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  #1  
Old 07-17-2010, 12:03 PM
applewrangle applewrangle is offline
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AR-13A Heathkit Schematic

Howdy,

Does anybody have a Heathkit AR-13A schematic they could email me? I have one of those suckers with a blown output.

At least two of the output PNPs are gone and one of the bridge diodes. Maybe some other stuff. One of the large electrolitic caps smokes when I turn it on. When I tested it with an ohmeter it tested good. I think I also put 12V across it with no current, so think it is just getting too much voltage, for some reason.

Present thinking is to convert to silicon output as the germaniums seem to be pretty hard to come by.

I did find a schematic, on some site, for thirty bucks but was hoping to find somebody that had one and was willing to send it to me.

Thanks in advance,

DZ
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  #2  
Old 07-18-2010, 12:26 PM
ecluser ecluser is offline
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It is very easy to convert to silicon transistors.
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  #3  
Old 07-19-2010, 01:29 AM
applewrangle applewrangle is offline
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AR-13A Heathkit Schematic

If I had a schematic.

DZ
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  #4  
Old 07-19-2010, 09:00 AM
ecluser ecluser is offline
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I sent you a PM for the schematic.

The original power transistors are 2N2147 and the bias is provided by germanium diodes 1N2326. Replace the transistors by silicon ones, like the easy to find 2N2955, and the diodes by silicon ones (1N4002 for example)
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  #5  
Old 10-17-2010, 08:42 PM
dotyb dotyb is offline
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Hi,

I'm also looking for a schematic for the AR-13A and have been very unsuccessful.

I am tracing back what seems to be a 60Hz hum that is evident on all bands. The loudness of the hum is loudest on FM, next on AM and least on the Aux 1 and 2. I'm looking to recap the unit but am unsure of the values for the large metal capacitors. This is my first restore attempt for any radio.

Thanks for any help!
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  #6  
Old 06-21-2013, 02:45 PM
bobsnewname bobsnewname is offline
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Smile Heathkit AR13A Schematic ....PLEASE???? Help????

Hi!

I now own a good condition Heathkit AR13A solid state AM/FM Stereo Receiver.

The stereo indicator lamp for FM Stereo lights only as a VERY low amber glow. You can only see it at all by looking at the bare bulb. There is a type 49 bayonet bulb in the socket now. A 49 is rated at 2.2 volts at .040 amps.

Our suspicion is that this is the wrong bulb. The lamp responds properly when you tune in a stereo station, BUT, the amount of illumination is SOOOOOOOOOOO low, that the red jewel shows nothing.

Does anybody know what bulb is CORRECT, or maybe if the 49 is correct but the sensing circuit is not producing enough voltage and current?

I hope that someone can help please?

Sincerely,
Bob
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  #7  
Old 04-27-2014, 06:51 PM
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vinylisfinal vinylisfinal is offline
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i know ...old thread but i am in need of a schematic as well.... many thanks in advance.
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  #8  
Old 04-27-2014, 07:41 PM
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woodj woodj is offline
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Some of the older AR series used either #44 or # 47 bulbs (can't remember which). In some, the stereo bulb was in the resistive circuit to ground of the stereo switching transistor and was prone to burning out rather frequently.
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  #9  
Old 04-27-2014, 08:12 PM
ecluser ecluser is offline
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I've just uploaded to the AK database the partial schematic that I have for this receiver. The tuner section is missing unfortunately.
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  #10  
Old 04-27-2014, 09:05 PM
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fred soop fred soop is offline
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Quote:
Originally Posted by ecluser View Post
I sent you a PM for the schematic.

The original power transistors are 2N2147 and the bias is provided by germanium diodes 1N2326. Replace the transistors by silicon ones, like the easy to find 2N2955, and the diodes by silicon ones (1N4002 for example)
Without seeing the actual circuit, this is probably similar to a Fisher 600-T, TX-300, or a number of Fisher console amplifiers. While you can convert to silicon transistors, you will probably need to modify the bias circuit because silicon transistors run at approximately 0.7 volts Vbe vs 0.2 volts for germanium. Does your circuit use 2 or 4 transistors per channel?

Also, converting to silicon, you will likely convert from PNP to NPN which is actually trivial. Just reverse all the power supply connections to the power amplifier.
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  #11  
Old 04-28-2014, 12:35 AM
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Trio Trio is offline
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But there are plenty of decent silicon PNP types, so the extra burden of changing polarities can be avoided.
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