Kenwood KR-9050 is Finished -- A Few Pics

Endzone

Endzone

Active Member
Thanks for all advice and input regarding this repair. This was the first of these types of units I've ever done. I am a radio technician. Getting the schematic from Vintage Audio Manuals was the right thing to do. I'm glad for this web site too were folks of common interest can enjoy vintage audio gear. I'm just going to let her warm up for the next few days and break in. The AM/FM tuner sounds good. Next step is to hook it up to a pair of Marantz Imperial 6 speakers I bought on Craigslist for $10. Thanks for all the good advice.


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Display lights are actually a little dimmer than in this picture and indicator lights are a darker red.​
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Unit is finished​
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Setting bias voltage on final output transistors for 40mV​
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I forgot that that receiver uses the 2SC2607 & 2SA1116 outputs. Rare stuff.

Ditch those alligator clips! Get some minigrabbers!
 
EchoWars said:
I forgot that that receiver uses the 2SC2607 & 2SA1116 outputs. Rare stuff.

Ditch those alligator clips! Get some minigrabbers!
Click to expand...

Do you think I'll pay a price down the road for not changing those P/S filter caps? This unit was made in '79 I guess.
 
Endzone said:
Thanks for all advice and input regarding this repair. This was the first of these types of units I've ever done. I am a radio technician. Getting the schematic from Vintage Audio Manuals was the right thing to do. I'm glad for this web site too were folks of common interest can enjoy vintage audio gear. I'm just going to let her warm up for the next few days and break in. The AM/FM tuner sounds good. Next step is to hook it up to a pair of Marantz Imperial 6 speakers I bought on Craigslist for $10. Thanks for all the good advice.
Click to expand...

That's a beautiful Kenny. Next thing you'll be looking for bigger speakers to take advantage of the full 200W on tap. :thmbsp: That said, I bet you'll love the Imp 6s.

And listen to EW - mini-grabbers are wonderful. Rat Shack sells some that slip onto the end of standard multimeter needle probes.
 
Sam Cogley said:
That's a beautiful Kenny. Next thing you'll be looking for bigger speakers to take advantage of the full 200W on tap. :thmbsp: That said, I bet you'll love the Imp 6s.

And listen to EW - mini-grabbers are wonderful. Rat Shack sells some that slip onto the end of standard multimeter needle probes.
Click to expand...

Thanks Sam. I know you like this model.
 
Endzone said:
Do you think I'll pay a price down the road for not changing those P/S filter caps? This unit was made in '79 I guess.
Click to expand...
What is their physical and electrical size, and how are they electrically connected? There may be an inexpensive & excellent replacement.

Edit: 10,000µf 90V, so a 100V cap is required. But still need to know the physical size and electrical connection method. Looks like a 50mm diameter...
 
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EchoWars said:
What is their physical and electrical size, and how are they electrically connected? There may be an inexpensive & excellent replacement.

Edit: 10,000µf 90V, so a 100V cap is required. But still need to know the physical size and electrical connection method. Looks like a 50mm diameter...
Click to expand...

Here is a pic that is the actual size, so they must be 50mm. At the bottom there are kind of square tabs (terminals) that are soldered directly into the PCB. They are all Elna, so I'm guessing they are original. 2 look different from the other 2 though.


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Thanks to all for the compliments.
 
This isn't something you can guess at. Measure the caps (50mm ~ 2").

If they are solder-tab caps, you're going to have a rough time finding replacements. Michael Percy Audio sells a 10,000µf 100V Nichicon in a 50mm diameter, but it's 100mm tall (a hair under 4"). If those are too tall, I got no suggestions.
 
Glad to hear you got your KR-9050 back up and running! That is one very nice receiver!

Enjoy the music!
 
lha1992 said:
Glad to hear you got your KR-9050 back up and running! That is one very nice receiver!

Enjoy the music!
Click to expand...

Thanks! It sounds great! I just listened to a Chicago 17 album (track 10) with a good trumpet section towards the end of the song. It just sounds great running through those old Marantz Imperial 6 speakers. I don't hear any distortion driving it through AUX and also using the FM tuner. I'm really happy with it. It does have a twinge of that "vintage" smell, and you know what I mean. I thought about hosing down the componenet side of the PCBs, but I'm not sure I want to do that at this point. I guess that's it.


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Here is a shot of the main caps from my kr-9050
1.620 dia 4 inch length. center to center lug spacing .545
After I had replaced my caps, I could not notice any real difference in sound.
At 50 not hearing so good. So my opinion may not be a good one.
Used sheet copper to fab solder lugs on new caps.
Old caps were hard to get unsolder, Copper lifts off circuit board real easy.

As i look at the picture of your Endzones 9050, Looks like the main lamps shadow the top of the meters. My 9050 is the same way.
Still looks real nice and glad you got it up and running.
 

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