Kenwood KR-8010 cleanup and restoration

Junfan

Active Member
I picked this up earlier in the week along with a pair of Dynaco A25s with the plans of it being the center piece of my office setup. I have been listening to this the last couple days. It does not get warm although I will confirm everything is fine before it goes back together. It has some paint spatters on it and is very dirty inside and out. It has obviously been apart before and the volume and both tape switches need to be cleaned very badly because I can make the left channel come and go at will. Any recommendations would be great and does anyone have a service manual download handy?

Time to hit up bartertown or something since I cannot be without my office system while I restore this unit. I am trying to stay out of the Pioneer camp for a temp unit since they seem to cost a little more than some of the others. Going to look for one of the following or maybe a lower powered Kenny in the meantime.

Technics SA-500
Technics SA-505
Technics SA-600
NIkko NR 719

Thanks for looking and hope you all have a wonderful Friday.
 

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More pics.
 

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Last of the pics. I think before I take this apart I also need to put it in my main listening space instead of the Behringer. I think this may sound better than it and if it does I will have to find something older for my main system.
 

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oh yea

Beautiful receiver, does everything well. Will follow your rebuild as I hope to keep mine running :music:along time.
 
I took the time to check the dc offset and document a little more the receiver. I know for sure it has been apart since left two transistors are as follows. I full rebuild appears to be in order and I assume I should search for matched sets for both sides?

I am picking up a Technics SA-600A saturday since I feel like this unit is going to be down a couple months. At that point I will tear into and have tons more pictures and probably many questions.

SYL
ECG88
8339

P312
ECG87
8628

NEC
2SD555
S85A

NEC
2SB600
S87A
 

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Last picture

The DC Offset measured 4.4 on the left channel and 1.4 on the right as seen in the pictures.
 

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I have not been inside my 8010 for many years, but I somehow remember mine having STK modules in it, not the transistors you show. I must be getting old and senile. This unit does not have a DC offset adjustment, just a bias adjustment which needs to be set at 50Mv. Your DC offset sounds good and is a product of the proper matching of the output transistors you have, some of which are not original apparently. The originals are TSB-600 and TSD-555.

You will really enjoy your Kenwood once it is all done. Mine has been a central part of my main system for years until I had my G-8000 rebuilt and I have always been more than pleased with it. At one point, I had it paired with my SX-1250 and it held its own in both sound quality and power. Good luck with your project.
 
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Thanks for the info KingBubba. I hear that these output transistors are almost impossible to get and now I am not sure what to do.
 
With the DC offsets you listed, I would leave them alone. The heads are stripped on some of your screws and getting them out might be hell.
 
Thank you sir. Careful shoveling all that sunshine in Florida.

The right channel cut out today and when I move the vol knob it comes back sometimes. I just turned it off and time to tear into it. I want to save this receiver.
 
Yesterday afternoon while I was finishing another project, Overnight Sensations MTM, the right channel cut out and when I play with the volume knob it comes back. I got pissed off and took it out of the system completely and now it will start coming apart this weekend. I am more than a little frustrated with this but nothing I can do about it and surely not willing to toss in the towel yet.
 
If you get it back by playing with the volume knob then it probably needs the volume pot cleaned with deoxit
 
Thanks yea planned that and figured that was the issue just frustrated with the overall shape of this unit. Of course pictures on the internet make it hard to judge.

If you get it back by playing with the volume knob then it probably needs the volume pot cleaned with deoxit
 
Offset looks fine.

The original outputs are 2SB600 and 2SD555. Out of production for many years, and a couple of the most used and most counterfeited transistors ever. But the On-Semi MJ21193G and MJ21194G make fine replacements and are superior in a number of ways.
 
Thanks man, I was just being pissy this morning before coffee because I want to use my new Kenwood instead of fix it first. Oh well I knew going in this was a possibility.

Offset looks fine.

The original outputs are 2SB600 and 2SD555. Out of production for many years, and a couple of the most used and most counterfeited transistors ever. But the On-Semi MJ21193G and MJ21194G make fine replacements and are superior in a number of ways.
 
Read the Deoxit sticky on AK and then get some. Take your time with that pot. Chances there are not replacements available any more. You may be able to get into the pot without removing it from the front panel. Do the pot and switches with Deoxit and follow with Gold. Most of the time this takes care of the kind of issues you described and does not take too long.
 
I stepped away from this project for a while and did a few others. I have rebuilt a Yamaha CA610II, a pair of Lepai amps and several speakers. I think I am now ready to tackle this. I am going to start pulling a spreadsheet together. I am thinking a full recap is in order. The others have turned out great and especially the Yamaha. This is the long term amp staying in my lab/office area and will be paired with the AR2AX I restored recently.

Thoughts?
 
I been looking through the Kenwood forums for recaps and I really do not see as many as say the Pioneer, Sansui or Yamaha forums. I feel like caps in this unit are probably out of spec but am wondering why I do not see as many of these type of restores in the Kenwood Trio forums.

The goal here is to preserve my receiver and I feel like a recap and new transistors would be fun and rewarding. Do you guys normally recap an older unit like this? I have the services manual which has the screw size for the transistors so I can get those from McMaster. In fact the manual has all the cap sizes and basic location information.

Last but not least at what point do you do film caps instead of electrolytics?
 
Dunno why you don't see more Kenny's getting redone. May be because the Kenwood models were cheaper and considered throw-away. If that's it, I consider it unfair and a mistake.

Some Kenwood receivers were pretty easy and others a real challenge to recap. Can't tell you where this one comes in, but there's one way to find out.

Any cap from about 2.2µf down I try to replace with a film cap. That generally means a really small film cap in order to fit, which means a WIMA or a stacked film cap.
 
I started working on this yesterday and this AM. I took it to my air compressor and used circuit board cleaner on it. I now have it on my bench and am finishing the process with qtips and such.

I am still trying to figure out how deep I am going to go on recapping this unit.

Enjoy!

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