Phase Linear replacement parts?

[speakrsrfun]

I have a Phase Linear 3500 II series pre-amp and it's finally gone silent on the right channel. I know it's the balance pot and I'd like to replace it but I can't find an exact replacement for the unit that's in the pre-amp. Does anyone have any suggestions? If need be I'd be willing to replace the whole volume/balance module out with a working salvaged unit. Hell I'd buy a module with a dead volume pot just to get the balance pot.

Anyone?

 

[mbz]

Do you ever use the balance pot? Never use mine.
As a short term fix consider replacing the balance pot with 2 nice spec resistors

 

[speakrsrfun]

that may not be a bad idea for a quick "While I await a replacement" fix. I'm assuming since the dual stack pot is dual 100K pots I would just use a 100K resistor across the appropriate leads?

 

[mbz]

Couldn't locate the service manual. The wiper (audio out) is normally at the mid point.
So if you have a 100k pot you would normally use 2 50k resistors. Please don't bank on this,
check the schematic. Sure you get the drift...

 

[speakrsrfun]

It'd dual stacked 100K pots, so think two 100K pots in line, one used for the left one for the right. So in this case full resistance would be 100K, no?

 

[mbz]

It'd dual stacked 100K pots, so think two 100K pots in line, one used for the left one for the right. So in this case full resistance would be 100K, no?

Yes, I stand corrected, only 2 100k's required


Couldn't find the schematic, below is an extract from Yamaha CA-1000

 

[PRR]

You don't even need 100k resistors. One end of each side (opposite sides) of each gang goes to ground. Take the other two wires on that gand and nail them together. Do the same on the other gang. Done.

 

[speakrsrfun]

It wasn't the balance at all. I un-soldered the volume pot, disassembled as best as possible, reassembled, re-soldered and put it back in, same issue. Then I started moving things around to notice that in certain positions with the board suspended it worked. Touched the ribbon cable, crackle and right channel dead. Taking every female receptacle and giving the contacts some love. Wish me luck.

 

[speakrsrfun]

I take that back, certainly the volume pots.

It wasn't the balance at all. I un-soldered the volume pot, disassembled as best as possible, reassembled, re-soldered and put it back in, same issue. Then I started moving things around to notice that in certain positions with the board suspended it worked. Touched the ribbon cable, crackle and right channel dead. Taking every female receptacle and giving the contacts some love. Wish me luck.

 

[speakrsrfun]

You don't even need 100k resistors. One end of each side (opposite sides) of each gang goes to ground. Take the other two wires on that gand and nail them together. Do the same on the other gang. Done.

OK so I've got this straight, being there's 6 pins, 3 for each pot in the line, center pin being live the two outsides being ground. if I jumper the outside two pins on each pot it should eliminate the resistance and allow full signal correct?

 

[speakrsrfun]

Can anyone assist me in maybe helping determine which pins to jump to delete the balance but keep the pot in the board. It doesn't seem to be as easy as it should be, maybe there's other aspects like the loudness, mute etc that play here also. I don't know I'm talking out of my ***. Here's a pic of the board, volumes right, balance left six pin arrangement.

An externally hosted image should be here but it was not working when we last tested it.

 

[Mike Gergen]

Try here.

Absolute Sound Laboratories

Mark used to have a large spare parts warehouse for lots of 1970s gear.

 

[mbz]

3pins for each channel, input, output(wiper) and ground. As already pointed out, in the
centered position, the input and output are connecetd together, so no need for resistors etc..


Use shorting links/off cuts as per below.