Calrec PQ1549 rev.4 from the Gyraf

[mariaaudiodesign]

Hello Guys
For some time I have a problem with the 1549 EQ.
When you start it turned out that only work Low-Mid and Hi-Mid Sections.
The high does not work ... potentiometers rotate as nothing changes.
and the lower section shall be instituted and began working as a generator.
Maybe there is a problem with feedback somewhere, but I can not find it.
for the record. I complied with all the polarities of the scheme and I measured voltages. examined several times for installation errors. IC sockets are not covered directly soldered to the board.

Sorry for Bad English...
Thank you for Help...

 

[gyraf]

Please use the dedicated help thread - that way any solution can be re-used later by someone with related problems:

calrec PQ1549 help thread: http://www.groupdiy.com/index.php?topic=5957.0

Similar problems has been seen before, I think - often in higher frequency bands

Jakob E.