Soundcraft 8000, Aux master problem

[Mitchy_M]

Hello!

I need some assistance with the following issue.

I recently purchased a Soundcraft 8000 (32x8x2) and recapped several channels. Everything is working fine except for some aux masters. So, I recently attempted to fix the issue. The output was crackling, and there was very little output. I tried swapping the op-amps, and I discovered that one of the two op-amps associated with Aux1 was very hot. Despite trying to replace it with another op-amp, none of the aux channels are working anymore.

The headphone output is functioning, and I can listen to all channels, but I cannot use the AFL for the aux channels. The LEDs are working, so it doesn't seem to be a power issue. Does anyone have an idea where I should start looking to identify and fix this problem?

In AUX 5, I only get output from a scratchy potentiometer when I turn it. Unfortunately, I no longer have output from any of the aux channels.

I'm also curious about the purpose of the small potentiometer on the PCB. I have attached a link with the schematic is at page 15.

Thank you in advance!

https://www.soundcraft.com/zh/produc...t-diagrams-pdf

 

[jensenmann]

The trimmers are used to trim symmetry of the output signal.

Check if the supply voltages are ok on that particular channel. It´s quite likely that the meters get their supply voltages not from tha audio rails but from somewhere else (sorry, too lazy to wade through all those schematics, it´s time to go to bed over here)

 

[drtechno]

Hello!

I need some assistance with the following issue.

I recently purchased a Soundcraft 8000 (32x8x2) and recapped several channels. Everything is working fine except for some aux masters. So, I recently attempted to fix the issue. The output was crackling, and there was very little output. I tried swapping the op-amps, and I discovered that one of the two op-amps associated with Aux1 was very hot. Despite trying to replace it with another op-amp, none of the aux channels are working anymore.

The headphone output is functioning, and I can listen to all channels, but I cannot use the AFL for the aux channels. The LEDs are working, so it doesn't seem to be a power issue. Does anyone have an idea where I should start looking to identify and fix this problem?

In AUX 5, I only get output from a scratchy potentiometer when I turn it. Unfortunately, I no longer have output from any of the aux channels.

I'm also curious about the purpose of the small potentiometer on the PCB. I have attached a link with the schematic is at page 15.

Thank you in advance!

https://www.soundcraft.com/zh/produc...t-diagrams-pdf

Its been a while, but the first thing you should do is measure analog ground to power supply ground which is 10 ohms. I had a few come in after someone buys one and the grounds are screwed up. Usually when you have a dead buss its because of the ribbon cable. Op amps nuking at the output is more of a messed up ground because Chassis ground is suppose to float in this design.

 

[Mitchy_M]

Thank you!
I will try these suggestions out today!