Film-Tech Forum ARCHIVE: QSC ISA450 high failures in muting circuit

This is topic QSC ISA450 high failures in muting circuit in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=011585

Posted by Eric Robinson (Member # 2966) on 01-02-2014, 10:03 AM:

We have a theatre which uses a large number of QSC ISA450 amps. We have sent these amps in for repairs to QSC numerous times due to a failure in the muting circuit. The repair notes from QSC note that the muting section has failed and that they replace the C7 capacitor to repair it. According to the manual for this amp, the purpose of the muting section is to avoid damage to the amp during clipping or shorting of the output.

Does anyone else here have the same problem?

Posted by Mark Gulbrandsen (Member # 72) on 01-02-2014, 12:10 PM:

The only QSC failures I have are old USA series amps that stop working after 20+ years of service and also once na while the level pots on the DCM amps. The level pots just become dirty and channels drop out. I prefer to replace them because they are elcheapo conductive plastic pots and cleaners might worsen the problem over time by breaking down the plastic.

As far as your problem goes I have gobs of ISA amps in and never have any issues with them.

Mark