Small PJCCS problem

SilverS · 1894

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Offline SilverS

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on: January 21, 2012, 11:17:12 AM
I got everything wired up properly, and hooked up my Quickie only to find the right channel was only half working (it sounded very quite and there was no low end response). After that I  looked at the board and found one of the transistors had solder joined between two pins, after fixing that, the right channel completely cut out.

Just to make sure, on the board side B is the right channel, and side A is the left?

Oh and the left channel sounds perfect, nothing wrong there.


Offline Paul Joppa

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Reply #1 on: January 21, 2012, 03:38:16 PM
To be absolutely sure, notice that the PC board terminals "OA" are the output of the "A" side. They go to the tube and an output capacitor, which goes to the output jack. Easy to trace!

Paul Joppa

Offline SilverS

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Reply #2 on: January 21, 2012, 05:07:08 PM
Interesting read outs when I tested voltages...

IA and IB both read normal at 37V

A6: 1.8V     (Normal is 19-21V)
B6: 243.2V  (Normal is 19-21V)

A5: 15.13V (Normal is 2V~)
B5: -1.45V (Normal is 2V~)


Offline Paul Joppa

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Reply #3 on: January 26, 2012, 05:29:23 AM
Sorry for the late response - the forum software sometimes fails to alert me to new posts.

For A5 and A6, I speculate that you have accidentally reversed them, which is true shows them to be approximately correct. Have you corrected the filament battery orientation (see the sticky)?

For the B tube, it appears that no current is flowing from the PJCCS board to pins 2-4-6. Usually this indicates a bad solder connection. Note that the middle leg of the transistor is harder to solder to than the others because it is connected to the heat-dissipating surface, so that would be a likely spot for the solder joint to fail.


Paul Joppa

Offline SilverS

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Reply #4 on: January 31, 2012, 02:23:49 PM
I resoldered every connection on the B side, and checked to make sure my red wires were going to the right pins and everything checks out. I'm not quite sure what the problem could be, no connections are shorting and everything on the B side looks exactly like the functioning A side.


Offline Paul Joppa

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Reply #5 on: January 31, 2012, 04:05:54 PM
Could be a bad socket connection or a dirty tube pin.

Incidentally, your 243v measurement must be mV, not V! Check the tube voltages again, after removing and re-inserting the tube a couple times (this often cleans the pins enough to work). These tubes have not been made for decades, so all of them have at least a little corrosion on the pins!

Also swap the tubes just to be sure it's not a bad tube...  :^)

Paul Joppa

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