Need Help Troubleshooting, Shorted Terminals 3 and 4

gordonhall · 2151

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Offline gordonhall

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on: August 29, 2011, 04:08:04 AM
I built the crack + speedball and was getting voltages far too low on terminals 1 and 2 (about 40 volts each). When testing terminal 3 I caused a spark (fairly sure it was shorting terminals 3 and 4) and now none of the led's light up. The tubes still glow a bit, though, which is odd.

No, I did not get the crack working before attempting the speedball. I accidentally ripped one of the leads of the 3k ohm resistors, so figured I'd just push on (regretting that decision now)

The 270 k ohm 1 W resistor seems to be fried, its giving me resistance readings well into the megaohms.

Any assistance would be very much appreciated, and perhaps a list of components I should replace (LEDs, 270 k ohm 1 W resistor and the 3 k ohm resistors for starters)



Offline Doc B.

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Reply #1 on: August 29, 2011, 06:52:25 AM
There seems to be two different problems, the initial low voltage and now the dead LEDs. Probably best to start by taking voltages at the terminals listed in the manual and posting the ones that are off from the manual. If only the 270K bleeder resistor was open the power supply should still supply voltage to the amp circuit, so there may be other damage.

Dan "Doc B." Schmalle
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Bottlehead Corp.


Offline gordonhall

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Reply #2 on: October 10, 2011, 11:32:26 AM
For anyone who does in fact short terminals 3 and 4, replace all of the LEDs. That got it up and running.

Other fixes to my problem included, not soldering one of the resistors and confusing the speedball transistors