wiring and crap in the aircraft can handle one amp

 with ease.  If you want to lower the amount of current, just use a

 smaller bulb...  For example a 12 watt bulb would give you a maximum

 current draw of about 1/2 amp.  Current in this case will be equal to

 the wattage of the bulb divided by the voltage.  



 You can now start trying to find the problem by tracing and removing

 other wires, as you were doing before, or simply by jiggling things

 around.  



 Some might recommend that instead of doing it this way, you simply use

 an OHM METER connected to your wire that you pulled OFF the switch.

 This will also work if you know exactly what you are doing, but the

 light bulb trick makes finding a problem like this easier and it is an

 ACTIVE versus a PASSIVE check.  If the bulb is brightly lit, you have a

 short circuit involved.  Which is of course what you DO have.  When the

 bulb goes out, or gets very dim... You just located the problem.  



 You need to be more detailed with your explanation if you could please

viperdoc(at)mindspring.co
Guest

Posted: Thu Sep 14, 2006 8:16 am Post subject: Yak-50 Electrical System Troubleshooting

Cliff,

 Here is a emial version that is the same as the hardcopy that I have. Hope it helps.

 Doc

  

 



  

 [quote] ---

Yak-50_Electrical_Sys.doc

Description:

Download

Filename:

Yak-50_Electrical_Sys.doc

Filesize:

62 KB

Downloaded:

442 Time(s)

Mike Bell

Joined: 10 Jan 2006
Posts: 51

Posted: Thu Sep 14, 2006 8:33 am Post subject: Re: Yak-50 Electrical System Troubleshooting

Damn, I'm glad Bitterlich works for OUR navy.

_________________
Mike Bell
Elk Grove, CA
avbell2(at)comcastdotnet

viperdoc(at)mindspring.co
Guest

Posted: Thu Sep 14, 2006 9:09 am Post subject: Yak-50 Electrical System Troubleshooting

Amen brother...glad he has such a grasp on the electrical systems of YAK's

also!

Doc

 	  Quote: 	
		   [Original Message]

 From: Mike Bell <yakflyr(at)comcast.net>

 To: <yak-list(at)matronics.com>

 Date: 9/14/2006 11:50:11 AM

 Subject: Re: Yak-50 Electrical System Troubleshooting



 



 Damn, I'm glad Bitterlich works for OUR navy.



 --------

 Mike Bell

 Yak 52

 Elk Grove, CA

 yakflyr(at)comcastdotnet





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=61600#61600

mark.bitterlich(at)navy.m
Guest

Posted: Thu Sep 14, 2006 2:29 pm Post subject: Yak-50 Electrical System Troubleshooting

Nice thing to say Mike, thanks.  (!!!)  



Mark

 



--

Rob Rowe

Joined: 10 Jan 2006
Posts: 124
Location: Berkshire, UK

Posted: Fri Sep 15, 2006 10:50 am Post subject: Re: Yak-50 Electrical System Troubleshooting

Hi Harry



First off I'd like to whole heartedly endorse Mark B's excellent advice on fault finding ... if you're uncertain of what you're doing then find someone qualified.



However they will probably find a set of accurate circuit drawings invaluable ... so I did a a little research into YAK-50s, courtesy of Russian Engineering who are only a half hour drive away, which highlighted the following;



- real-world feedback suggests YAK-50 electrics vary in detail from machine to machine & the schematics suggest an evolution of the DC power management in particular. I think the DC power diagram kindly supplied by Doc is "early" in that there does not appear to be any over-voltage protection [OVP] unit & the "controller RK-1500R" / "filter SF-3000R" are not types fitted to other YAK52/55s or SUs ... AFAIK). Doc - does your documentation have any date info?



- schematics dated 1979 show DC power components identical to a YAK-52 with an A3P-1MB OVP unit (assume as -52s went into production they started to standardise the fit)



- schematics dated 1982 show an A3P-A2 OVP the same as contemporary YAK/SUs (complete with hand drawn amendments!)



I d like to have copies of these schematics made (with RE's permission) ... the challenge lies in that they're probably 3rd imprints already & they're 2m x lm sheets ... so difficult to scan or photograph, let alone make legible.



So ... before looking into this further what's the full construction number of your -50 Harry?



Cheers, Rob

Scooter

Joined: 10 Jan 2006
Posts: 155

Posted: Fri Sep 15, 2006 11:46 am Post subject: Re: Yak-50 Electrical System Troubleshooting

Harry,



Could you clarify steps 6 through 8 again.  I think the Yak-52 has two switches per gear leg (gear up and gear down...  i think).  Does the 50 have a single switch?  Also, what is your current draw before you get the short?



