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Kenwood KR 9600 Rebuild

SPL db

SPL db

It's all about the music!
Subscriber
With the aid of Echowars (and anyone else who'd like to join in),
I'm going to rebuild a KR 9600 that has power, but no audio...

There is no relay click when the unit is powered on... EW wanted
me to report what voltage readings I get on pin 1/10/& 5...

On pin one (both channels) I get +69V - pin ten (both channels)
gives me -69V - pin five (the output) on one channel is +69V and
on the other channel I get +53V.

EW states I should have as close to zero volts on pin five... looks
like there's some troubleshooting to do! :D

Does this sound like bad output modules or a problem with regulation?

Thanks!
Scott
 
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The only way that there could be that kind of voltage on Pin 5 is if the module is toast. So it appears to be a rather short project...or a rather long one...

The IC could be replaced with a PC board and discrete parts. Maybe I could get ilimzn to render his opinion...
 
Here is the 'equivalent' circuit...
 

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Well if that don't beat all!

I figured the module was toast with that high of reading on the output... :(

Scott
 
Hey! Wait a minute! You told me that pin five was the output...

According to the first schematic, the output is pin SIX!

Pin six is at zero volts on my unit!

Are we back in business? :yes:
 
Oh, nevermind... I see it now, I was looking at the whole picture being the power module... :dammit:

Pin five is the output of the IC...

Time for me to go to bed! :D

Scott
 
Yeah...it can get confusing, but the pin we are concerned with is Pin 5 of the IC chip...or Pin 6 of the driver board.

It is certainly possible to replace the IC with discrete parts..the question is...can it be done neatly?
 
Another question would be how it would be tied to the heat sink?

Scott
 
Those damn output chips!

I have owned a few 9600's over time. The original one I bought from the Navy Exchange on Guam back in 1979.

It survived my time in the Navy(in the barracks where everyone used each other gear), I came home for 2 yrs and used it for a wedding and several outdoor parties with kabuki speakers(Sansui SPX9-II's or something like that). Went back in the servce and let my younger bro borrow it at his rental with 4 others living there(think "Animal house"). and took it back when I left the service for the last time in 84.

It only died when I had a speaker project in mid stream(wires all over the floor) and a friend of mine stepped on some wires and shorted out the chnl. I had abused the amp in every other way(high-power/heavy bass) and nothing affected it.

My only real problem on my original 9600 was the power switch. switch would turn off the audio, not the power. So I used the kitchen light switch(switched wall outlet) to turn unit off and on for use.

The last unit I got was for nostalgia purposes. By this time I was into high end and the 9600 did not fit the bill, tubes took over for me.

The KR-9600 is bullet proof other than open/shorted connections. I would recomment this rcvr for some one wanting a GREAT tuner section, ballsy amp, but have someone replace the signal caps to help out the overbearing midrange!!!

Ron
 
Well if anyone has any output modules for a Kenwood KR 9600
they want to sell... I'm all ears!

Scott
 
Scott,
You would have a easier time buying another 9600 than finding those output modules. Check e-bay for 9600's and see what they are going for. maybe find a unit that is half dead and part it out.
ROn
 
spkrman57...

You're absolutely correct... I know where I can get a NOS module
but the guy wants $120 for it!

I can add a few dollars to that and get a whole working unit!

Just keeping any and all options open! :thmbsp:

Scott
 
What's wrong with turning it into a project where the original IC gets replaced with discrete parts?

I'll have a schematic in a day or two...

EW
 
No...different module..TA-200W for the 9600 and a TA-100W for the 9100, and the pinout is different too.

Plus, Nasta already gave me a circuit for the 9100 a few years ago. :thmbsp:
 
EchoWars said:
What's wrong with turning it into a project where the original IC gets replaced with discrete parts?

I'll have a schematic in a day or two...

EW
Click to expand...

No problem what-so-ever! Good candidate here!

This thing's kinda homely looking, but I've always had good luck with mutts!

Bring it on!

Scott
 
Not the same module, the 9100 one (TA-100WA) has one transistor pair in the output. I've corresponded with EW on this subject before and devised a replacement for the TA-100WA, and since he provided the internals of the TA-200W we're working on a discrete replacement (or rather, he is, since I'm on the other side of the Atlantic, I'm just giving him ideas and nagging ;) ). The solution used for the TA-200W would work for the TA-100WA assuming only one pair of output transistors is used, also one resistor may need to be changed.
 
ilimzn, look this over when you have a chance...

Edit: Rev. 1.3
 

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You guys are totally AWESOME!!!

Looking at one IC power amp chip, reverse-engineering its specs,
then re-engineering a discrete replacement.

Makes my replacing carbon comps with metal films look like kindergarten sandbox creations...

:yes: :D :thmbsp: :naughty:

Bob
 
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