High Voltage readings after Speedball addition

[mvr_in_london]

Hi

I decided to add the Speedball to a perfectly working, nice sounding, Crack

The Crack resistance readings / voltages were spot on (+/-  10%) before the speedball.

After the speedball addition I'm getting the following -

Terminal - Voltage

1 - 178
5 - 178
7 - 178
9 - 170
13 - 178
15 - 200

A1 - 180
A3 - 15
B1 - 180
B3 - 175
B4 - 175
B6 - 176

The rest are fine

If it matters - I am in a 220v country - but I guess not as the transformer takes care of that and the voltages were fine before the Speedball

Help would be much appreciated

Thanks

Mehul

Edit:  Just saw the sticky about corrections to the manual re: Terminals 19-21

[mvr_in_london]

Tried swapping tubes, same numbers.

Some help with this would be much appreciated

[Doc B.]

It sounds like the problem might be on the bigger PC board under the 6080 socket. Double check the wiring that connects that PC board to the rest of the circuit, and also check that the smaller metal can transistors are 2N222As on the big board and 2N2907s on the smaller PC boards by the 12AU7 socket.

[mvr_in_london]

Thanks Doc

I checked the capacitors.  They are correctly installed.

I double checked the wiring and resoldered all 8 points

Same problem.

Is there something I can check to help narrow down where the problem might be?

[Doc B.]

OK A6 and A8 or OK, and all tube plates have some kind of voltage on them which seems to indicate that the B+ voltage is getting everywhere and that one side of the 12AU7 is functioning properly.  It looks like the other half of the 12AU7 is being pulled too high. Is the 237 ohm resistor on that PC board (R1) in fact the correct value?

It also appears that neither half of the 6080 is conducting properly. Are any of the LEDs lighting up? If not, there might be some ground connection that was missed. I would suggest checking the connection of the black wire jumper that goes across the middle of the PC board that is under the 6080 (page 16), and double checking all of the connections shown on page 25. Also check that the 31.6 ohm R1 resistors on that PC board are the correct value.

[mvr_in_london]

Thanks very much Doc.

Fixed it.

Turns out the jumper from terminal 3 to the center of the 12au7 socket was making an intermittent connection at the socket end. 

When I checked the voltages it must have been disconnected, but when I checked if the led's at the socket were lit (they were) it must have been making contact.  Obviously, I did not notice that the led's were off when I checked the voltages.

I must say that the Speedball has improved the sound greatly and I am very happy with the amp.

Thanks

Mehul

[MxT]

I also had weird reading after the speedbal upgrade my terminal 5 reading was totally out of spec- turns out it was a tube- after the tube roll readings were spot on