Is this correct:

6. Left Gear Up/Right Gear Up - short

7. Left Gear Disconnected/Right Gear Up - no short

8. Left Gear Disconnected/Right Gear Down - short

"6. Friends manually held both landing gear position

squat switches in the "gear-up" position and turned

the electrical switches off with the same result --

Gear switch breaks to off after several seconds



7. Disconnected the left gear position squat switch

at the bus bar in the wing root by removing the lower

three of the four wires (I believe the top wire is for

pitot heat) and turned on the batt, inst and gear

switches -- GOT IT -- Same result as step 4 above --

Gear switch does not break, the elec system remains on

with a right gear down green light; I'm fuzzy on this

part, but I believe I did the push-to-test for the

annunciator lights and all worked EXCEPT the chip

light and over-G light



8. And then the plot thickens -- With the electrical

system on, manually depressed the RIGHT landing gear

squat switch -- The RIGHT gear down light went out and

the LEFT gear up light went on (hopefully a simple

crossed wire) AND got a 2.5 amp draw and the gear

switch broke to the off position after several seconds "

Rob Rowe

Joined: 10 Jan 2006
Posts: 124
Location: Berkshire, UK

Posted: Fri Sep 15, 2006 5:52 pm Post subject: Re: Yak-50 Electrical System Troubleshooting

Hi Harry,



I've annotated the attached PDF file from a photo of the YAK-50 gear & instruments circuits, as per the 01.10.1982 schematic.



The wiring nomenclature does not tie up with your description of the gear switch wires ... but most of the symptoms you described (save for the inverter turning on) suggest the lamp test relay"C10" is worth investigation by a qualified engineer.



A brief word of caution ... my experience of YAK wiring diagrams is that occasionally they contain typos and/or small wiring anomalies ... another reason to seek professional assistance with fault finding.



This schematic has such an anomaly on the far right hand side marked with the hatched red line & query mark ... don't think this is significant with your issues, but worth noting.



Cheers, Rob

YAK-50 Electrical Circuits.pdf

Description:

Download

Filename:

YAK-50 Electrical Circuits.pdf

Filesize:

550.58 KB

Downloaded:

527 Time(s)

viperdoc(at)mindspring.co
Guest

Posted: Fri Sep 15, 2006 6:14 pm Post subject: Yak-50 Electrical System Troubleshooting

Rob,

There is not a date on the manual. I have another question. As I rotated

today, my Airspeed went to 0. My altimeter worked fine. I have a Dynon

hooked in series with the Russian Airspeed indicator. The Dynon went to 0

also. Landed using A/S from the GPS. Works!

Plan to pull the rubber hose of the A/S indicator at the T fitting to Dynon

and blow high press back through the system. Before I do that, I am going

to drop the inspection panel in the left wing root and drain any water out

of the system if any is in there? Any other suggestions?

Doc

 	  Quote: 	
		   [Original Message]

 From: Rob Rowe <yak-list(at)robrowe.plus.com>

 To: <yak-list(at)matronics.com>

 Date: 9/15/2006 2:17:03 PM

 Subject: Re: Yak-50 Electrical System Troubleshooting



 



 Hi Harry



 First off I'd like to whole heartedly endorse Mark B's excellent advice

on fault finding ... if you're uncertain of what you're doing then find
	


someone qualified.

 	  Quote: 	
		  

 However they will probably find a set of accurate circuit drawings

invaluable ... so I did a a little research into YAK-50s, courtesy of
	


Russian Engineering who are only a half hour drive away, which highlighted

the following;

 	  Quote: 	
		  

 - real-world feedback suggests YAK-50 electrics vary in detail from

machine to machine & the schematics suggest an evolution of the DC power
	


management in particular. I think the DC power diagram kindly supplied by

Doc is "early" in that there does not appear to be any over-voltage

protection [OVP] unit & the "controller RK-1500R" / "filter SF-3000R" are

not types fitted to other YAK52/55s or SUs ... AFAIK). Doc - does your

documentation have any date info?

 	  Quote: 	
		  

 - schematics dated 1979 show DC power components identical to a YAK-52

with an A3P-1MB OVP unit (assume as -52s went into production they started
	


to standardise the fit)

 	  Quote: 	
		  

 - schematics dated 1982 show an A3P-A2 OVP the same as contemporary

YAK/SUs (complete with hand drawn amendments!)
	


 	  Quote: 	
		  

 I d like to have copies of these schematics made (with RE's permission)

.. the challenge lies in that they're probably 3rd imprints already &
	


they're 2m x lm sheets ... so difficult to scan or photograph, let alone

make legible.

