B-2101 repair project.

BigElCat

Mmm Hmm
The back story. I bought this amp on Etsy. They said it worked fine, but it was reluctant to come out of protection. It would turn on, but sounded rather lame. Eventually, it wouldn't turn on at all.

I put it on the shelf for a while. I tried the set the Bias, and blew out a Sanken.

http://audiokarma.org/forums/index....-missing-on-board.790817/page-3#post-11075220

So I'm starting the disassembly. This will be slow, I haven't ordered any parts.

Thought I'd post a few pics.
 
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Had to take the top and bottoms covers off.
The F-4619 board comes out with the big heat sink attached.
I'm only going to work on the right channel for now.
WIN_20180102_03_50_00_Pro.jpgWIN_20180102_03_55_23_Pro.jpg

Time to break out the Hakko and desolder bulb.

DSC00440.JPG DSC00441.JPG DSC00442.JPG
 
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I want to replace kVR3 and kVR4 with Bourns multi-turns.

The are 1K ohm, but no wattage rating is given in the service manual.

Any suggestions ?

This is for me...I think I'll order from digi-key.
 
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I'll order caps individually. Shall I use Panasonic FCs for the Power Amp Board ? IIRC, that's what I did in my AU-X701.

What about this big resistor that was smoked up when the Sanken blew ?

WIN_20180103_15_34_22_Pro.jpg
WIN_20180103_15_35_04_Pro.jpg

It should be okay, don't you think ?
 
The Panasonic FCs only have a 1000 hour life. That seems really low.

Digikey only has them to replace this one.

WIN_20180103_15_41_38_Pro.jpg

I'll need to substitute a Nichicon or something for the 10uF 35v ones. Or shop somewhere else.

I appreciate your help guys. I have to go to work now...I'll check back tomorrow.
 
I made the first 2 adjustments for each channel...I'm within range and steady.

The 3rd adjustment is 2-2 step 3. I'm on the test point F-4619...ground pin and hot (out). I get no reading at all.

Same thing on the right channel. No reading at all. I've verified I'm on the correct pins. I've moved kVR-2 just to see. No response. No voltage.

I did not have a dead short or do anything real stupid...that I can see.

Even though I could not get a reading between the ground pin and the hot (out) pin, I moved on to the 3rd adjustment.

I was on the hot (out) and emitter (out) pins...adjusted kVR-3 to be within range. It was steady at 6.8mV. And then a flash.
 
I did 2-1; steps 1 and 2

Then 2-2; steps 1 and 2.

Then on 2-2; steps 3 and 4....I got no response from the DMM while trimming kVR2.

It must have been reading all zeros, with no response when I moved the VR.

I skipped to 2-2; steps 5 and 6. (I called that the "3rd adjustment").

I shouldn't have done that...messed with the Bias Current Adjust after I cranked on kVR2 .
 
Here's my right channel F-4619 board. Service manual says the ground pin is furthest away from Sankens.

DSC00445.JPG

SansuiJavier confirms the manual is correct...the ground pin is furthest away.

So I don't know what I did wrong.

Someone has offered to send me a couple of used Sankens to try. I'm going ahead and order the Bourns and some caps.
 
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