I bought this amp a while ago. Never had a Kenwood before so I figured this would be a good start. I am far from an expert and any criticism is welcome.
The good:
Both channels work, the owner stated the right channel would cut out after a few mins. Cleaning all controls fixed the problem.
Fuses look to be the correct value and very old.
The Bad
Enclosure might have seen some weather (heavily corroded and paint flaking off), I wasn't planning on posting this so didn't get a lot of before pics. but have some.
Transformer has been replaced.
Recapped some time ago but done poorly, a few burnt traces. 4 that I have found so far.
Face plate was sanded? Not sure I understand this one. I bought a new one that has some scratches and dings but wasn't sure when a better one would appear on ebay.
Have some pics, more to follow.
The good:
Both channels work, the owner stated the right channel would cut out after a few mins. Cleaning all controls fixed the problem.
Fuses look to be the correct value and very old.
The Bad
Enclosure might have seen some weather (heavily corroded and paint flaking off), I wasn't planning on posting this so didn't get a lot of before pics. but have some.
Transformer has been replaced.
Recapped some time ago but done poorly, a few burnt traces. 4 that I have found so far.
Face plate was sanded? Not sure I understand this one. I bought a new one that has some scratches and dings but wasn't sure when a better one would appear on ebay.
Have some pics, more to follow.
Current State
Current state recapped. I have the pics from before on my work laptop, so when I get that ill post before.
Current state recapped. I have the pics from before on my work laptop, so when I get that ill post before.
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Painted the chassis and transformers. Normally I would never do that, but I had to get ride of the rust and corrosion so after words needed protective primer and some paint. Under chassis was not painted.
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Nice work! I have a parts unit here. The transformers are available, but shipping would be expensive.
I would be interested in a amp board and a control board if you have it. Those are the boards that have the burnt traces. If so send my a PM and we can talk price.
There a pair of transistors. Darlington I think and they have caps and resistors in them. kind of different way of doing things. They are hard to get but are reliable from what I've read.
it may be easier to ebay a parts unit that is better cosmetically and use both to make 1 good one. Then ebay the leftover unit for remaining parts
True. I've been looking. Hopefully one shows up. These aren't the most common. In the mean time i have been looking for ways to repair burnt traces. So far using hook up wire is the only reasonable solution. Just want it to look good and be reliable.
if there is any trace left, scape the laquer off and solder 30 gauge bare hookup wire to the bare trace. if the trace is wider use 24 or 2 lengths of 30 gauge. works well for me
will post more updates as soon as parts get here. Figure well the diode boards are accessable ill replace the resistors ,transistors and diodes on them. Over kill I know but who cares.
An update, will post pics soon. I got the amp together. Works great!
I ended up replacing most things on the diode board. I measured the rectifier diodes and 1 of them seemed to be leaky, allowing some current through? I have never seen that before. So I replaced them all (DZ 1 - 8) with all (UF5408). I had an equivalent transistor on hand from a past project so I replaced that (Qz 2) with (KSC2690). I replaced a few resistors on the board as well, all though none of them tested bad. I replaced all filter caps again, ughh I soldered and unsoldered the new caps a few times and thought the heat from that wasn't good for them so just in case bought some more, but I was able to find some 40mm caps from Digikey I'm surprised I didn't find them the first time and they weren't to expensive either 11$ if I remember correctly and no adapter needed, just soldered some heavy stiff wire for legs and its nice and solid.
I forgot I needed to replace the treble pot, I even bought the pot and simply forgot. The treble pot is detented and the bass pot is not. I bought a treble pot from Ebay for the 9100 and it is not detented so I assume that they are not suppose to be. I also fixed the bad solder joints with a bit of wire, not ideal but solid reliable fix.
I ended up replacing most things on the diode board. I measured the rectifier diodes and 1 of them seemed to be leaky, allowing some current through? I have never seen that before. So I replaced them all (DZ 1 - 8) with all (UF5408). I had an equivalent transistor on hand from a past project so I replaced that (Qz 2) with (KSC2690). I replaced a few resistors on the board as well, all though none of them tested bad. I replaced all filter caps again, ughh I soldered and unsoldered the new caps a few times and thought the heat from that wasn't good for them so just in case bought some more, but I was able to find some 40mm caps from Digikey I'm surprised I didn't find them the first time and they weren't to expensive either 11$ if I remember correctly and no adapter needed, just soldered some heavy stiff wire for legs and its nice and solid.
I forgot I needed to replace the treble pot, I even bought the pot and simply forgot. The treble pot is detented and the bass pot is not. I bought a treble pot from Ebay for the 9100 and it is not detented so I assume that they are not suppose to be. I also fixed the bad solder joints with a bit of wire, not ideal but solid reliable fix.
Some pics. Tbh would I do it again the answer would be no, not this amp, especially one that was abused as much as this one was, but I'm glad its working and looking good now. Been listening to some Soul Button for a good hour now.
Just need some screws and a good cleaning then its off to Ebay.
Just need some screws and a good cleaning then its off to Ebay.
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