Dead Mackie HR624 MKII measurements... check my work?

I have a dead Mackie HR624 MKII part of a pair I got for free. The other one powers on, but emits only static.

I want to use this as a learning opportunity to do test measurements and diagnosis and hopefully fix the problem.

Schematic: https://www.audioservicemanuals.com/m/ma...

I am starting with the dead monitor first. Like I said, dead, no power light, no sound. Fuses checked and are good. A visual inspection does not reveal anything obvious. no leaking, bulging capacitors. no shorts or burnt parts of the board. the grounding wires look ok at the connection point, no corrosion, but maybe they could be cleaned up anyway.

I did a Transformer AC Output Test and got ~31V AC from the center wire to each outer wire and ~64V AC between the two outer wires, so it seems power is being correctly delivered to the main circuit board.

Next I did a Main DC Power Rail Test and measured 0V DC on both test points.

So that led me to the bridge rectifier. I got the correct forward voltage drop (~0.6V) and an open circuit reading in reverse.

So I did some point-to-point continuity tests

• AC Path (Transformer to Rectifier): PASSED. There was a good connection.
• Ground Path (Center Tap to GND): PASSED. There was a good connection.
• Positive DC Path (Rectifier + to Capacitor C39): FAILED. Showed "1" (no connection).
• Negative DC Path (Rectifier - to Capacitor C48): FAILED. Showed "1" (no connection).

I'm guessing there is a physical break in the copper traces on the PCB? If so, reflowing that is beyond my knowledge and skill probably. But I could do small jumpers?

Or am I misunderstanding the result of the measurements?

I can share pictures if anyone can help me see the issue the measurements are pointing towards. But now i feel a little over my head.

Thanks.