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Author Topic: Kay 708 amp repair  (Read 171 times)

RadioRay

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Kay 708 amp repair
« on: August 17, 2019, 11:54:42 AM »
Hi!  I recently picked up a Kay model 708 amplifier.  I believe this was one of the first SS amps.  Problem I am having is the vibrato thumps all the time and the controls  have no effect.  I have the schematic for the amp.  Not sure where to start on this.

Thanks for you assistance.



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RadioRay

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Re: Kay 708 amp repair
« Reply #1 on: August 19, 2019, 03:59:13 AM »
Hi,  Somehow I can't see my first post so I am starting over.

I have a Kay model 708 amplifier, first question - has anyone had any experience with this amp?  its the big brother to models 704.  It was the top of the line for Kay early solid state amps according to the Kay literature I have seen.  The vibrato just thumps loud with no control.  Any advice on finding transistors for this puppy?

Your comments are appreciated.

Ray.

I am adding pictures of the amp and a schematic and BOM.


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phatt

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Re: Kay 708 amp repair
« Reply #2 on: August 19, 2019, 05:29:54 AM »
Yes I could not load your posting before  :loco
Seems to be working now.
So post the schematic and other pics :tu:
Phil.

RadioRay

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Re: Kay 708 amp repair
« Reply #3 on: August 19, 2019, 08:28:10 AM »
Hi, I'm going to try it again
Here are the pictures,
Ray

RadioRay

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Re: Kay 708 amp repair
« Reply #4 on: August 19, 2019, 08:33:12 AM »
Hi, I'm splitting up the photos.


joecool85

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Re: Kay 708 amp repair
« Reply #5 on: August 19, 2019, 09:23:47 AM »
For some reason, your images were causing the threads to break.  SMF didn't agree with them.  I have removed the images causing the issue and turned on some features in SMF that should prevent this from happening again.  Sorry for the trouble, but welcome aboard!
Life is what you make it.
Still rockin' the Dean Markley K-20X
"New" amp: Fender Frontman 25 DSP (FM25DSP)
thatraymond.com

Jazz P Bass

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Re: Kay 708 amp repair
« Reply #6 on: August 19, 2019, 08:30:07 PM »
There are more than a few germanium transistors in that amplifier.
Prove that they are bad before replacing them.

I would think 'capacitors' in a non functioning Tremelo circuit.

 

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