Hello,
I'm new to the forum. I have a question regarding repair of a vintage receiver. Is this the best forum for that?
My question: I recently purchased a vintage KLH Model 52 receiver (from the 1970's) at a thrift store. I got it for 35 bucks; and despite needing some new lamp bulbs, it is in pristine condition and I'm looking forward to getting it cleaned up. However, as I've tested it I'm seeing it has a few issues that I was hoping to get some advice on. I attached a couple pictures and I have a copy of the service manual which has parts list, schematics, etc. for reference if that is helpful.
1. The power switch for these KLH receivers is basically a switch built into the volume potentiometer--so when you turn it all the way down it's supposed to "click" and turn off. The first problem is the receiver volume works fine... but when you turn it all the way down there is no "click". Nothing seems to be wrong with the volume other than the off doesn't work. Has anyone run into this? I'm wondering if the only option is to replace it? If so, any suggestions on where to buy the part?
2. The second problem (and this is the one I'm a little more worried about) is that when I plug in headphones the left channel is significantly louder than the right channel. Both come through clear... but one is much louder than the other. Any ideas? I was wondering if maybe a recap would help? thoughts/suggestions... ideas on stuff to test or try? Could it be anything else's? I read online some people had this issue and it was the volume pot. Seems unlikely to me.
3. The tuner works fine.... but when I tune into an FM station the "stereo" lamp doesn't turn on. I'm hoping it's just a bulb issue. Any other reason it wouldn't register "stereo"?
While I'm new to the forum and repairing vintage receivers, I do have electronics familiarity (I've built/repaired guitar tube amps); also I have an oscope, if that is useful in diagnosing/fixing.
Thanks for any input you can offer!
Daniel
I'm new to the forum. I have a question regarding repair of a vintage receiver. Is this the best forum for that?
My question: I recently purchased a vintage KLH Model 52 receiver (from the 1970's) at a thrift store. I got it for 35 bucks; and despite needing some new lamp bulbs, it is in pristine condition and I'm looking forward to getting it cleaned up. However, as I've tested it I'm seeing it has a few issues that I was hoping to get some advice on. I attached a couple pictures and I have a copy of the service manual which has parts list, schematics, etc. for reference if that is helpful.
1. The power switch for these KLH receivers is basically a switch built into the volume potentiometer--so when you turn it all the way down it's supposed to "click" and turn off. The first problem is the receiver volume works fine... but when you turn it all the way down there is no "click". Nothing seems to be wrong with the volume other than the off doesn't work. Has anyone run into this? I'm wondering if the only option is to replace it? If so, any suggestions on where to buy the part?
2. The second problem (and this is the one I'm a little more worried about) is that when I plug in headphones the left channel is significantly louder than the right channel. Both come through clear... but one is much louder than the other. Any ideas? I was wondering if maybe a recap would help? thoughts/suggestions... ideas on stuff to test or try? Could it be anything else's? I read online some people had this issue and it was the volume pot. Seems unlikely to me.
3. The tuner works fine.... but when I tune into an FM station the "stereo" lamp doesn't turn on. I'm hoping it's just a bulb issue. Any other reason it wouldn't register "stereo"?
While I'm new to the forum and repairing vintage receivers, I do have electronics familiarity (I've built/repaired guitar tube amps); also I have an oscope, if that is useful in diagnosing/fixing.
Thanks for any input you can offer!
Daniel
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The switch-on-pot can be very difficult to source. In a few chassis you can get the pot out, take the switch off, and find the jumped-off spring, or bent lever. But if it is stuck ON, the best path for now is to plug it into a switched power strip.
Stereo lamp can be many things. Put a DC voltmeter on pin 3 of the MPX board. It probably goes over 10V for bad signal, down to very low voltage when the stereo detector is happy. Ah, it won't pull-up if the lamp is blown. Tack a 10k resistor across the lamp to pass enough current to move your meter. Or put an LED and a 2k resistor in series across the lamp, cathode to MPX pin 3.
The headphones could be a dirty jack or a blown channel. This thing is old and was not KLH's best work when new. Try the speakers outputs.
Stereo lamp can be many things. Put a DC voltmeter on pin 3 of the MPX board. It probably goes over 10V for bad signal, down to very low voltage when the stereo detector is happy. Ah, it won't pull-up if the lamp is blown. Tack a 10k resistor across the lamp to pass enough current to move your meter. Or put an LED and a 2k resistor in series across the lamp, cathode to MPX pin 3.
The headphones could be a dirty jack or a blown channel. This thing is old and was not KLH's best work when new. Try the speakers outputs.
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