Fender Blues Junior Cream board no output

[Steelwitch]

Hey folks,

I have a blues junior that’s kinda giving me a hard time at the moment. There is some hiss from the speaker but other than that, no output of any kind. What i do know is that the input Jack is good, output transformer appears to be ok (no continuity between primary and secondary) and there is no affected change by swapping out tubes. Looking for suggestions on what I should troubleshoot next.. there is no visual indication of anything overheating or being damaged, I’m probably glazed over something really obvious.. thanks!

[52 Bill]

If there is hiss coming from the speaker, you can probably rule out an output transformer or power tube problem. Have you checked the tubes?

Visually check all of the solder joints on the tube board, especially at the tube sockets. Then carefully start to take voltage readings starting from the power tubes, working back to the preamp.

As your meter touches different points in the power supply, you should hear pops and clicks from the speaker. See if the B+ is there from the OT to the driver, to the tone stack, to the preamp, etc.

[mozz]

Check for continuity on the primary leads to each other and on the secondary leads to each other, not just for shorts between both sides.

[Steelwitch]

Right after posting this i found the culprit. One of the joints from the ribbon connector was completely broken off. False alarm I guess, but thanks for your suggestions

[eschertron]

Troubleshooting is troubleshooting. There is voltage (B+) available or not. There is signal available or not. Once the problem is isolated, knowledge of specific components - like ribbon cables, for instance - is required to make a fault determination, but getting there follows the same basic procedure.