230v Crack with Speedball - High Readings (Resolved)

[Jimb0]

230v Crack with Speedball tested on my step up converter

Getting some high readings here:

Big Board
OA - 168v
OB - 121v

Small Board
OA - 121v
OB - 168v

Pics
https://imgur.com/a/4G28eta

 

[Jimb0]

Resistance checks

3) 3.4ohms
6) 2.5 ohms
7) 2.35k ohms, continues to rise
B3) 2.6k ohms, continues to rise
B6) *

RCA Jacks Center Pins
The red and black jacks are reading ohms not k ohms like in the manual
Black 93ohms
Red 95ohms

Big Board Resistances
OA - *
OB - *

 

[Paul Birkeland]

The big board won't work if the small board isn't working first.  I would pull the 6080 and just run the amp with the 12AU7, then focus your debugging efforts there.

Does the 12AU7 glow? 

Do the LEDs on the 9 pin socket glow?

I suspect the answer to one or both of these questions is no.

 

[Jimb0]

Hey PB. I rechecked it without the 6080 and both the 12AU7 tube and the 2 LED's on the 9 pin socket were glowing

 

[Paul Birkeland]

Can you check the voltages with just the small tube installed?

 

[Jimb0]

Small Board
OA - 85v
IA - 232v
G - 0v
IB - 232v
OB - 139v

 

[Paul Birkeland]

OK, it looks like you have some debugging to do on the front half of the amp.  139V is definitely an issue.

I would follow the flow chart on page 20.  If that isn't helpful, knowing the DC voltage at A8 could be helpful.

 

[Jimb0]

Hey PB. It turned out I was using a 12AX7 when I last tested it. I had purchased a lot of 12AU7's on eBay and the seller wasn't aware of the 12AX7's in the lot. The amp was actually working fine the first time around. I assumed all the tubes that I was testing were 12AU7's so I thought for sure a part failed. Sorry for wasting some of your time. Always appreciate the help you provide. Have a good weekend PB!