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A customer drives in from an hour away with a '68 Princeton reverb reissue - no reverb. 6 months old and under warranty, but he had already tried a new reverb pan, and a new 12AT7 drive tube. In out of town cases, I like to open it right up and see if I can save the customer a second trip - fix it on the spot then.
Crashed the springs, they were loud, so the drive was the problem. Open it up. Tube conducting, several volts on cathodes, B+ on plates. Signal on grid, none on plate, just ripple. Starting to suspect the reverb transformer. I don;t like suspecting transformers, they are usually innocent.
I was about ready to call it the transformer, and end the pleasant visit we were having, and then...
MY eagle eyes spotted the four push-on posts for the transformer wires and there before me the red and blue primary wires were shorted together. the red one was bent over to touch the one next to it. So B+ went on to the plate, but no transformer action. A quick bend with my pliers, et voila. Reverb.
Button it up, customer very happy, he even gave me a nice tip.
And the transformer was innocent again.
Crashed the springs, they were loud, so the drive was the problem. Open it up. Tube conducting, several volts on cathodes, B+ on plates. Signal on grid, none on plate, just ripple. Starting to suspect the reverb transformer. I don;t like suspecting transformers, they are usually innocent.
I was about ready to call it the transformer, and end the pleasant visit we were having, and then...
MY eagle eyes spotted the four push-on posts for the transformer wires and there before me the red and blue primary wires were shorted together. the red one was bent over to touch the one next to it. So B+ went on to the plate, but no transformer action. A quick bend with my pliers, et voila. Reverb.
Button it up, customer very happy, he even gave me a nice tip.
And the transformer was innocent again.
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