Beginner's help - How to diagnose/fix a Synergy module

[lespauled]

I have watch videos like this one, that show you how to diagnose a problem with a guitar pedal.



It basically works by shortening the path to the output until you find the component causing the issue.

I have an old Synergy BB/BE module that seems to have died. I tried new tubes, with no luck. I was wondering how I would go about trying to diagnose the problem myself. I have nothing to lose, since it's not working now.

Anyone have any ideas for someone starting out?

Thanks!!!

 

[stev3wood]

@lespauled a huge safety warning, man!
That audio probe technique from the video is awesome for low voltage pedals, but a Synergy module is a tube preamp, and those things have lethal voltages inside, we're talking 300-400V+ for the plates! The video mentions needing a cap rated for at least 400V if you use the probe on an amp.
Seriously, if you are a beginner, look up how to safely discharge the filter caps first. it's cool that you have nothing to lose, but your life is worth more than the module!

before probing, get a multimeter and check for B+ voltage on the tube plates. If there’s no high voltage, the problem is in the power supply section of the module, not the signal path.

 

[voltagepathmaker]

Also make sure to check the heater voltage at the tube pins. If you don’t see any filament glow, the problem might be with the low-voltage rail or possibly a broken trace. It’s also a good idea to inspect the solder joints and ensure the ribbon cable is in good shape, as Synergy modules can experience connector fatigue.

 

[Circuitsmith]

Make sure to check the continuity from the power supply to the plate resistors, if the resistors are open or there are faulty traces, it can disrupt the B+ even if the power supply itself is working fine. And remember, when you're working on live tube circuits, it's safer to use just one hand to lessen the risk of a shock.