New Crack build, high voltage on T5 and T9

[[email protected]]

Greetings! First time build here. Everything has gone fine so far in terms of testing required in the manual, but I can't resolve a curious problem.
About 90 seconds after powering on, the LED attached to A3 will start to blink, then increase in brightness while voltage at T5 and T9 rise to about 140V and stay there. All other measurements are within spec until the LED blinks and T5 and T9 spike.
I've done all the obvious/routinely suggested trouble shooting, so I'm at a dead end. Can anyone help me out?
I have a three minute video of what happens which I'll try to attach or can send to those interested.

[Paul Birkeland]

Can you unplug the 6080 and recheck this behavior?  How about posting some build photos?

[[email protected]]

Not sure if my photos went through. Maybe there's a MB limit? Lemme know if they don't show.
Removing the 6080 stopped the voltage spike to T5.

[Paul Birkeland]

I would definitely be interested in seeing the build photos.  You may need to reduce them in size slightly if they aren't posting.

[[email protected]]

Ok. I'll try one at a time.

[[email protected]]

photo 9 pin

[Paul Birkeland]

What voltage do you get at A3?  If the LED is blinking or off it will either be 12V or 0V usually.

[[email protected]]

With the 6080 removed, A3 is 1.573V, which from what I understand, is in spec.
With 6080 removed, it stops blinking. T5 stays steady at 94V.

[[email protected]]

photo transformer

[Paul Birkeland]

I would suggest resoldering all of the connections in the amp.  You can leave the ones alone where the LEDs are, as those look pretty solid.  Everything else needs more heat and more solder.

On the UF4007 diode bridge, that one that you have going up and over the black wire may cause some problems down the road and I would recommend going back to the manual and reviewing the installation instructions for that part.  It should not go over the black wire and the way it is installed allows for the possibility that the leads of it and the diode next to it can touch and short out the high voltage power supply.

[[email protected]]

OK. I'll give it a shot.

[[email protected]]

I basically re-soldered the entire amp, and moved the diode, yet the problem still persists. Could it be a tube?
Short of dismantling it and rebuilding it, what are some options?
Updated pics enclosed.

[Paul Birkeland]

Can you wrap the wires on the octal socket?  A loose connection on the octal socket could cause issues like that up at terminal 5.  This is very unlikely to be a bad tube.

[[email protected]]

My apologies, but I'm not entirely sure what you mean by 'wrap the wires'. B4 is very loose, though.

[[email protected]]

The voltage at T5 and T9 are identical @136.5V, if that offers any clues.