PV XR400b mixer/amp with 200 H power module low output

[Down with SMT!]

latest development

Enzo,
JFTR
[This unit, although had been in a smokey environment, I don't believe has seen a lot of use over the years- faders seem a little stiff, almost like new- of course non-use is probably the reason....
the interior is very clean (no fan of course) but no apparent trace of heating at all on the amp section pcb that is visible w/o removal.]

Got back to this unit after the wkend.
Had pulled the mixer pcb & tested it out of the chassis-
Well NOW I have reasonable monitor output!
I've flexed the board a bit, gently wiggled pots & jacks & searched for any corrosion, questionable solder joints, etc. seems clean- visually anyway-
then I went on to spray the rotary pots- as the vol. channels were a little noisy.
Could the op amp be intermitt, itself?
Any thoughts?
thanks, john

[Enzo]

I sincerely doubt the op amps are intermittnt. Far more likely the sockets they live in are intermittant. Often as not, just pulling an IC halfway out and shoving it back in refreshes the contact surfaces,

[Miss Anthrope]

Look at the ppower amp board. On the end farthest from the power transformer wires, there is a four-wire connector for the cable to the front panel. Pull it off. Connect amp to speaker and power up. The four exposed male pins will be in that corner. The pin nearest the corner should be the amp input. Touch it with your finger. Hear hum? You can apply a test signal there with clip wires.

If that is strong, then the power amp is probably OK, if it iis weak, then we fix the power amp next. If the PA is OK, then we look to the whole graphic section up front. ANything between the GRAPHIN in jack and that four-wire cable.

I tried this with my PV and got a nice loud hum. Does that mean that the PA is not broken and the problem with my unit lies elsewhere? I started a thread, but so far no ideas. Thanks to anyone who's willing to give me a shout.

[Enzo]

That is exactly what it means.