Kenwood KR-9600 Extra AMP Board Question

Hello all,

Quick question. I didn't see this in any forum, so if there is one that discusses this please fwd me to it.

I had acquired another KR-9600 off ebay for $50. Unit was being sold for parts only as it wasn't producing any sound. Seller had it up for $180 or best offer. Shot him $50, he took it. I got it in and yea.. it needs some work. I plugged it in and turned it on, the relay's didn't click. I opened it up, 2 fuses were missing on the power supply(Picture 4,Fuses F1 and F2)? Any ideas? The main fuse holder underneath the unit is broke(i'm waiting on a new one to come in).

But my main question is what are these extra X07-1610-10 Sanken boards that are piggy backed onto the main amp boards? This one on the right has it's wires severed from the main amp board(picture 3).

My other KR-9600 doesn't have these extra boards in it so I was just curious to what purpose they serve and is this unit an older model than the ones that don't have these boards?

Thanks.

I do believe they are, at least in part, a current foldback device. I've never seen a schematic for one, but I do have a parts layout and a good pic of the solder side of the board (should someone decide that they'd like to rev engineer it).

Thanks Glenn. Thats interesting. I was thinking it was like a early model like from 1976, then maybe they did a design change for the later production years? All the pics ive ever seen on 9600s dont have this board.. I got curious..

I've seen a couple of them. Documentation would be nice, but it seems to be non-existent.

I have 2 parts units with those boards attached to the heat sink etc. Looks like to me a last mod to help protect the output chips. never found docs from Kenwood yet ..
I sold a few units with those boards in them also.

John M