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dan(at)azshowersolutions.
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 Posted: Wed Jun 13, 2012 9:12 am Post subject: SL-40 |
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Just when I thought I was out of the woods, an ole nemesis returns. As I mentioned in the last post, my noise going into intercom was canceled by an in-line audio suppressor.
Right after I did a run-up today getting ready to take off, I taxied to the hold-short line and called the tower. I lost my radio. I got back to the hanger to find for the second time I blew the 5 A fuse. The last time this happened was 11 to 12 hours ago. The SL-40 is wired to the E-Bus. I am of course concerned as to why this is happening, but know it could be a tough one to nail down. My thoughts have led me to try running power from the main bus but also using a DPDT switch to be able to flip the power to the radio via the
E-bus should it go south again. Any other ideas are welcome.
Dan B
[quote][b]
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Bill Schlatterer
Joined: 09 Jan 2006
Posts: 195
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| Posted: Wed Jun 13, 2012 10:17 am Post subject: SL-40 |
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Dan just curious, when you say lost … does that mean no power at all or no transmit/receive power? Maybe only on the 430 but it seems like there are two fuses. My SL40 just quit passing any audio to the headphones but still appears to indicate RX/TX as if power is applied and it is working.
Bill S
RV7a
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 12:09 PM
To: aeroelectric-list(at)matronics.com
Subject: SL-40
Just when I thought I was out of the woods, an ole nemesis returns. As I mentioned in the last post, my noise going into intercom was canceled by an in-line audio suppressor.
Right after I did a run-up today getting ready to take off, I taxied to the hold-short line and called the tower. I lost my radio. I got back to the hanger to find for the second time I blew the 5 A fuse. The last time this happened was 11 to 12 hours ago. The SL-40 is wired to the E-Bus. I am of course concerned as to why this is happening, but know it could be a tough one to nail down. My thoughts have led me to try running power from the main bus but also using a DPDT switch to be able to flip the power to the radio via the
E-bus should it go south again. Any other ideas are welcome.
Dan B
| Quote: | | http://www.matronics.com/Navigator?AeroElectric-List |
01234567
[quote][b]
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dan(at)azshowersolutions.
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| Posted: Wed Jun 13, 2012 10:33 am Post subject: SL-40 |
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Bill, yes, no power at all. The radio just went dead as it blew the 5A fuse at the E-bus. I looked up the SL-40 install manual and the unit does have a 7A internal fuse, but they do recommend the power in to be fused / breaker'd at no greater than 5A. It does not make much sense to me for this to happen every 10 to 15 hours.
Dan
From: Bill Schlatterer <billschlatterer(at)sbcglobal.net>
To: aeroelectric-list(at)matronics.com
Sent: Wednesday, June 13, 2012 11:15 AM
Subject: RE: SL-40
Dan just curious, when you say lost … does that mean no power at all or no transmit/receive power? Maybe only on the 430 but it seems like there are two fuses. My SL40 just quit passing any audio to the headphones but still appears to indicate RX/TX as if power is applied and it is working.
Bill S
RV7a
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 12:09 PM
To: aeroelectric-list(at)matronics.com
Subject: SL-40
Just when I thought I was out of the woods, an ole nemesis returns. As I mentioned in the last post, my noise going into intercom was canceled by an in-line audio suppressor.
Right after I did a run-up today getting ready to take off, I taxied to the hold-short line and called the tower. I lost my radio. I got back to the hanger to find for the second time I blew the 5 A fuse. The last time this happened was 11 to 12 hours ago. The SL-40 is wired to the E-Bus. I am of course concerned as to why this is happening, but know it could be a tough one to nail down. My thoughts have led me to try running power from the main bus but also using a DPDT switch to be able to flip the power to the radio via the
E-bus should it go south again. Any other ideas are welcome.
Dan B
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01234567
8
[quote][b]
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fvalarm(at)rapidnet.net
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| Posted: Wed Jun 13, 2012 10:51 am Post subject: SL-40 |
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If it was me, I would change to the next larger fuse size (7.5amp). Transmitting is not a sustained electrical condition. The fuse is to protect the wire between the fuse and the radio. You may consider metering the actual draw when transmitting for interest sake. You may find that the draw is right close to 5 amps, causing the "nuisance" trips.
If the radio requires a certain amount of electrical power, and the voltage supplied by the ebus is slightly lower due to the diode, then the current draw has to rise slightly to compensate. Perhaps this is causing a slightly higher draw (amps) when operating on the ebus as compared to the main bus..
My opinions only.
Bevan
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Bill Schlatterer
Sent: Wednesday, June 13, 2012 11:16 AM
To: aeroelectric-list(at)matronics.com
Subject: RE: AeroElectric-List: SL-40
Dan just curious, when you say lost … does that mean no power at all or no transmit/receive power? Maybe only on the 430 but it seems like there are two fuses. My SL40 just quit passing any audio to the headphones but still appears to indicate RX/TX as if power is applied and it is working.
Bill S
RV7a
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 12:09 PM
To: aeroelectric-list(at)matronics.com
Subject: AeroElectric-List: SL-40
Just when I thought I was out of the woods, an ole nemesis returns. As I mentioned in the last post, my noise going into intercom was canceled by an in-line audio suppressor.
Right after I did a run-up today getting ready to take off, I taxied to the hold-short line and called the tower. I lost my radio. I got back to the hanger to find for the second time I blew the 5 A fuse. The last time this happened was 11 to 12 hours ago. The SL-40 is wired to the E-Bus. I am of course concerned as to why this is happening, but know it could be a tough one to nail down. My thoughts have led me to try running power from the main bus but also using a DPDT switch to be able to flip the power to the radio via the
E-bus should it go south again. Any other ideas are welcome.
Dan B
| Quote: | | http://www.matronics.com/Navigator?AeroElectric-List |
01234567
8 [quote][b]
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dan(at)azshowersolutions.
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| Posted: Wed Jun 13, 2012 11:09 am Post subject: SL-40 |
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Bevan,
That is good logic in reference to the supplied voltage being a bit lower on the E-bus and kicking up the current. My D-100 is hooked up to the Main bus and my EIS (engine monitor) is on the the E bus. There is consistently about 1.5V lower being showed on the E-bus. I won't rule out the thought of the 7.5A fuse at a later date. I think I will see what happens changing over to the main bus.
Thank you for your input.
Dan
From: B Tomm <fvalarm(at)rapidnet.net>
To: aeroelectric-list(at)matronics.com
Sent: Wednesday, June 13, 2012 11:50 AM
Subject: RE: AeroElectric-List: SL-40
_filtered #yiv1421591727 { font-family:Calibri;} _filtered #yiv1421591727 { font-family:Tahoma;} _filtered #yiv1421591727 { font-family:Bookman Old Style;} _filtered #yiv1421591727 { font-family:Consolas;} _filtered #yiv1421591727 {margin:1.0in 1.0in 1.0in 1.0in;} #yiv1421591727 P.yiv1421591727MsoNormal { MARGIN:0in 0in 0pt;FONT-FAMILY:"serif";FONT-SIZE:12pt;} #yiv1421591727 LI.yiv1421591727MsoNormal { MARGIN:0in 0in 0pt;FONT-FAMILY:"serif";FONT-SIZE:12pt;} #yiv1421591727 DIV.yiv1421591727MsoNormal { MARGIN:0in 0in 0pt;FONT-FAMILY:"serif";FONT-SIZE:12pt;} #yiv1421591727 A:link { COLOR:blue;TEXT-DECORATION:underline;} #yiv1421591727 SPAN.yiv1421591727MsoHyperlink { COLOR:blue;TEXT-DECORATION:underline;} #yiv1421591727 A:visited { COLOR:purple;TEXT-DECORATION:underline;} #yiv1421591727 SPAN.yiv1421591727MsoHyperlinkFollowed { COLOR:purple;TEXT-DECORATION:underline;} #yiv1421591727 PRE { MARGIN:0in 0in 0pt;FONT-FAMILY:"Courier New";FONT-SIZE:10pt;} #yiv1421591727 SPAN.yiv1421591727HTMLPreformattedChar { FONT-FAMILY:"serif";} #yiv1421591727 SPAN.yiv1421591727EmailStyle19 { FONT-FAMILY:"sans-serif";COLOR:#1f497d;} #yiv1421591727 .yiv1421591727MsoChpDefault { FONT-SIZE:10pt;} #yiv1421591727 DIV.yiv1421591727WordSection1 { } If it was me, I would change to the next larger fuse size (7.5amp). Transmitting is not a sustained electrical condition. The fuse is to protect the wire between the fuse and the radio. You may consider metering the actual draw when transmitting for interest sake. You may find that the draw is right close to 5 amps, causing the "nuisance" trips.
If the radio requires a certain amount of electrical power, and the voltage supplied by the ebus is slightly lower due to the diode, then the current draw has to rise slightly to compensate. Perhaps this is causing a slightly higher draw (amps) when operating on the ebus as compared to the main bus..
My opinions only.
Bevan
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Bill Schlatterer
Sent: Wednesday, June 13, 2012 11:16 AM
To: aeroelectric-list(at)matronics.com
Subject: RE: SL-40
Dan just curious, when you say lost … does that mean no power at all or no transmit/receive power? Maybe only on the 430 but it seems like there are two fuses. My SL40 just quit passing any audio to the headphones but still appears to indicate RX/TX as if power is applied and it is working.
Bill S
RV7a
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 12:09 PM
To: aeroelectric-list(at)matronics.com
Subject: AeroElectric-List: SL-40
Just when I thought I was out of the woods, an ole nemesis returns. As I mentioned in the last post, my noise going into intercom was canceled by an in-line audio suppressor.
Right after I did a run-up today getting ready to take off, I taxied to the hold-short line and called the tower. I lost my radio. I got back to the hanger to find for the second time I blew the 5 A fuse. The last time this happened was 11 to 12 hours ago. The SL-40 is wired to the E-Bus. I am of course concerned as to why this is happening, but know it could be a tough one to nail down. My thoughts have led me to try running power from the main bus but also using a DPDT switch to be able to flip the power to the radio via the
E-bus should it go south again. Any other ideas are welcome.
Dan B
| Quote: | | http://www.matronics.com/Navigator?AeroElectric-List |
01234567
8 9
[quote][b]
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JohnInReno
Joined: 08 Sep 2007
Posts: 150
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| Posted: Wed Jun 13, 2012 1:45 pm Post subject: SL-40 |
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Probably way off base and a shot in the dark, but I discovered that it is easy to blow the radio fuse if the APRS transmitter broadcasts its periodic packet at the same time I press the transmit button. Separating the antennas solved the problem.
john
On 6/13/2012 10:08 AM, Dan Billingsley wrote: [quote] Just when I thought I was out of the woods, an ole nemesis returns. As I mentioned in the last post, my noise going into intercom was canceled by an in-line audio suppressor.
Right after I did a run-up today getting ready to take off, I taxied to the hold-short line and called the tower. I lost my radio. I got back to the hanger to find for the second time I blew the 5 A fuse. The last time this happened was 11 to 12 hours ago. The SL-40 is wired to the E-Bus. I am of course concerned as to why this is happening, but know it could be a tough one to nail down. My thoughts have led me to try running power from the main bus but also using a DPDT switch to be able to flip the power to the radio via the
E-bus should it go south again. Any other ideas are welcome.
Dan B
[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 |
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_________________
John Morgensen
RV-9A - Born on July 3, 2013
RV4 - for sale |
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ceengland(at)bellsouth.ne
Guest
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| Posted: Wed Jun 13, 2012 4:18 pm Post subject: SL-40 |
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The 'low voltage=high current' thing works for AC induction motors, but I wouldn't bet too heavily on it being the problem in a DC circuit. If you look at the volts/ohms/amps formulas, you can see why.
One thing that *can* happen is the fuse will get hot if there's a poor connection anywhere in the neighborhood: wire to terminal, terminal to fuse, and back again on the other side of the fuse. Think resistance heater. If it gets hot, it's weaker & vibration will increase the odds of mechanical failure of the fuse link itself. Is it a glass fuse, or one of the newer automotive blade type fuses? (Blade fuses should be somewhat less susceptible to the high resistance issue.)
Can you monitor voltage at the power terminal of the radio, & watch the voltage when you key the mic & actually transmit? If it drops noticeably, you've got high resistance somewhere in the circuit, & the fuse would be my 1st stop, especially if it's the old glass variety.
Charlie
On 06/13/2012 02:08 PM, Dan Billingsley wrote: [quote] Bevan,
That is good logic in reference to the supplied voltage being a bit lower on the E-bus and kicking up the current. My D-100 is hooked up to the Main bus and my EIS (engine monitor) is on the the E bus. There is consistently about 1.5V lower being showed on the E-bus. I won't rule out the thought of the 7.5A fuse at a later date. I think I will see what happens changing over to the main bus.
Thank you for your input.
Dan
From: B Tomm <fvalarm(at)rapidnet.net> (fvalarm(at)rapidnet.net)
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Sent: Wednesday, June 13, 2012 11:50 AM
Subject: RE: SL-40
_filtered #yiv1421591727 { font-family:Calibri;} _filtered #yiv1421591727 { font-family:Tahoma;} _filtered #yiv1421591727 { font-family:Bookman Old Style;} _filtered #yiv1421591727 { font-family:Consolas;} _filtered #yiv1421591727 {margin:1.0in 1.0in 1.0in 1.0in;} #yiv1421591727 P.yiv1421591727MsoNormal { MARGIN:0in 0in 0pt;FONT-FAMILY:"serif";FONT-SIZE:12pt;} #yiv1421591727 LI.yiv1421591727MsoNormal { MARGIN:0in 0in 0pt;FONT-FAMILY:"serif";FONT-SIZE:12pt;} #yiv1421591727 DIV.yiv1421591727MsoNormal { MARGIN:0in 0in 0pt;FONT-FAMILY:"serif";FONT-SIZE:12pt;} #yiv1421591727 A:link { COLOR:blue;TEXT-DECORATION:underline;} #yiv1421591727 SPAN.yiv1421591727MsoHyperlink { COLOR:blue;TEXT-DECORATION:underline;} #yiv1421591727 A:visited { COLOR:purple;TEXT-DECORATION:underline;} #yiv1421591727 SPAN.yiv1421591727MsoHyperlinkFollowed { COLOR:purple;TEXT-DECORATION:underline;} #yiv1421591727 PRE { MARGIN:0in 0in 0pt;FONT-FAMILY:"Courier New";FONT-SIZE:10pt;} #yiv1421591727 SPAN.yiv1421591727HTMLPreformattedChar { FONT-FAMILY:"serif";} #yiv1421591727 SPAN.yiv1421591727EmailStyle19 { FONT-FAMILY:"sans-serif";COLOR:#1f497d;} #yiv1421591727 .yiv1421591727MsoChpDefault { FONT-SIZE:10pt;} #yiv1421591727 DIV.yiv1421591727WordSection1 { } If it was me, I would change to the next larger fuse size (7.5amp). Transmitting is not a sustained electrical condition. The fuse is to protect the wire between the fuse and the radio. You may consider metering the actual draw when transmitting for interest sake. You may find that the draw is right close to 5 amps, causing the "nuisance" trips.
If the radio requires a certain amount of electrical power, and the voltage supplied by the ebus is slightly lower due to the diode, then the current draw has to rise slightly to compensate. Perhaps this is causing a slightly higher draw (amps) when operating on the ebus as compared to the main bus..
My opinions only.
Bevan
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On Behalf Of Bill Schlatterer
Sent: Wednesday, June 13, 2012 11:16 AM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: RE: SL-40
Dan just curious, when you say lost … does that mean no power at all or no transmit/receive power? Maybe only on the 430 but it seems like there are two fuses. My SL40 just quit passing any audio to the headphones but still appears to indicate RX/TX as if power is applied and it is working.
Bill S
RV7a
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 12:09 PM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: SL-40
Just when I thought I was out of the woods, an ole nemesis returns. As I mentioned in the last post, my noise going into intercom was canceled by an in-line audio suppressor.
Right after I did a run-up today getting ready to take off, I taxied to the hold-short line and called the tower. I lost my radio. I got back to the hanger to find for the second time I blew the 5 A fuse. The last time this happened was 11 to 12 hours ago. The SL-40 is wired to the E-Bus. I am of course concerned as to why this is happening, but know it could be a tough one to nail down. My thoughts have led me to try running power from the main bus but also using a DPDT switch to be able to flip the power to the radio via the
E-bus should it go south again. Any other ideas are welcome.
Dan B
[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 |
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dan(at)azshowersolutions.
Guest
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| Posted: Wed Jun 13, 2012 4:24 pm Post subject: SL-40 |
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John,
Not off base at all...quite possibly a home run. I just installed an APRS unit and had it running. My antennas should not be an issue as they are quite a ways apart, however I can keep that in mind while at the field and turn it off until I get under way. Nice pitch, thanks!
Dan
From: John Morgensen <john(at)morgensen.com>
To: aeroelectric-list(at)matronics.com
Sent: Wednesday, June 13, 2012 2:42 PM
Subject: Re: SL-40
Probably way off base and a shot in the dark, but I discovered that it is easy to blow the radio fuse if the APRS transmitter broadcasts its periodic packet at the same time I press the transmit button. Separating the antennas solved the problem.
john
On 6/13/2012 10:08 AM, Dan Billingsley wrote: [quote] Just when I thought I was out of the woods, an ole nemesis returns. As I mentioned in the last post, my noise going into intercom was canceled by an in-line audio suppressor.
Right after I did a run-up today getting ready to take off, I taxied to the hold-short line and called the tower. I lost my radio. I got back to the hanger to find for the second time I blew the 5 A fuse. The last time this happened was 11 to 12 hours ago. The SL-40 is wired to the E-Bus. I am of course concerned as to why this is happening, but know it could be a tough one to nail down. My thoughts have led me to try running power from the main bus but also using a DPDT switch to be able to flip the power to the radio via the
E-bus should it go south again. Any other ideas are welcome.
Dan B
[b]
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dan(at)azshowersolutions.
Guest
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| Posted: Wed Jun 13, 2012 4:52 pm Post subject: SL-40 |
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From: Charlie England <ceengland(at)bellsouth.net>
To: aeroelectric-list(at)matronics.com
Sent: Wednesday, June 13, 2012 5:08 PM
Subject: Re: SL-40
One thing that *can* happen is the fuse will get hot if there's a poor connection anywhere in the neighborhood: wire to terminal, terminal to fuse, and back again on the other side of the fuse. Think resistance heater. If it gets hot, it's weaker & vibration will increase the odds of mechanical failure of the fuse link itself. Is it a glass fuse, or one of the newer automotive blade type fuses? (Blade fuses should be somewhat less susceptible to the high resistance issue.) yes, they are the blade (automotive) type. Still something to look for.
Can you monitor voltage at the power terminal of the radio, & watch the voltage when you key the mic & actually transmit? If it drops noticeably, you've got high resistance somewhere in the circuit, & the fuse would be my 1st stop, especially if it's the old glass variety. I do have the ability to watch the voltage on each bus, so I will do that test as well...thanks
Charlie
On 06/13/2012 02:08 PM, Dan Billingsley wrote: [quote] Bevan,
That is good logic in reference to the supplied voltage being a bit lower on the E-bus and kicking up the current. My D-100 is hooked up to the Main bus and my EIS (engine monitor) is on the the E bus. There is consistently about 1.5V lower being showed on the E-bus. I won't rule out the thought of the 7.5A fuse at a later date. I think I will see what happens changing over to the main bus.
Thank you for your input.
Dan
From: B Tomm <fvalarm(at)rapidnet.net> (fvalarm(at)rapidnet.net)
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Sent: Wednesday, June 13, 2012 11:50 AM
Subject: RE: SL-40
#yiv148169709 filtered { font-family:Calibri;} #yiv148169709 filtered { font-family:Tahoma;} #yiv148169709 filtered { font-family:Bookman Old Style;} #yiv148169709 filtered { font-family:Consolas;} #yiv148169709 filtered {margin:1.0in 1.0in 1.0in 1.0in;} #yiv148169709 P.yiv148169709MsoNormal { MARGIN:0in 0in 0pt;FONT-FAMILY:"serif";FONT-SIZE:12pt;} #yiv148169709 LI.yiv148169709MsoNormal { MARGIN:0in 0in 0pt;FONT-FAMILY:"serif";FONT-SIZE:12pt;} #yiv148169709 DIV.yiv148169709MsoNormal { MARGIN:0in 0in 0pt;FONT-FAMILY:"serif";FONT-SIZE:12pt;} #yiv148169709 A:link { COLOR:blue;TEXT-DECORATION:underline;} #yiv148169709 SPAN.yiv148169709MsoHyperlink { COLOR:blue;TEXT-DECORATION:underline;} #yiv148169709 A:visited { COLOR:purple;TEXT-DECORATION:underline;} #yiv148169709 SPAN.yiv148169709MsoHyperlinkFollowed { COLOR:purple;TEXT-DECORATION:underline;} #yiv148169709 PRE { MARGIN:0in 0in 0pt;FONT-FAMILY:"Courier New";FONT-SIZE:10pt;} #yiv148169709 SPAN.yiv148169709HTMLPreformattedChar { FONT-FAMILY:"serif";} #yiv148169709 SPAN.yiv148169709EmailStyle19 { FONT-FAMILY:"sans-serif";COLOR:#1f497d;} #yiv148169709 .yiv148169709MsoChpDefault { FONT-SIZE:10pt;} #yiv148169709 DIV.yiv148169709WordSection1 { } If it was me, I would change to the next larger fuse size (7.5amp). Transmitting is not a sustained electrical condition. The fuse is to protect the wire between the fuse and the radio. You may consider metering the actual draw when transmitting for interest sake. You may find that the draw is right close to 5 amps, causing the "nuisance" trips.
If the radio requires a certain amount of electrical power, and the voltage supplied by the ebus is slightly lower due to the diode, then the current draw has to rise slightly to compensate. Perhaps this is causing a slightly higher draw (amps) when operating on the ebus as compared to the main bus..
My opinions only.
Bevan
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On Behalf Of Bill Schlatterer
Sent: Wednesday, June 13, 2012 11:16 AM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: RE: SL-40
Dan just curious, when you say lost … does that mean no power at all or no transmit/receive power? Maybe only on the 430 but it seems like there are two fuses. My SL40 just quit passing any audio to the headphones but still appears to indicate RX/TX as if power is applied and it is working.
Bill S
RV7a
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 12:09 PM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: SL-40
Just when I thought I was out of the woods, an ole nemesis returns. As I mentioned in the last post, my noise going into intercom was canceled by an in-line audio suppressor.
Right after I did a run-up today getting ready to take off, I taxied to the hold-short line and called the tower. I lost my radio. I got back to the hanger to find for the second time I blew the 5 A fuse. The last time this happened was 11 to 12 hours ago. The SL-40 is wired to the E-Bus. I am of course concerned as to why this is happening, but know it could be a tough one to nail down. My thoughts have led me to try running power from the main bus but also using a DPDT switch to be able to flip the power to the radio via the
E-bus should it go south again. Any other ideas are welcome.
Dan B
"_blank" href="http://www.matronics.com/Navigator?AeroElectric-List">http --> http://www.matronics.com/con================
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Bob McC
Joined: 09 Jan 2006
Posts: 258
Location: Toronto, ON
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| Posted: Wed Jun 13, 2012 5:22 pm Post subject: SL-40 |
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Dan;
You missed Charlie’s point, the voltage at the buss doesn’t tell the story of a high resistance connection at the fuse or in the radio wiring. You must monitor the voltage at the input terminal to the radio as Charlie indicated. This should remain somewhat steady before and during transmit if all is well with the circuit and it should closely approximate the buss voltage.
Bob McC
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 8:52 PM
To: aeroelectric-list(at)matronics.com
Subject: Re: AeroElectric-List: SL-40
From: Charlie England <ceengland(at)bellsouth.net>
To: aeroelectric-list(at)matronics.com
Sent: Wednesday, June 13, 2012 5:08 PM
Subject: Re: AeroElectric-List: SL-40
One thing that *can* happen is the fuse will get hot if there's a poor connection anywhere in the neighborhood: wire to terminal, terminal to fuse, and back again on the other side of the fuse. Think resistance heater. If it gets hot, it's weaker & vibration will increase the odds of mechanical failure of the fuse link itself. Is it a glass fuse, or one of the newer automotive blade type fuses? (Blade fuses should be somewhat less susceptible to the high resistance issue.) yes, they are the blade (automotive) type. Still something to look for.
Can you monitor voltage at the power terminal of the radio, & watch the voltage when you key the mic & actually transmit? If it drops noticeably, you've got high resistance somewhere in the circuit, & the fuse would be my 1st stop, especially if it's the old glass variety. I do have the ability to watch the voltage on each bus, so I will do that test as well...thanks
Charlie
[quote] [b]
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_________________
Bob McC
Falco #908
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ceengland(at)bellsouth.ne
Guest
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| Posted: Wed Jun 13, 2012 5:28 pm Post subject: SL-40 |
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exactly; thanks, Bob
On 06/13/2012 08:20 PM, Bob McCallum wrote: [quote] v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} <![endif]--> st1\:*{behavior:url(#default#ieooui) } <![endif]-->
Dan;
You missed Charlie’s point, the voltage at the buss doesn’t tell the story of a high resistance connection at the fuse or in the radio wiring. You must monitor the voltage at the input terminal to the radio as Charlie indicated. This should remain somewhat steady before and during transmit if all is well with the circuit and it should closely approximate the buss voltage.
Bob McC
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 8:52 PM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: Re: AeroElectric-List: SL-40
From: Charlie England <ceengland(at)bellsouth.net> (ceengland(at)bellsouth.net)
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Sent: Wednesday, June 13, 2012 5:08 PM
Subject: Re: AeroElectric-List: SL-40
One thing that *can* happen is the fuse will get hot if there's a poor connection anywhere in the neighborhood: wire to terminal, terminal to fuse, and back again on the other side of the fuse. Think resistance heater. If it gets hot, it's weaker & vibration will increase the odds of mechanical failure of the fuse link itself. Is it a glass fuse, or one of the newer automotive blade type fuses? (Blade fuses should be somewhat less susceptible to the high resistance issue.) yes, they are the blade (automotive) type. Still something to look for.
Can you monitor voltage at the power terminal of the radio, & watch the voltage when you key the mic & actually transmit? If it drops noticeably, you've got high resistance somewhere in the circuit, & the fuse would be my 1st stop, especially if it's the old glass variety. I do have the ability to watch the voltage on each bus, so I will do that test as well...thanks
Charlie
[b]
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bbradburry(at)bellsouth.n
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| Posted: Wed Jun 13, 2012 5:52 pm Post subject: SL-40 |
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Dan,
I can’t tell from your description if you are talking about the fuse to the radio or the fuse to the e-buss. If it is the fuse to the radio, you must have something wrong with the radio because it only pulls about 2 amps when you transmit, much less to receive.
If you are talking about the fuse to the e-buss, then you are having the same problem that I did with my radio. I had all the stuff that I felt I needed in an emergency going thru the e-buss and following the architecture of Z-19, I had a 7.5 amp fuse on the e-buss.
I had tested everything and it was working fine. This day I was letting the autopilot fly and decided to go back to the airport. I picked up ATIS, then tuned in approach and keyed the mike. About 15 seconds and POP! the entire panel went dark! I sat there stunned! Well, the engine is still running!
You need to size the fuse on the e-buss to handle the total load on the e-buss! If a 2 amp load is blowing a 5 amp fuse, you have the e-buss loaded to about 4+ amps before you hit transmit. Or write the light signals down so you will have them available! :>)
Bill B
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 8:23 PM
To: aeroelectric-list(at)matronics.com
Subject: Re: AeroElectric-List: SL-40
John,
Not off base at all...quite possibly a home run. I just installed an APRS unit and had it running. My antennas should not be an issue as they are quite a ways apart, however I can keep that in mind while at the field and turn it off until I get under way. Nice pitch, thanks!
Dan
From: John Morgensen <john(at)morgensen.com>
To: aeroelectric-list(at)matronics.com
Sent: Wednesday, June 13, 2012 2:42 PM
Subject: Re: AeroElectric-List: SL-40
Probably way off base and a shot in the dark, but I discovered that it is easy to blow the radio fuse if the APRS transmitter broadcasts its periodic packet at the same time I press the transmit button. Separating the antennas solved the problem.
john
On 6/13/2012 10:08 AM, Dan Billingsley wrote:
Just when I thought I was out of the woods, an ole nemesis returns. As I mentioned in the last post, my noise going into intercom was canceled by an in-line audio suppressor.
Right after I did a run-up today getting ready to take off, I taxied to the hold-short line and called the tower. I lost my radio. I got back to the hanger to find for the second time I blew the 5 A fuse. The last time this happened was 11 to 12 hours ago. The SL-40 is wired to the E-Bus. I am of course concerned as to why this is happening, but know it could be a tough one to nail down. My thoughts have led me to try running power from the main bus but also using a DPDT switch to be able to flip the power to the radio via the
E-bus should it go south again. Any other ideas are welcome.
Dan B
[quote] [b]
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email(at)jaredyates.com
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| Posted: Wed Jun 13, 2012 5:58 pm Post subject: SL-40 |
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For what it's worth, in my load analysis, by the GNS-430 VHF com circuit I have written "3.2-6 amps" during the transmit condition, with 4ma-15ma in the receive condition. I'm pretty sure I got that from the Garmin installation manual. I know your radio was made by someone else, but I mention it to help promote the possibility that 5 amps might be a realistic current for a similar VHF radio. The fuse might be doing just what it's been asked to do.
On Wed, Jun 13, 2012 at 9:27 PM, Charlie England <ceengland(at)bellsouth.net (ceengland(at)bellsouth.net)> wrote:
[quote] exactly; thanks, Bob
On 06/13/2012 08:20 PM, Bob McCallum wrote: | Quote: |
Dan;
You missed Charlie’s point, the voltage at the buss doesn’t tell the story of a high resistance connection at the fuse or in the radio wiring. You must monitor the voltage at the input terminal to the radio as Charlie indicated. This should remain somewhat steady before and during transmit if all is well with the circuit and it should closely approximate the buss voltage.
Bob McC
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 8:52 PM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: Re: AeroElectric-List: SL-40
From: Charlie England <ceengland(at)bellsouth.net> (ceengland(at)bellsouth.net)
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Sent: Wednesday, June 13, 2012 5:08 PM
Subject: Re: AeroElectric-List: SL-40
One thing that *can* happen is the fuse will get hot if there's a poor connection anywhere in the neighborhood: wire to terminal, terminal to fuse, and back again on the other side of the fuse. Think resistance heater. If it gets hot, it's weaker & vibration will increase the odds of mechanical failure of the fuse link itself. Is it a glass fuse, or one of the newer automotive blade type fuses? (Blade fuses should be somewhat less susceptible to the high resistance issue.) yes, they are the blade (automotive) type. Still something to look for.
Can you monitor voltage at the power terminal of the radio, & watch the voltage when you key the mic & actually transmit? If it drops noticeably, you've got high resistance somewhere in the circuit, & the fuse would be my 1st stop, especially if it's the old glass variety. I do have the ability to watch the voltage on each bus, so I will do that test as well...thanks
Charlie
ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
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[b]
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dan(at)azshowersolutions.
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| Posted: Wed Jun 13, 2012 6:25 pm Post subject: SL-40 |
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Thanks guys, That gives me info to work with. Will let you know what I find tomorrow.
Dan
From: Jared Yates <email(at)jaredyates.com>
To: aeroelectric-list(at)matronics.com
Sent: Wednesday, June 13, 2012 6:56 PM
Subject: Re: SL-40
For what it's worth, in my load analysis, by the GNS-430 VHF com circuit I have written "3.2-6 amps" during the transmit condition, with 4ma-15ma in the receive condition. I'm pretty sure I got that from the Garmin installation manual. I know your radio was made by someone else, but I mention it to help promote the possibility that 5 amps might be a realistic current for a similar VHF radio. The fuse might be doing just what it's been asked to do.
On Wed, Jun 13, 2012 at 9:27 PM, Charlie England <ceengland(at)bellsouth.net (ceengland(at)bellsouth.net)> wrote:
[quote] exactly; thanks, Bob
On 06/13/2012 08:20 PM, Bob McCallum wrote: | Quote: | Dan;
You missed Charlie’s point, the voltage at the buss doesn’t tell the story of a high resistance connection at the fuse or in the radio wiring. You must monitor the voltage at the input terminal to the radio as Charlie indicated. This should remain somewhat steady before and during transmit if all is well with the circuit and it should closely approximate the buss voltage.
Bob McC
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On Behalf Of Dan Billingsley
Sent: Wednesday, June 13, 2012 8:52 PM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: Re: AeroElectric-List: SL-40
From: Charlie England <ceengland(at)bellsouth.net> (ceengland(at)bellsouth.net)
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Sent: Wednesday, June 13, 2012 5:08 PM
Subject: Re: AeroElectric-List: SL-40
One thing that *can* happen is the fuse will get hot if there's a poor connection anywhere in the neighborhood: wire to terminal, terminal to fuse, and back again on the other side of the fuse. Think resistance heater. If it gets hot, it's weaker & vibration will increase the odds of mechanical failure of the fuse link itself. Is it a glass fuse, or one of the newer automotive blade type fuses? (Blade fuses should be somewhat less susceptible to the high resistance issue.) yes, they are the blade (automotive) type. Still something to look for.
Can you monitor voltage at the power terminal of the radio, & watch the voltage when you key the mic & actually transmit? If it drops noticeably, you've got high resistance somewhere in the circuit, & the fuse would be my 1st stop, especially if it's the old glass variety. I do have the ability to watch the voltage on each bus, so I will do that test as well...thanks
Charlie
ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
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http://www.matronics.com/Navigator?AeroElectric-Listhttp://=======================
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Thu Jun 14, 2012 11:06 am Post subject: SL-40 |
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At 07:08 PM 6/13/2012, you wrote:
The 'low voltage=high current' thing works for AC induction motors,
but I wouldn't bet too heavily on it being the problem in a DC
circuit. If you look at the volts/ohms/amps formulas, you can see why.
Many modern radios have switchmode power supplies that deliver
a constant voltage to the radios internal workings over a wide
range of input voltages. For example, many radios today are
rated to run on 10 to 32 volts DC and will work in any airplane.
It stands to reason then that since the radio expects to see
"constant power availability" over that range of inputs, then
the power supply electronics current draw goes up as input voltage
goes down. A radio with would be expected to draw 3.2 x more current
at 10 volts than it does at 32 volts. Hence, lower bus voltage
translates directly into higher current draw. The radio performs
as advertised over the full range of inputs.
Unless the device is fitted with a constant power energy
system, then the current can generally be expected to go
down as supply voltage goes down . . . with a commensurate
drop in device performance.
One thing that *can* happen is the fuse will get hot if there's a
poor connection anywhere in the neighborhood: wire to terminal,
terminal to fuse, and back again on the other side of the fuse. Think
resistance heater. If it gets hot, it's weaker & vibration will
increase the odds of mechanical failure of the fuse link itself. Is
it a glass fuse, or one of the newer automotive blade type fuses?
(Blade fuses should be somewhat less susceptible to the high resistance issue.)
Can you monitor voltage at the power terminal of the radio, & watch
the voltage when you key the mic & actually transmit? If it drops
noticeably, you've got high resistance somewhere in the circuit, &
the fuse would be my 1st stop, especially if it's the old glass variety.
It is a widely circulated myth that some devices
should be expected to draw more current at lower supply
voltages . . . especially motors. Output torque is
proportional to current in the armature. If the motor
is powering something that demands more torque as
the speed drops, then yes, current will go up. This is
NOT because of any special characteristic of the motor;
rather a characteristic of the system the motor drives.
Also, increased resistance in the loop of any closed
system will drop the voltage available elsewhere in the
loop while increasing energy dissipated in the localized
loss of conduction. But thermally operated fuses and
breakers are oblivious to such events. They only know
how many electrons per second they're asked to carry
(amps) and will perform accordingly.
Bob . . .
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dan(at)azshowersolutions.
Guest
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| Posted: Thu Jun 14, 2012 12:04 pm Post subject: SL-40 |
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From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>
To: aeroelectric-list(at)matronics.com
Sent: Thursday, June 14, 2012 12:03 PM
Subject: Re: SL-40
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>
At 07:08 PM 6/13/2012, you wrote:
The 'low voltage=high current' thing works for AC induction motors, but I wouldn't bet too heavily on it being the problem in a DC circuit. If you look at the volts/ohms/amps formulas, you can see why.
Many modern radios have switchmode power supplies that deliver
a constant voltage to the radios internal workings over a wide
range of input voltages. For example, many radios today are
rated to run on 10 to 32 volts DC and will work in any airplane.
It stands to reason then that since the radio expects to see
"constant power availability" over that range of inputs, then
the power supply electronics current draw goes up as input voltage
goes down. A radio with would be expected to draw 3.2 x more current
at 10 volts than it does at 32 volts. Hence, lower bus voltage
translates directly into higher current draw. The radio performs
as advertised over the full range of inputs.So with the E-Bus operating at somewhere around 1.5V lower than the main bus, then there may be a possibility of radio transmission kicking the current high enough to burn the fuse? Or do you think there may be more going on here (like some unwanted resistance)? I wasn't able to get to the field today (so no testing yet) but there were a couple suggestions / thoughts...
(a) change out the 5A fuse to 7.5A and call it good (still on the E-bus).
(b) move the SL-40 power to the main bus with a switch to send it over to the E-bus should it go south again.
and another thought...do I remember correctly (Z-16) that changing over to your schottkey diode may increase the available voltage on the E-bus?
So the question....WWBD (what would bob do?)
Also, increased resistance in the loop of any closed
system will drop the voltage available elsewhere in the
loop while increasing energy dissipated in the localized
loss of conduction. But thermally operated fuses and
breakers are oblivious to such events. They only know
how many electrons per second they're asked to carry
(amps) and --> http://www.matronics.com/Navigator?AeroElectric-List
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Thu Jun 14, 2012 12:15 pm Post subject: SL-40 |
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At 09:22 PM 6/13/2012, you wrote:
| Quote: | Thanks guys, That gives me info to work with. Will let you know what I find tomorrow.
Dan
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Dan, have you ever published a diagram of your architecture?
It's not clear to me where the 'problem fuse' is located
in your system.
[quote] Bob . . .[/b] [quote][b]
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Thu Jun 14, 2012 1:19 pm Post subject: SL-40 |
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So with the E-Bus operating at somewhere around 1.5V lower than the main bus, then there may be a possibility of radio transmission kicking the current high enough to burn the fuse?
If the fuse is already being pushed to the edge . . . yes.
What engine are we talking about . . . and alternator?
If a Rotax, then the alternator is essentially non-op
on the ground so you've got battery voltage less diode
drop (1.5 is too much . . . it should be more like .7
for silicon junction and .5 for Schottky device). So
on the ground your system supply is basically a battery
(12.5 volts) + diode drop might take you down to 12.0
volts or less. This would cause the radio to draw 14/12
or 16% more current than in cruising flight . . . still
more if the battery is soggy. You should not have any
fuse loaded to more than 75% of rated value anywhere in
the system under any operating condition.
Or do you think there may be more going on here (like some unwanted resistance)? I wasn't able to get to the field today (so no testing yet) but there were a couple suggestions / thoughts...
If you have 'unwanted resistance' it's in the normal
feed path wiring that might add to total drop in that
path . . . but that shouldn't add more than 0.1 volt or
so on top of diode drop.
(a) change out the 5A fuse to 7.5A and call it good (still on the E-bus).
Do some measurements. KNOW why the fuse is popping . . .
(b) move the SL-40 power to the main bus with a switch to send it over to the E-bus should it go south again.
and another thought...do I remember correctly (Z-16) that changing over to your schottkey diode may increase the available voltage on the E-bus?
By a few tenths of a volt, yes. But if you're slicing your
energy pie up in slices that thin, there's no robustness
in your design. Check every fuse and make sure it's rated
for at least 1.5x max service draw. Recall that fuses protect
wires from HARD faults, no wire ever burned from a soft fault
(2-4x overload).
The 22AWG wire in this photo has been loaded to 20Amps for
over 10 minutes
http://tinyurl.com/6qr72fr
. . . so don't get wrapped around the 'ratings' axle
for fuses versus wire size. Nuisance trips are to be
designed out before you go flying.
So the question....WWBD (what would bob do?)
Get some measurements. Resize fuses as needed.
From the SL40 Installation Manual:
[img]cid:.0[/img]
The 3.2A max at 13.75 could be 3.6A at 12 volts. The radio
has a 7A fast blow fuse installed inside. So where is
the 7.5A fuse? If it's on your battery bus to protect the
alternate feed path, then this fuse would could be loaded
to 3.6 amps PLUS what ever else is on the E-bus . . .
need to know what all the numbers are.
Bob . . .
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dan(at)azshowersolutions.
Guest
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| Posted: Thu Jun 14, 2012 1:19 pm Post subject: SL-40 |
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From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>
To: aeroelectric-list(at)matronics.com
Sent: Thursday, June 14, 2012 1:14 PM
Subject: Re: SL-40
At 09:22 PM 6/13/2012, you wrote:
| Quote: | Thanks guys, That gives me info to work with. Will let you know what I find tomorrow.
Dan
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Dan, have you ever published a diagram of your architecture?
It's not clear to me where the 'problem fuse' is located
in your system.
Bob, the problem fuse is on the E-bus (Z-16) going to the SL-40 radio. I have a 5A fuse there as called out in the installation manual. I used the bridge rectifier from Radio Shack between the main and the E. I can sketch out what loads are sitting where between the two busses if that would help. When I installed everything I was wanting on the E-bus, I ended up getting a total load of about 7A (measuring across the E switch with it off). That was checked and included keying the radio. I know your book says the E bus should carry a Max of 4 A continuous load, but when I mentioned it here, I was told it should be a non-issue as the transmitting only occurs in short bursts. So perhaps I SHOULD be using your diode instead of the rectifier? I need to do these and more Voltage & Amp tests to know where I sit now as I have not tested since the install.
Dan
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nuckolls.bob(at)aeroelect
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| Posted: Fri Jun 15, 2012 9:49 am Post subject: SL-40 |
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| Quote: | | Bob, the problem fuse is on the E-bus (Z-16) going to the SL-40 radio. I have a 5A fuse there as called out in the installation manual. |
Yeah, I recall now.
Okay, if you're blowing that fuse, it's because the
radio draws enough current to do it. Do I recall that
the fuse does not pop if the alternate feed switch to
the e-bus is closed? A useful experiment would be to
leave the alternate feed switch on for all normal ops.
Turn it on before master switch, off after master
switch. See if the fuse blowing behavior changes.
[quote] Bob . . . [quote][b]
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