Troubleshooting completed kit

[Paul Birkeland]

You can do this test with the 2A3's in or out of the sockets (or try both), but the 12AT7 does need to be plugged in.

[Wrekless]

I got roughly 425 on each, looks like a resistor fried also.  That would have been the explosion, spark, smoke.  Right when I measured IA.

[Wrekless]

12AT7 only...

[Paul Birkeland]

You can e-mail replacementparts(at)bottlehead(dot)com for four new LED's, two 2N2907's, and two MJE5731A's.

For now, remove the red wires from HV+ that feed this board, and that will take the driver out of the circuit.

With those wires removed, put one of the black wires you previously disconnected back into the HV+ pad, and run the amp with a 2A3 plugged in on that side. 

If your fuse holds up, try connecting the other black wire and running the amp with both 2A3's.

-PB

[Wrekless]

Did all that, 2A3's aren't glowing, 12AT7 is.

[Paul Birkeland]

The 2A3 glow isn't all that easy to see, but the point of the test is to see that the fuse isn't blowing.

Now, try running both the black plate choke wires back in the HV+ pads.

[Wrekless]

Ran both black wires back into HV+, fuse is good.

[Paul Birkeland]

Alright, this is a little mysterious, but at this point you'll want to replace the blown transistors on the C4S board, then test the entire amp completed.