Model Nine GX / KR9000 Restoration and Recap

[w1jim]

Ta-Da!
All finished, put back together and ready to be put into the rotation.
The wooden case has it's marks (especially on the rear edge) and the top looks like it has some rust but that's only from the edge with the flash making it look far worse then it actually is - those things don't bug me much.

 

[SicMan]

Jim;
Cosmetics do not make it sound better. That can be done at another time.
Great thread.

Good Luck with it.

John M

 

[Joe Kraft]

W1jim, You don't by chance have a service manual for your Model Nine GX do you? I am trying to resurrect a nice looking unit and can only find a Model KR9000 on Hifiengine. Some say that there are not much for differences but I am definitely finding discrepancies between my GX unit and the KR9000 manual. Thanks for any help you can get to me.

 

[w1jim]

We

W1jim, You don't by chance have a service manual for your Model Nine GX do you? I am trying to resurrect a nice looking unit and can only find a Model KR9000 on Hifiengine. Some say that there are not much for differences but I am definitely finding discrepancies between my GX unit and the KR9000 manual. Thanks for any help you can get to me.

Well, it’s only been 7+ years - and despite my turning over much of my collection I still have the Kenwood.

I’m out of town for work but when I get back I’ll see if I have the Nine GX manual in my archives.

 

[Joe Kraft]

We

Well, it’s only been 7+ years - and despite my turning over much of my collection I still have the Kenwood.

I’m out of town for work but when I get back I’ll see if I have the Nine GX manual in my archives.

That would be great thanks so much.

 

[w1jim]

Sorry, no Nine GX manual in my archives.

You should start a new thread asking for advice on any issues you encounter.

 

[aileenamegan]

No manual for free
https://www.manualscenter.com/manuals/kenwood/9gx-owner-manual.html

 

[w1jim]

No manual for free
https://www.manualscenter.com/manuals/kenwood/9gx-owner-manual.html

That's the relatively useless users manual.
He's looking for the service manual.

 

[aileenamegan]

My fault - sorry. Have been too fast in clicking...

 

[onwardjames]

I missed this back in '12, when my buddy still owned his own Model 9 GX. Bought at a roadside yardsale for 7 bucks.

I always thought that thing looked amazing, and sounded very good. Would still love to own one.

Great job @w1jim !! You still got it?? EDIT - Yes, I see you do, lol.

 

[Joe Kraft]

To all interested in the Kenwood Model Nine GX, I did finally find a service manual for the GX and it is actually quite different from the Model Nine G manual. I have uploaded it to HiFiengine database so it is available. Thanks for everyones help. Let the repair begin!!!

 

[turboyam]

About that mini switch on the OEM power switch, wouldn't it be to feed the timer function?

 

[w1jim]

About that mini switch on the OEM power switch, wouldn't it be to feed the timer function?

Do you mean the slide switch?
Not sure how to answer your question as it’s been 7 years - though I do still have the Kenwood in my stable.

 

[turboyam]

Do you mean the slide switch?
Not sure how to answer your question as it’s been 7 years - though I do still have the Kenwood in my stable.

Actually, i was trying to answer your question!. You were thinking that it may have been for the speaker relay... Me thinks that this switch was feeding the timer motor?. Did not realise, this thread was so old!

 

[w1jim]

What’s old is new again.

I was doing some basic maintenance work on a friends KR11000G and admiring how pretty they are. This motivated me to pull the Nine GX off the shelf and put it back into rotation.

Well, it’s never that easy - I knew it needed the tuning dial restrung but I didn’t know why - apparently some mice had summered there and chewed up some wires (and that damn dial string).

I fixed up the few chewed wires and gave it an extremely thorough clean-up.

Adjusting the bias proved erratic so I put in a multi turn pot in place of the old one.

 

[w1jim]

Next while testing I noticed that the phono was noisy for the first minute or so.
These things never fix themselves, no matter how long you ignore them so I decided to replace the old inline package HA1457 opamps.

Those are “high voltage” opamps that are rated at 25 +/- (50 volts total) which is much higher than what’s on the market today.

I replaced them with Burr Brown OPA134PA mounted on a Brown Dog adaptor board.

I had to move some capacitors around a little to get them to fit.

Next issue was the voltage - the BB’s are rated at 18 +/- so I put some 220 ohm resistors across C107 / 108 to act as a divider network which dropped the voltage to a safe 15.5v on each rail.

One rail was actually a bit higher and required a 250 ohm resistor.

Now time to get it all back together for the final sound check.

I’m planning on pulling the Pioneer SX-D7000 out of the bedroom system and popping the Kenwood in there.

 

[aileenamegan]

Great job!