AeroElectric-List Digest Archive

Sun 10/28/12


Total Messages Posted: 4



Today's Message Index:
----------------------
 
     1. 06:24 AM - Re: turn coordinator causing noise in headset (Eric M. Jones)
     2. 12:24 PM - Re: Hand-Held NAV-COM (Robert L. Nuckolls, III)
     3. 05:36 PM - B&C alternator diagnosis (Henry Hallam)
     4. 06:05 PM - Re: B&C alternator diagnosis (Henry Hallam)
 
 
 


Message 1


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    Time: 06:24:57 AM PST US
    Subject: Re: turn coordinator causing noise in headset
    From: "Eric M. Jones" <emjones@charter.net>
    Might I suggest that the T/C noise might be an indication that the T/C needs repair/mods/replacement? (I have no notion of what is inside it. But I'd sure start looking there.) -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=386140#386140


    Message 2


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    Time: 12:24:13 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Hand-Held NAV-COM
    At 12:03 PM 10/27/2012, you wrote: >I have an old hand-held NAV-COM marketed by Satellite Technology >Services, Inc. of St. Louis, MO. It works well on 720 channels of >COM and 200 channels of NAV, but the center pin of the external >power-supply jack is broken. It has a removable battery pack that >takes 6 AA batteries. The instruction manual talks about a 7.2-volt >NiCad battery pack, but it works well using 6 alkaline batteries (9 >volts). However, it uses up the batteries quite rapidly, and I >would like to find a way of attaching an external power supply. > >I checked the web and found 3 references to the company, a BBB >report, a lawsuit, and a patent assignment. Apparently they don't >have a web site. I don't know whether they still support the radio. > >My options seem to be: >1. Replace the power-supply jack. It seems to be a special jack >that is soldered into the main board. I have not been able to find >the correct jack from any of the usual electronics suppliers. > >2. Remove the jack, solder a pigtail to the board, and connect the >pigtail to a new jack that would dangle from the case. > >3. Modify the battery pack, possibly by making a pair of dummy >batteries that would connect to an external power jack. This is >attractive because the instruction manual says to disconnect the >battery pack (to avoid damaging it) when the external power supply is used. > >Whichever option I choose I will need two power supplies, one to >connect to connect to the cigarette-lighter in the airplane, and the >other to connect to the 120-V AC power. Any suggestions for these? Search on STS "AV-7600" and you'll get more hits. A friend of mine in Wichita works on hand-helds and might be able to repair/replace the existing jack. If you go the pigtail route, you can power up from a/c mains with a power supply like this: http://tinyurl.com/963xg74 there are many similar models at very reasonable prices on eBay. You probably don't want to apply a 14-15 volt bus directly to this radio. Some sort of boost-buck dc/dc converter that will give you a constant 12v out for a range of inputs that goes both above and below the output setting. http://tinyurl.com/9dqt39k Bob . . . >----- >Lynn Cole ><mailto:LynnCole@foxvalley.net>LynnCole@foxvalley.net > > ><http://www.matronics.com/Navigator?AeroElectric-List>http://www.matronics.com/Navigator?AeroElectric-List ><http://www.matronics.com/contribution>http://www.matronics.com/contribution > > >No virus found in this message. >Checked by AVG - <http://www.avg.com>www.avg.com Bob . . .


    Message 3


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    Time: 05:36:22 PM PST US
    From: Henry Hallam <henry@pericynthion.org>
    Subject: B&C alternator diagnosis
    Dear Bob et al, I'm the owner but not the builder of a 1979 VariEze equipped with a starterless O-200 and a B&C alternator (the 12-amp 200G model, I believe). I don't have an ammeter in the cockpit. I do have an LED bar-graph voltmeter in which I have placed little trust over the past year or so, since it was showing around 12 volts rather than the expected 13+. Perhaps I should have been more trusting. Last week I had an electrical failure in flight, on a nice day over familiar terrain. The first sign of trouble was the backlight brightness decreasing on my Garmin 480; it subsequently reset itself and then failed entirely. I have one magneto and one Lightspeed electronic ignition, and not much else in the way of electronics in the cockpit. Turning off the magneto resulted in rough running - presumably the EI was trying its best to keep up with the low bus voltage but didn't have enough juice to fire every time. Anyway I got the green light signal from Livermore tower and landed without incident. The battery measured 11.7 volts open-circuit. This weekend I tried to diagnose the problem. The alternator circuit breaker seems to be fine. I removed the regulator (see pics linked below). The B&C alternator is a brushless model and only has two wires coming out of it; I think the regulator is essentially a bridge rectifier and a linear voltage regulator. B&C currently seems to sell a separate "rectifier-type regulator" [1] and "crowbar" overvoltage protection circuit [2]. I'm not sure if what I have is just the regulator or a combination of the two. It looks to be completely potted in resin except for one adjustment screw. It has four wires - red (bus +), black (gnd) and two blue (alternator). With a multimeter on diode mode I measured 0.55V drop from either blue wire to the red, as you'd expect with a bridge rectifier. There was also 1.2V drop from black to red, again as would be expected. But it showed "open circuit" from black to either blue. Adjusting the screw (which appeared to turn freely for 20+ revolutions, like one of those multi-turn pots with the clutch) made no difference. I plugged the regulator back in to the alternator (but not to the aircraft bus), started the engine and observed 0.0V output on the red and black wires. I disconnected the regulator again, measured the alternator wires directly and saw around 17V AC. So - the regulator's bad, right? It's not just trying to do something clever in response to an open bus connection? I just want to be sure I'm not missing something before I order a new one. Thanks very much, Henry Photos: Alternator - http://i.imgur.com/nIWgG.jpg http://i.imgur.com/w8WlE.jpg http://i.imgur.com/ihwXI.jpg Regulator - http://i.imgur.com/QXQUr.jpg http://i.imgur.com/ng9TH.jpg [1] http://www.bandc.biz/regulator14vhomebuilt.aspx [2] http://www.bandc.biz/pmovfilterandovprotectionkit14v.aspx


