Fender DRRI no bias

[rockman627]

Original problem: amp had a lot of hum when you turned up the reverb, and a bit too much with the reverb off. It had new filter caps so I started checking ground connections, using Rob Robinette's method of using a probe with one end clipped to the chassis and touching the other end to the ground side of an applicable component. Unfortunately, when I checked R37, I accidentally touched R38 and it sparked. I think that shorted out the C-, because the hum got even louder. Then I saw both output tubes were red plating. Now instead of getting -49vdc at TP5 I get .168vdc. Between CR1 and R69 I get -16vdc and at CP10 I get 35vac. I'm thinking the power transformer is not supplying proper bias but before I order a new transformer I want to check with you guys. Am I on the right track or do I need to do more checking?
Fender-65-Deluxe-Reverb-Schematic.pdf

[Delta362]

I wouldn't be quick to suspect the power transformer. I would start by pulling the output tubes and then measuring voltages for the power supply and each node, including the preamp nodes. See what voltages look way off compared to the schematic. That will help narrow down the issue. You may have just blown a resistor.

[Helmholtz]

No reason to suspect the PT. Bias winding voltage (35VAC) is good.
Rather measure R69 with one end lifted and test CR1.

If using a grounding probe always safely clip to the circuit point to be grounded first and then ground the other end of the probe.
Never ground a point carrying a DCV (check first).

[rockman627]

I bitched and moaned about lifting one side of R69 because I hate lifting these pcb's, but it wasn't too bad at all. Hmm, it measured open at all settings. CR1 measured .667 one way and open the other. Time to order flameproof resistors.

[Helmholtz]

So CR1 is good.

[rockman627]

Should be. It's weird, R69 measured 22ohms in circuit so I figured it was good. I'm glad I listened to you. Thanks.

[rockman627]

I replaced the resistor and amp is good. The original problem of reverb him also cleared up. Once again, my thanks.

[Helmholtz]

Thanks for reporting back.
It's a shame that many OPs don't, even though our free advice saved them time and cost.
I think it's only fair to get a final feedback when I sacrificed my time to help.

[rockman627]

Yeah I have seen a few posts where I didn't find out what the solution was. Take another 5 minutes please.

[rockman627]

I owe this forum a donation. If I can stop getting unexpected costs, I would. I have to spend my tax refund plus more getting a tree removed before it falls into my house.