 	  Quote: 	
		  

 So ... before looking into this further what's the full construction

number of your -50 Harry?
	


 	  Quote: 	
		  

 Cheers, Rob





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=61838#61838

viperdoc(at)mindspring.co
Guest

Posted: Fri Sep 15, 2006 6:15 pm Post subject: Yak-50 Electrical System Troubleshooting

Rob,

Can you forward a cc of the wiring diagram also. My 50 is a 78 model though.

Doc

 	  Quote: 	
		   [Original Message]

 From: Rob Rowe <yak-list(at)robrowe.plus.com>

 To: <yak-list(at)matronics.com>

 Date: 9/15/2006 9:00:47 PM

 Subject: Re: Yak-50 Electrical System Troubleshooting



 



 Hi Harry,



 I've annotated the attached PDF file from a photo of the YAK-50 gear &

instruments circuits, as per the 01.10.1982 schematic.
	


 	  Quote: 	
		  

 The wiring nomenclature does not tie up with your description of the gear

switch wires ... but most of the symptoms you described (save for the
	


inverter turning on) suggest the lamp test relay"C10" is worth

investigation by a qualified engineer.

 	  Quote: 	
		  

 A brief word of caution ... my experience of YAK wiring diagrams is that

occasionally they contain typos and/or small wiring anomalies ... another
	


reason to seek professional assistance with fault finding.

 	  Quote: 	
		  

 This schematic has such an anomaly on the far right hand side marked with

the hatched red line & query mark ... don't think this is significant with
	


your issues, but worth noting.

 	  Quote: 	
		  

 Cheers, Rob





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=61891#61891





 Attachments: 



 http://forums.matronics.com//files/yak_50_electrical_circuits_151.pdf

Rob Rowe

Joined: 10 Jan 2006
Posts: 124
Location: Berkshire, UK

Posted: Fri Sep 15, 2006 6:40 pm Post subject: Re: Yak-50 Electrical System Troubleshooting

Hi Doc,



 	  viperdoc(at)mindspring.co wrote: 	
		  

 As I rotated today, my Airspeed went to 0. My altimeter worked fine.

	




FWIW - looks like your static source is ok, but your dynamic feed is blocked / open to atmos ... given you've recently installed the Dynon guess that would be a good place to start checking the plumbing. 



Careful with blowing high pressure into the either the static or dynamic lines (especially dynamic) without first double checking the instruments are disconnected ... could be expensive.



Re YAK-50 schematics - will email you the file shortly



Cheers, Rob

viperdoc(at)mindspring.co
Guest

Posted: Fri Sep 15, 2006 7:54 pm Post subject: Yak-50 Electrical System Troubleshooting

Thanks Rob. I plan to disconnect the dynamic (impact) line proximal to the

Dynon and the RU A/S indicator. That way they will be isolated from any

pressure applied to the impact line.

Doc

 	  Quote: 	
		   [Original Message]

 From: Rob Rowe <yak-list(at)robrowe.plus.com>

 To: <yak-list(at)matronics.com>

 Date: 9/15/2006 9:48:54 PM

 Subject: Re: Yak-50 Electrical System Troubleshooting

 Hi Doc,

 viperdoc(at)mindspring.co wrote:

 > 

 >  As I rotated today, my Airspeed went to 0. My altimeter worked fine.

 > 

 FWIW - looks like your static source is ok, but your dynamic feed is

blocked / open to atmos ... given you've recently installed the Dynon guess

that would be a good place to start checking the plumbing. 

 	  Quote: 	

 Careful with blowing high pressure into the either the static or dynamic

lines (especially dynamic) without first double checking the instruments

are disconnected ... could be expensive.

 	  Quote: 	

 Re YAK-50 schematics - will email you the file shortly

 Cheers, Rob

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=61897#61897

netmaster15(at)juno.com
Guest

Posted: Mon Sep 18, 2006 6:56 pm Post subject: Yak-50 Electrical System Troubleshooting

Doc,

Schematic received,  excellent, thanks very much.

Cliff



-- "Roger Kemp" <viperdoc(at)mindspring.com> wrote:



Cliff,Here is a emial version that is the same as the hardcopy that I have. Hope it helps.Doc  ---

viperdoc(at)mindspring.co
Guest

Posted: Tue Sep 19, 2006 4:19 am Post subject: Yak-50 Electrical System Troubleshooting

Cliff,

 From talking to Rob Kent, it is not complete. Seems our aircraft were kind of hand built and each one was somewhat different in each way. Later today, I will try to get you what he sent me in addition to what I had.

 Doc

  

 



  

 [quote] ---

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