Bassman AB165 burned filament resistors

[fredcapo]

Working on a seemingly all original Bassman AB165 head. Bloated, dripping ps electrolytics causing fuse to blow after on/on a few seconds.

There are two resistors tied between ground and the filament rails off the pilot light. Both are fully open/burned/broken. Is this typical? What are the values (don't see on schematic). Thanks.

[olddawg]

That's the virtual center tap. Usually 100 ohms I think. Check to see if it is an original PT. Sometimes replacements have a center tap for the filaments. You can't do it both ways at the same time.

[Leo_Gnardo]

Working on a seemingly all original Bassman AB165 head. Bloated, dripping ps electrolytics causing fuse to blow after on/on a few seconds.

To save a little cash in the future, if you see dodgy looking filter caps there's no need to "prove" they're bad by burning fuses. Also why take a chance on wrecking the PT?

On amps this age I automatically replace the bias filter cap without hesitation. Cheap insurance.

Burnt filament balancing resistors mean there's been a short in an output tube. Or possibly an output tube missing its locator key inserted incorrectly. Kaboomski!

[Steve Conner]

Yup, bloated dripping electrolytics go in the trash immediately. If the amp has a tube rectifier, you're more likely to wreck that than the PT, but it's still undesirable.

Russian tubes go kaboomski, Chinese ones go Sum Ting Wong.