Speedball LED issue... any ideas? [resolved]

[moreps]

Hey guys,

I recently built a Crack and had it working well, figured I might as well finish the Speedball upgrade since I had the parts. When I finished Speedball and went to test it, I noticed that not all the LEDs were turning on. None of the voltages were correct (1 was at close to 0V and 5 was at 45V). The LEDs connected to A3 and A8 light up, as well as the LEDs on the small boards A and B. Only one of the pairs of LEDs on the bigger speedball board lit up. Then, the LED connected to A8 dimmed and went out.

This is pretty bizzare, so I made sure it was the speedball board by turning it 180 degrees and reconnecting all the wiring. Sure enough, the same set of LEDs on the board never lit up, and this time the A3 LED dimmed and went out.

So far, I have done the following to try and troubleshoot:

• Check the resistance of each resistor using a multimeter.
• Resolder every joint.
• Swap the 2N2222 transistors on the board.
• Replace the LEDs with the extras that came with speedball.

I tried to swap the TIP-50 transistors but I don't think that's happening because the heat sinks dissipate most of the heat before I can remove it from the board.

Does anyone more knowledgeable have any ideas of what else I should try to fix it? I'm kind of at a loss right now.

[Paul Birkeland]

Does anyone more knowledgeable have any ideas of what else I should try to fix it? I'm kind of at a loss right now.

Yes, stop swapping parts.

Post a full list of your voltages.  Also put the complete Speedball kit in.  I'm not sure where you got extra LED's, but if you took some from elsewhere in the circuit, you will need to replace them in order to get an accurate set of voltage readings.

If you rotated the big Speedball PC board and that influenced the LED on A3, you ought to carefully go over the manual and check your work.

-PB

[moreps]

Thanks for the quick response. My Speedball kit came with 12 LEDs so I just used the extras. With everything from speedball in the crack, I got the following voltages:

Terminal 1: 0
Terminal 2: 55
Terminal 3: 0
Terminal 4: 53
Terminal 5: 46
Terminal 6: 0
Terminal 7: 0.6
Terminal 8: 0
Terminal 9: 44
Terminal 10: 0
Terminal 11: 0
Terminal 12: 0

At which point, I realized I was smelling smoke so I turned it off...

The two LEDs closest to the capacitors were the ones that didn't light up, as well as A8 LED turning off after a second.

I feel like I've triple-checked all my wiring by now, especially on the big speedball board, which is why I just feel at a loss right now.

[Paul Birkeland]

It is very likely that the insulating hardware on your TIP50 transistors is not correctly installed.  Please check it against the manual.  If you're not sure, pull the 6080 and run the Crack with just the 12AU7, then check voltages at terminals 1-5.  (If you do this, and you see 55V or so at T2 and T3, don't leave it on for too long; the issue is elsewhere)

Having only 50V or so on your high voltage supply indicates that your Crack circuit is drawing excessive current, which will get things very hot.

-PB

[moreps]

Wow, thank you so much! It ended up that I switched around a lock washer and fibre washer. I can't believe I made that mistake, and I don't know if I ever would have found it without your help. I never considered it as something that would even have an affect besides physically holding it in place.

I really appreciate your help, man.