Project: Kenwood KR-8050

[armytanker]

this is great man, i have a 8050 i wanna do this to and this will really help. you're awesome. i have the kr 6050 through the 8050. maybe someday ill bite the bullet and get a 9050 to finish the collection.

 

[Sharpstik]

 

[shorage2000]

Nice job

 

[turboyam]

Great work! thanks for posting!. This series of receivers seems rare?.
In Canada, they are?.

 

[vinithing]

Yet another project for rebuild. The candidate is a KR-8050. Have rebuilt a couple of the KR-8010s in the last year or two. The KR-8050 is touch newer. It was found with a busted bass potentiometer, dirty, and knobs surfaces less than perfect.

Saw one of the years before and when this came available could not pass on the project. It is rated at 120 WPC.

Here is the list of replacements caps and the last page include transistors references that I changed. Hope you enjoy the upcoming posts. My hopes is that my journey will help someone or inspire someone to rebuild this set.

https://drive.google.com/open?id=1AZSy4BQUTGm87z0pOjih-D2gPhE3Hyk5

Would you be up for doing the same to mine and make a few bucks in the process?

 

[Super Noob]

Would you be up for doing the same to mine and make a few bucks in the process?

Not Really.
Am just a hobbyist.
My rebuilds are for fun and sharing here.
Have a full time job that pays the bills.

The 8050 is not an easy unit to work on... albeit much easier than 9G. If you knew how much time it takes to do all the work on this build the cost at $20/hr plus parts it would be well over $1K plus shipping. 60 HR.

There are few that would be willing to do the work and cleaning documented here. Most like to fix and do selective work.

I was a vintage stereo fan for 5 years and decided to take the plunge of learning electronics and doing recaps and repairs. The learning resources are out there for the motivated and with some persistence (and some tools) you can do it; however, the 8050 might not want to be one of the first few build you try.

Not sure why I am rambling here... good luck in finding a tech.

 

[DM_]

Not Really.
Am just a hobbyist.
My rebuilds are for fun and sharing here.
Have a full time job that pays the bills.

The 8050 is not an easy unit to work on... albeit much easier than 9G. If you knew how much time it takes to do all the work on this build the cost at $20/hr plus parts it would be well over $1K plus shipping. 60 HR.

There are few that would be willing to do the work and cleaning documented here. Most like to fix and do selective work.

I was a vintage stereo fan for 5 years and decided to take the plunge of learning electronics and doing recaps and repairs. The learning resources are out there for the motivated and with some persistence (and some tools) you can do it; however, the 8050 might not want to be one of the first few build you try.

Not sure why I am rambling here... good luck in finding a tech.

Recently acquired a KR-7050 and considering a rebuild. I'll make use of your parts list as a guide...Thanks! Did you happen to notice any bulging caps and overheating on the pcb in the Driver sections or Voltage sections on your 8050 before you started? I'm seeing some of that on this machine. Other than that I don’t see anything odd. The schematics aren't great and it's hard to find where to check for and what the voltages should be. I’ve worked on Pioneer gear but this is my first Kenwood. Also when I tried to inject a 1khz sine wave in to the AUX and look at it with the scope it went into protection and eventually blew the fuses. I can't figure that out at all. Did you encounter anything like that? Did you look at your output or just set it with the DMM? Any commentary would be appreciated.

 

[The Fuxtor]

Looks sexy as hell! Lighting is great! Reminds of the Onkyo MKII vintage series..

 

[vinithing]

Any idea where I can buy a replacemnt volume knob? Also if I were to do some of the cap replacements myslef do you know which ones tend to go bad more than others? Are there certain ones that would benefit and make a bigger difference from a peformace standpoint?
Cheers!

 

[Super Noob]

Recently acquired a KR-7050 and considering a rebuild. I'll make use of your parts list as a guide...Thanks! Did you happen to notice any bulging caps and overheating on the pcb in the Driver sections or Voltage sections on your 8050 before you started? I'm seeing some of that on this machine. Other than that I don’t see anything odd. The schematics aren't great and it's hard to find where to check for and what the voltages should be. I’ve worked on Pioneer gear but this is my first Kenwood. Also when I tried to inject a 1khz sine wave in to the AUX and look at it with the scope it went into protection and eventually blew the fuses. I can't figure that out at all. Did you encounter anything like that? Did you look at your output or just set it with the DMM? Any commentary would be appreciated.

Didn’t put it on a scope...

 

[Super Noob]

Any idea where I can buy a replacemnt volume knob? Also if I were to do some of the cap replacements myslef do you know which ones tend to go bad more than others? Are there certain ones that would benefit and make a bigger difference from a peformace standpoint?
Cheers!

1) Flea-Bay (might have to be patient or you might find it is common to other units which will widen your opportunities)
2) Caps are cheap. Caps are 40 years old. Go in once is my thought process. Yours may vary. Orange caps replace with film or UKL or UES caps. The others you can use UPW or more standard caps UKT or UKA.
3) Stock performance to spec should be more than enough for the common man - we are talking about vintage quality equipment.

 

[EC1]

A quick basic question, is the polarity of the old filter caps marked, did not see it here.

 

[Super Noob]

A quick basic question, is the polarity of the old filter caps marked, did not see it here.
View attachment 2062327

Black dot on lug is negative.

 

[turboyam]

A quick basic question, is the polarity of the old filter caps marked, did not see it here.
View attachment 2062327

On your left cap, on the picture, on the left, there is a grey stripe, with ( - )signs from top to bottom of cap.

 

[EC1]

See it, the black dot. Need to zoom in to see it. This is excellent post from you to share. Thanks.

 

[bartram423]

Yet another project for rebuild. The candidate is a KR-8050. Have rebuilt a couple of the KR-8010s in the last year or two. The KR-8050 is touch newer. It was found with a busted bass potentiometer, dirty, and knobs surfaces less than perfect.

Saw one of the years before and when this came available could not pass on the project. It is rated at 120 WPC.

Here is the list of replacements caps and the last page include transistors references that I changed. Hope you enjoy the upcoming posts. My hopes is that my journey will help someone or inspire someone to rebuild this set.

https://drive.google.com/open?id=1AZSy4BQUTGm87z0pOjih-D2gPhE3Hyk5

This is great , I have acquired one too.What is the best way to get the boards out to recap them?

 

[Super Noob]

This unit is not the easiest to work on…. I generally leave boards in during rebuilds. I cannot explain board manipulation, tie backs, blocking supports - it’s just based around minimal swinging of boards to preserve original wire wrap connections.

Best of luck.

 

[Sid Coleman]

Thank you so very much! Just got an 8050 and am bringing it back to life, this will be a great help.

 

[rulnacco]

Thanks so much for this! I picked up an 8050 a few months back. It's working really well at the moment, but obviously given its age a bit of refreshing in the near future can't hurt. This post is going to be a super resource--as is the parts list, super helpful. Really appreciate it!