KR-9600 Restoration Info

The parts with the C suffix (as you have) are ECB same as the originals. The datasheet shows the non C part in the photo, but if you look at the top under features you'll see them mention about the C suffix.
 
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I was considering mounting the 3 new resistors vertical with either small screws or maybe pop rivets .Its the gauge of the jumper wire I'm also considering .I have 20 & 16 . I'm thinking 20 as the 16AWG is kind of big for the board . Any suggestions ?kr9600.jpg kr9600II.jpg
 
I'd use 20 awg. Are you using solid core or stranded? If solid core it helps to wrap the wire 5-6 rotations around a drill bit or something similar in diameter to the pins and then fit them on and solder them up.
 
I ended up using both ,the stranded I liked better for connecting to the board traces . On to the amp boards .
I already have done Qe1&Qe2 with the ZTX694 but I will check their hfe. I notice Qe3 is also replaced with the ZTX694 but no mention (that I could find) about Qe4&Qe5 that are also 2SC1775's . It doesn't look like they were replaced in the photo , leave Qe4 &Qe5 alone? I notice some people used KSC1845 here .
 
Thanks, I saw that on another thread . So there are 3 options for Qe1 through Qe5 , KSC1845, 2SC2240, ZTX649. I have all three on hand . I'm leaning towards the 2SC2240. I'll have to see which one is the" toughest " Any suggestions ?
 
I pulled Qe1 & Qe2 from my working unit and I used ZTX696 which appears to be a 180v of the ZTX649
 
I'm getting 12mv for the DC offset with ZXT696. What I didn't notice that Ft is lower (70Mhz) than the ZTX 694 (130Mhz).
 
Almost back together . I have it driving a pair of Bose 901 VI . Sounds good considering the room and 901's no problems so far. I didn't do the Triac ,with all new caps shouldn't the AC switch be OK ? With old leaking caps doesn't the unit draw more current to try to get the voltages ?20180311_131327.jpg 20180311_131405.jpg
 
I didn't do the Triac ,with all new caps shouldn't the AC switch be OK ? With old leaking caps doesn't the unit draw more current to try to get the voltages ?View attachment 1136603 View attachment 1136604

I have worked on several of these - I have never seen one with what I would consider to be a "healthy" power switch. They take a beating and often fail. If the regulator board shows heat discoloration you can be certain that the unit has seen a lot of use and that the power switch is probably in similar condition.

It is a fairly simple operation to disassemble the switch, rotate the body 180 degrees relative to the toggle assembly, and reassemble in order to utilize the unused set of contacts. Do this and add a triac and it should be good for just about ever.
 
Makes sense I'm going to do it . I have the triac but I also have some CL-70 that I used on Fisher tube stuff and a Marantz 18 . The triac is a more robust and seems to act more like switch with the CL-70 a resistor . Thanks
 
The left side little contact push fell out of the switch. I think I found it but its different from the right side see picture. Does that look correct ? 20180314_130317.jpg
 
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If it looks more or less like these then you're OK. If one spring is longer than the other use it for the AC side of the switch - I think it was done to prevent "bounce" which would cause additional arcing.. Use the weaker spring for the other side of the switch - I think it's for a muting circuit. If you're adding a triac I wouldn't sweat it.

I've used a tiny dab of lithium grease to hold those little buggers in when reassembling the switch.

How bad was the AC side rocker?
 
It had some signs of arching . I'm still not sure if the piece I found is correct . Its cone shape and the stem which fits in the spring is smaller in diameter.Its a looser fit than the other one , maybe that's why it fell out ? don't know But would be the chances finding something on floor that fits . Thanks for quick reply
 
I have an original used KR-9600 power switch - I'll take it apart and see what gives.
 
Thank you ! , I have switch back together checked with the ohm meter and its working .
Maybe the Conehead can take more heat ? Shouldn't matter now with the triac right?
 
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Done, the triac mod went well . I used the hand drawn schematic with two 2 connections on the triac MT2 .Hooked the KR9600 back to the 901's and it plays fine . And this time I remembered to connect the 901's EQ to the Kenwood it a made a big difference :). I was actually surprised at how good bass response is . Thanks again for all the help
 
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