Matronics Email Lists :: View topic - Strange Exp-Bus Problem

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Strange Exp-Bus Problem

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

peter(at)sportingaero.com
Guest

Posted: Sun Apr 27, 2008 12:34 pm Post subject: Strange Exp-Bus Problem

Hi,



The last few times I have flown I have had a few strange 'brown-outs'.

It is most noticeable over the intercom as a short kind of shhuukkk

sound. Occasionally the radio (KX-135A) re-cycles and goes through its

re-boot routine. Initially I thought it was the master solenoid, but

thinking some more, I concluded that if the master solenoid were to

momentarily lose contact then the alternator would hold everything up.

The interrupts are usually of very short duration, such that I don't

notice most of the services blink, or by the time I have looked inside

everything is back on again. Sometimes it happens once every 5 or 10

minutes, sometimes not for a half hour or more.



I have an Exp-Bus DC load centre - I know that there has been some less

than complementary comments here about these devices (and I would not

fit one to an airplane I built, but I bought this one and I don't want

to rip it out). I'm now thinking that I am suffering some strange very

intermittent failure of this device (that I can't reproduce on the

ground). 



Does anyone have any experience of the Exp-bus, or could suggest what

the fault might be?



Regards, Peter

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

hooverra(at)verizon.net
Guest

Posted: Sun Apr 27, 2008 4:56 pm Post subject: Strange Exp-Bus Problem

Peter,

	This is just a shot in the dark as I have no experience with the EXP

buss. I do have considerable experience with failed solder joints on PC

boards used in automotive applications. Look carefully at the solder joints

for a fracture either through the solder or at the junction of the solder

and heavy objects like relays. A magnifying glass helps. 



PS if this doesn't help on the EXP Buss keep it in mind for Bosch relays as

used on Volvo, Saab and many others. 10 minutes may save you enough to fill

a gas tank twice:) I've fixed flakey auto instrument panels this way also

and that's way more than a couple tanks of gas!!



Ralph & Laura Hoover

RV7A N527LR



--

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

mark(at)stratologic.net
Guest

Posted: Mon Apr 28, 2008 10:22 am Post subject: Strange Exp-Bus Problem

Hey Peter,  

   

Check the electrical system closely for wire connector rings of the incorrect size.  Eg. A too large ring over a connector stud.    

   

If the connector rings are bigger than the stud, over time they vibrate and the resulting residue makes a poor contact.  This will give you the exact fault you have…intermittent electrical faults.  

   

I would check all the contactors connections, alternator connectors, etc..anything with a big ring connector.  The culprit ring connector will look black when you take the nut off.  

   

Don’t ask how I know so much about this problem J  

   

Cheers,  

   

Mark.  

   

       [quote][b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum