---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 12/06/15: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:35 AM - Re: strobe capacitors (Robert L. Nuckolls, III) 2. 10:19 AM - Re: Troubleshooting radio whine/noise on C essna 182P (sacha) 3. 10:22 AM - Re: strobe capacitors (Bill Bradburry) 4. 10:44 AM - Re: strobe capacitors (Sheldon Olesen) 5. 01:50 PM - Re: Re: Troubleshooting radio whine/noise on C essna 182P (Charlie England) 6. 02:34 PM - Re: Troubleshooting radio whine/noise on C essna 182P (sacha) 7. 03:10 PM - Re: Re: Troubleshooting radio whine/noise on C essna 182P (jan) 8. 04:15 PM - Re: strobe capacitors (Jeff Luckey) 9. 04:16 PM - Weak Starter (John Morgensen) 10. 04:53 PM - Re: Weak Starter (Justin Jones) 11. 05:50 PM - Re: Weak Starter (Charlie England) 12. 05:56 PM - Re: Weak Starter (Charlie England) 13. 06:42 PM - Re: Weak Starter (Kelly McMullen) ________________________________ Message 1 _____________________________________ Time: 09:35:49 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: strobe capacitors At 02:49 PM 12/4/2015, you wrote: >Sheldon, > >It would be good to confirm that the caps are the problem before you >start swapping parts. Sudden failures in strobes are seldom, if ever, rooted in failures of the energy storage capacitors. Those devices decay with age and use resulting in a decrease of light output for each firing . . . but they don't suddenly turn turttle. A sudden failure is more likely a failure of the trigger circuitry -OR- loss of the dc/dc converter that develops high voltage to charge the capacitors. Bob . . . ________________________________ Message 2 _____________________________________ Time: 10:19:01 AM PST US Subject: AeroElectric-List: Re: Troubleshooting radio whine/noise on C essna 182P From: "sacha" Thanks for your explanation about the radio grounding. It's obvious when one thinks about it. I'm still struggling with this. I rechecked the capacitors and they measure 5.7 uF for the S1915 which is correct and 3.54 uF for the RFI filter (Cessna part 0770038-2) which seems like a plausible value. So the only remaining possibility seems to be some bad connection somewhere, most likely on the ground side of things. But the puzzle remains as to why an alternator that fails can suddenly cause a grounding problem. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=450764#450764 ________________________________ Message 3 _____________________________________ Time: 10:22:44 AM PST US From: "Bill Bradburry" Subject: RE: AeroElectric-List: strobe capacitors I had a problem with my strobes where they would fire 2-3 times and then stop. My VOM showed 12 volts at the connector going into the strobe. I finally replaced both the power and ground wires and connectors and the problem went away, apparently a high resistance connection on one or both ends of one of the power/ground wires. Have you checked for that? Bill _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Sunday, December 06, 2015 11:34 AM Subject: Re: AeroElectric-List: strobe capacitors At 02:49 PM 12/4/2015, you wrote: Sheldon, It would be good to confirm that the caps are the problem before you start swapping parts. Sudden failures in strobes are seldom, if ever, rooted in failures of the energy storage capacitors. Those devices decay with age and use resulting in a decrease of light output for each firing . . . but they don't suddenly turn turttle. A sudden failure is more likely a failure of the trigger circuitry -OR- loss of the dc/dc converter that develops high voltage to charge the capacitors. Bob . . . ________________________________ Message 4 _____________________________________ Time: 10:44:59 AM PST US From: Sheldon Olesen Subject: Re: AeroElectric-List: strobe capacitors I was hoping that the capacitors were the culprit because that was something I could possibly deal with. I tested the capacitors as suggested by Joe G ores and found they would spark if shorted, so from that I concluded that th ey were ok and the problem wasn't fixable by me. With a defunct manufactur er, replacement seems to be my only option. Thanks to all who replied. Sheldon Olesen Sent from my iPad > On Dec 6, 2015, at 12:33 PM, Robert L. Nuckolls, III wrote: > > At 02:49 PM 12/4/2015, you wrote: >> Sheldon, >> >> It would be good to confirm that the caps are the problem before you star t swapping parts. > > Sudden failures in strobes are seldom, if ever, rooted > in failures of the energy storage capacitors. Those devices > decay with age and use resulting in a decrease of light > output for each firing . . . but they don't suddenly > turn turttle. > > A sudden failure is more likely a failure of the > trigger circuitry -OR- loss of the dc/dc converter > that develops high voltage to charge the capacitors. > > > Bob . . . ________________________________ Message 5 _____________________________________ Time: 01:50:14 PM PST US Subject: Re: AeroElectric-List: