Seeking help with Speedball

[ike]

Hi everyone,

I have built the Crack and up and running for the past few months without any problems.  I just finished installing the speedball upgrade and my voltage check were way down from specs.  A couple of the LEDs on the large PC board are not lid. 

Here are the voltage #s
1: 3
2: 40
3: 0
4: 40
5: 36
6: 0
7: 0
8: 0
9: 35
10: 0
11: 0
12: 0
13: 40
14: 0
15: 118
20: 0
21: 190

Thank you in advance
ike

 

[Paul Birkeland]

Do you have two small PC boards up front or one small PC board up front?

These voltages tend to suggest that the TIP50 transistor heatsink mounting kits were not properly installed.

-PB

 

[ike]

Hi PB,

Both small PC boards are upfront.

 

[Paul Birkeland]

Remove the 6080, then test the voltages at terminals 1-5 with just the 12AU7 installed.

-PB

 

[ike]

Terminals 1-5, all zeros.  The LEDs on the two small board and on the tube sockets are all lid up

 

[Paul Birkeland]

Do you have any voltage above 0V in the amplifier with just the 12AU7 installed?

 

[ike]

All 0V across terminals
Thanks

 

[Paul Birkeland]

If you have 0V across terminals 1-5 and you have LED's glowing on the 9 pin socket, you are not measuring your voltages properly.  Are you sure the meter is set to DC volts and not AC?  Are the probes connected properly? 

 

[ike]

Okay, here are the initial measurements:
1: 75
2: 233
3: 0
4: 233
5: 71

I went back just to double check and i got zeros across 1-5 terminals.  Is that strange?

 

[ike]

I just figured out why the second measurements were all zeros.  The wire on my cheapo multimeter were loose and not connected the probe.

 

[Paul Birkeland]

Is there any update on your voltage measurements?

 

[ike]

yes,
Here it is again:

Terminals
1: 75
2: 233
3: 0
4: 233
5: 71

Thank you

 

[Paul Birkeland]

Alright, that confirms no issues up front.

With your meter now working properly, if you find that the voltage available at terminal 2 drops very low when you install the 6080 and run the amp for a brief period, then you need to look at the mounting hardware of the TIP50 transistors and how they are to be installed in the manual.

-PB