    Message 4


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    Time: 06:05:07 PM PST US
    From: Henry Hallam <henry@pericynthion.org>
    Subject: Re: B&C alternator diagnosis
    The mystery deepens. I connected the regulator to the alternator and hooked the output of the regulator directly to the battery. Ran the engine, saw the battery voltage increase from 12.15V (to which I had previously trickle-charged it) to 12.4V and gradually over a few minutes up to 12.8V. I removed the regulator output from the battery (engine still running) and saw the output voltage from the regulator rise to 15.0V. Connected it back to the battery via an ammeter and saw 3.5A charge current - roughly what I should expect for an engine idling around 1100 rpm. Adjusting the regulator's screw while all this was happening didn't seem to change much. So now I'm at a loss - it seems to be working again. Do you think it's still a good idea to replace the regulator? The only other thing I noticed is that one screw terminal on the battery was not tight - not terribly loose, but I could undo it with just my fingers. I guess I will put it all back together with a trusted voltmeter in the cockpit and go fly in VMC for a while, but I'd love to hear ideas. Thanks, Henry On Sun, Oct 28, 2012 at 5:34 PM, Henry Hallam <henry@pericynthion.org> wrote: > > Dear Bob et al, > > I'm the owner but not the builder of a 1979 VariEze equipped with a > starterless O-200 and a B&C alternator (the 12-amp 200G model, I > believe). I don't have an ammeter in the cockpit. I do have an LED > bar-graph voltmeter in which I have placed little trust over the past > year or so, since it was showing around 12 volts rather than the > expected 13+. Perhaps I should have been more trusting. > > Last week I had an electrical failure in flight, on a nice day over > familiar terrain. The first sign of trouble was the backlight > brightness decreasing on my Garmin 480; it subsequently reset itself > and then failed entirely. I have one magneto and one Lightspeed > electronic ignition, and not much else in the way of electronics in > the cockpit. Turning off the magneto resulted in rough running - > presumably the EI was trying its best to keep up with the low bus > voltage but didn't have enough juice to fire every time. Anyway I got > the green light signal from Livermore tower and landed without > incident. The battery measured 11.7 volts open-circuit. > > This weekend I tried to diagnose the problem. The alternator circuit > breaker seems to be fine. I removed the regulator (see pics linked > below). The B&C alternator is a brushless model and only has two > wires coming out of it; I think the regulator is essentially a bridge > rectifier and a linear voltage regulator. B&C currently seems to sell > a separate "rectifier-type regulator" [1] and "crowbar" overvoltage > protection circuit [2]. I'm not sure if what I have is just the > regulator or a combination of the two. It looks to be completely > potted in resin except for one adjustment screw. It has four wires - > red (bus +), black (gnd) and two blue (alternator). > > With a multimeter on diode mode I measured 0.55V drop from either blue > wire to the red, as you'd expect with a bridge rectifier. There was > also 1.2V drop from black to red, again as would be expected. But it > showed "open circuit" from black to either blue. Adjusting the screw > (which appeared to turn freely for 20+ revolutions, like one of those > multi-turn pots with the clutch) made no difference. > > I plugged the regulator back in to the alternator (but not to the > aircraft bus), started the engine and observed 0.0V output on the red > and black wires. I disconnected the regulator again, measured the > alternator wires directly and saw around 17V AC. > > So - the regulator's bad, right? It's not just trying to do something > clever in response to an open bus connection? I just want to be sure > I'm not missing something before I order a new one. > > > Thanks very much, > Henry > > Photos: > Alternator - http://i.imgur.com/nIWgG.jpg > http://i.imgur.com/w8WlE.jpg http://i.imgur.com/ihwXI.jpg > Regulator - http://i.imgur.com/QXQUr.jpg http://i.imgur.com/ng9TH.jpg > > > [1] http://www.bandc.biz/regulator14vhomebuilt.aspx > [2] http://www.bandc.biz/pmovfilterandovprotectionkit14v.aspx > >




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