Re: Troubleshooting radio whine/noise on C essna 182P From: Charlie England On Sun, Dec 6, 2015 at 12:17 PM, sacha wrote: > > Thanks for your explanation about the radio grounding. It's obvious when > one thinks about it. > > I'm still struggling with this. I rechecked the capacitors and they > measure 5.7 uF for the S1915 which is correct and 3.54 uF for the RFI > filter (Cessna part 0770038-2) which seems like a plausible value. > > So the only remaining possibility seems to be some bad connection > somewhere, most likely on the ground side of things. But the puzzle > remains as to why an alternator that fails can suddenly cause a grounding > problem. > > Perhaps it wasn't the failure, but the repair/replacement process. ________________________________ Message 6 _____________________________________ Time: 02:34:42 PM PST US Subject: AeroElectric-List: Re: Troubleshooting radio whine/noise on C essna 182P From: "sacha" (Thanks to Neal/Bob/Paul/Charles/Joe/Jan and everyone else for patiently continuing to help me troubleshoot this issue). Charles>Perhaps it wasn't the failure, but the repair/replacement process. It couldn't have been the repair process because as soon as I landed I pushed the ALT CB back in and the whine appeared. I naturally assumed it was caused by a broken alternator but swapping it out didn't make the whine disappear. (On Friday I took some measurements on the old alternator and confirmed that it does have damage to it's stator coil - this was kindly confirmed to me by my local NAPA store***). Anyway, today I had the following thought process which makes me think that maybe the audio panel got damaged in some way: The alternator noise is audible even with the radios off. Therefore the noise must be entering one of the two wires to the headphone, either the positive or the ground. Thinking about the audio ground, I recall that the black wires are all locally grounded at a post below the instrument panel. So the test I did yesterday (unscrew the jacks from the locally grounded aluminium brackets and see if the noise disappears) was actually useless as a test. What needs to happen (as Joe and Jan have pointed out) is that the ground leads for each headphone needs to be run all the way back to the audio panel instead of being attached locally to the airframe. But I still can't see how loosing an Alternator could magically bring about this condition since nothing changed with the audio jacks. Unless of course the audio panel was damaged by this event. Fixing the audio grounds is cheap, so I guess I'm going to try that first, but I have a bad feeling that the audio panel might be damaged. I know little about audio panels - do they have failure modes in which they "transmit" alternator whine? Sacha *** I got lucky - the NAPA store did this for free. There was a guy there that managed to look up the equivalent automotive model... it took him a while since what was marked on the alternator (D0FF10300J) did not yield any immediate results. However he was persistent and eventually he found out that a 65A Alternator for a 1969 Ford pickup truck was practically identical. Once he had this information, he put the alternator into an automated bench tester which spit out the "stator failed" information a minute later. For those of you who are interested, I'm attaching the a nice PDF which documents the troubleshooting and overhaul procedure for Ford (now Motorcraft) alternators which I got here: http://vintage.mitchell1.com/PClubData/chassis/elt82/V2D824014.pdf Read this topic online here: http://forums.matronics.com/viewtopic.php?p=450771#450771 Attachments: http://forums.matronics.com//files/motorcraft_alternators_troubleshooting_and_overhaul__v2d824014_188.pdf ________________________________ Message 7 _____________________________________ Time: 03:10:08 PM PST US From: jan Subject: RE: AeroElectric-List: Re: Troubleshooting radio whine/noise on C essna 182P How hard would it be for you to bypass the audio panel ? Could you make a jumper up so that you hard wired the headphones & mic directly to your radio for testing purpose ? -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of sacha Sent: 06 December 2015 22:33 Subject: AeroElectric-List: Re: Troubleshooting radio whine/noise on C essna 182P (Thanks to Neal/Bob/Paul/Charles/Joe/Jan and everyone else for patiently continuing to help me troubleshoot this issue). Charles>Perhaps it wasn't the failure, but the repair/replacement process. It couldn't have been the repair process because as soon as I landed I pushed the ALT CB back in and the whine appeared. I naturally assumed it was caused by a broken alternator but swapping it out didn't make the whine disappear. (On Friday I took some measurements on the old alternator and confirmed that it does have damage to it's stator coil - this was kindly confirmed to me by my local NAPA store***). Anyway, today I had the following thought process which makes me think that maybe the audio panel got damaged in some way: The alternator noise is audible even with the radios off. Therefore the noise must be entering one of the two wires to the headphone, either the positive or the ground. Thinking about the audio ground, I recall that the black wires are all locally grounded at a post below the instrument panel. So the test I did yesterday (unscrew the jacks from the locally grounded aluminium brackets and see if the noise disappears) was actually useless as a test. What needs to happen (as Joe and Jan have pointed out) is that the ground leads for each headphone needs to be run all the way back to the audio panel instead of being attached locally to the airframe. But I still can't see how loosing an Alternator could magically bring about this condition since nothing changed with the audio jacks. Unless of course the audio panel was damaged by this event. Fixing the audio grounds is cheap, so I guess I'm going to try that first, but I have a bad feeling that the audio panel might be damaged. I know little about audio panels - do they have failure modes in which they "transmit" alternator whine? Sacha *** I got lucky - the NAPA store did this for free. There was a guy there that managed to look up the equivalent automotive model... it took him a while since what was marked on the alternator (D0FF10300J) did not yield any immediate results. However he was persistent and eventually he found out that a 65A Alternator for a 1969 Ford pickup truck was practically identical. Once he had this information, he put the alternator into an automated bench tester which spit out the "stator failed" information a minute later. For those of you who are interested, I'm attaching the a nice PDF which documents the troubleshooting and overhaul procedure for Ford (now Motorcraft) alternators which I got here: http://vintage.mitchell1.com/PClubData/chassis/elt82/V2D824014.pdf Read this topic online here: http://forums.matronics.com/viewtopic.php?p=450771#450771 Attachments: http://forums.matronics.com//files/motorcraft_alternators_troubleshooting_an d_overhaul__v2d824014_188.pdf ________________________________ Message 8 _____________________________________ Time: 04:15:41 PM PST US From: Jeff Luckey Subject: Re: AeroElectric-List: strobe capacitors I find failed capacitors in all kinds of devices are the culprit on a regul ar basis. And specifically remember finding a bad caps in a strobe system o n a friends airplane several years ago. In addition, it is still generally good trouble-shooting practice to confir m the failure of a component, as opposed to a random remove & replace drill .. -Jeff On Sunday, December 6, 2015 9:45 AM, "Robert L. Nuckolls, III" wrote: At 02:49 PM 12/4/2015, you wrote: Sheldon, It would be good to confirm that the caps are the problem before youstart s wapping parts. =C2-Sudden failures in strobes are seldom, if ever, rooted =C2-in failures of the energy storage capacitors. Those devices =C2-decay with age and use resulting in a decrease of light =C2-output for each firing . . . but they don't suddenly =C2-turn turttle. =C2-A sudden failure is more likely a failure of the =C2-trigger circuitry -OR- loss of the dc/dc converter =C2-that develops high voltage to charge the capacitors. =C2- Bob . . . ________________________________ Message 9 _____________________________________ Time: 04:16:38 PM PST US From: John Morgensen Subject: AeroElectric-List: Weak Starter My Skytec starter barely turns over an IO320. I measured: Battery 13.12 volts. "On" side of master contactor to airframe ground 12.25 volts. "On" side of starter contactor to airframe ground while cranking 8.6 to 9.0 volts. Big wire on starter to airframe ground while cranking is 8.6 volts or less. All this was done with a genuine Harbor Freight $4.00 digital meter. I believe that this points to the starter contactor as the culprit. Correct? john ________________________________ Message 10 ____________________________________ Time: 04:53:11 PM PST US From: Justin Jones Subject: Re: AeroElectric-List: Weak Starter Is say high resistance in the starter contactor More than likely due to internal arcing. This causes corrosion and pitting. Slap a new contactor on there and I bet it fixes the issue. Afterwards, dissect the old contactor to see exactly what happens internally. Justin. > On Dec 6, 2015, at 16:15, John Morgensen wrote: > > > My Skytec starter barely turns over an IO320. > > I measured: > > Battery 13.12 volts. > "On" side of master contactor to airframe ground 12.25 volts. > "On" side of starter contactor to airframe ground while cranking 8.6 to 9.0 volts. > Big wire on starter to airframe ground while cranking is 8.6 volts or less. > > All this was done with a genuine Harbor Freight $4.00 digital meter. I believe that this points to the starter contactor as the culprit. Correct? > > john > > > > > > ________________________________ Message 11 ____________________________________ Time: 05:50:45 PM PST US Subject: Re: AeroElectric-List: Weak Starter From: Charlie England On 12/6/2015 6:15 PM, John Morgensen wrote: > > > My Skytec starter barely turns over an IO320. > > I measured: > > Battery 13.12 volts. > "On" side of master contactor to airframe ground 12.25 volts. > "On" side of starter contactor to airframe ground while cranking 8.6 > to 9.0 volts. > Big wire on starter to airframe ground while cranking is 8.6 volts or > less. > > All this was done with a genuine Harbor Freight $4.00 digital meter. I > believe that this points to the starter contactor as the culprit. > Correct? > > john 12.25 volts with minimal load (contactor coil only) *might* be a little weak for a fully charged battery. The measurement doesn't really mean a lot if there's no load on the other side of the contactor. You could put a 100,000 ohm resistor in series & still measure full battery voltage on the other side of the resistor, as long as there's no load to ground. What's the measurement at the 'on' side of the master contactor while cranking? (Don't change test conditions.) Another method of measurement when looking for bad joints/high resistance in a high current circuit: 1. Measure from the battery positive post (not the bolt or clamp) to the starter positive post while cranking. A voltage drop of greater than ~1/2 volt means you have a high resistance somewhere between battery & starter. 2. Measure from the frame (ground) of the starter to the actual negative post on the battery (not the bolt or clamp) while cranking. That measurement should again be less than 1/2 volt. If not, you have high resistance in the ground circuit. 8.5-9 volts across the starter windings while under load really doesn't sound bad, as long as the rest of the circuit is 'right' and the battery is in good shape. Charlie ________________________________ Message 12 ____________________________________ Time: 05:56:24 PM PST US Subject: Re: AeroElectric-List: Weak Starter From: Charlie England On 12/6/2015 7:50 PM, Charlie England wrote: > On 12/6/2015 6:15 PM, John Morgensen wrote: >> >> >> My Skytec starter barely turns over an IO320. >> >> I measured: >> >> Battery 13.12 volts. >> "On" side of master contactor to airframe ground 12.25 volts. >> "On" side of starter contactor to airframe ground while cranking 8.6 >> to 9.0 volts. >> Big wire on starter to airframe ground while cranking is 8.6 volts or >> less. >> >> All this was done with a genuine Harbor Freight $4.00 digital meter. >> I believe that this points to the starter contactor as the culprit. >> Correct? >> >> john Edit: I missed the 1st line, battery 13.2 & load side of contactor at 12.25. The contacts in the master contactor have really high resistance to see that much drop. > 12.25 volts with minimal load (contactor coil only) *might* be a > little weak for a fully charged battery. The measurement doesn't > really mean a lot if there's no load on the other side of the > contactor. You could put a 100,000 ohm resistor in series & still > measure full battery voltage on the other side of the resistor, as > long as there's no load to ground. What's the measurement at the 'on' > side of the master contactor while cranking? (Don't change test > conditions.) > > Another method of measurement when looking for bad joints/high > resistance in a high current circuit: > > 1. Measure from the battery positive post (not the bolt or clamp) to > the starter positive post while cranking. A voltage drop of greater > than ~1/2 volt means you have a high resistance somewhere between > battery & starter. > > 2. Measure from the frame (ground) of the starter to the actual > negative post on the battery (not the bolt or clamp) while cranking. > That measurement should again be less than 1/2 volt. If not, you have > high resistance in the ground circuit. > > 8.5-9 volts across the starter windings while under load really > doesn't sound bad, as long as the rest of the circuit is 'right' and > the battery is in good shape. > > Charlie ________________________________ Message 13 ____________________________________ Time: 06:42:59 PM PST US Subject: Re: AeroElectric-List: Weak Starter From: Kelly McMullen You probably need to replace both starter relay and master relay. Download Skytec's troubleshooting chart and follow it carefully. On 12/6/2015 5:15 PM, John Morgensen wrote: > > > My Skytec starter barely turns over an IO320. > > I measured: > > Battery 13.12 volts. > "On" side of master contactor to airframe ground 12.25 volts. > "On" side of starter contactor to airframe ground while cranking 8.6 > to 9.0 volts. > Big wire on starter to airframe ground while cranking is 8.6 volts or > less. > > All this was done with a genuine Harbor Freight $4.00 digital meter. I > believe that this points to the starter contactor as the culprit. > Correct? > > john > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.