Sparks?!

eddhartwellmusic · 2233

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Offline eddhartwellmusic

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on: May 05, 2016, 06:21:37 AM
So I've made my Mainline, the resistance check went perfectly, but when I went to check the voltages and put the positive lead on +275vDC it sparked! A bit scared to try again, any thoughts why this might be?!



Offline eddhartwellmusic

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Reply #1 on: May 05, 2016, 06:23:56 AM
Also, is there a chance this may have blown something else in the circuit?



Offline Doc B.

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Reply #2 on: May 05, 2016, 06:30:09 AM
You shorted two terminals together that were at different potentials. You're going to need to proceed with the voltage checks to determine any answers to your questions. If you don't have a steady hand cover all but the very tip of the red probe with insulated tape.

Dan "Doc B." Schmalle
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Offline fullheadofnothing

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Reply #3 on: May 05, 2016, 06:37:15 AM
Usually sparks are caused by shorting two terminals together with the probe itself. In other words, it is not a problem with the build.

Were your voltages correct on the power supply board testing earlier in the manual?

If so, you still need to do your final voltage checks. Proceed with caution, and never take your eyes off what you are doing. If you cannot safely use a probe, you can attach clip lead, power up, take one measurement, power down, wait, then move the lead, power up, measure, power down, and so on.

Joshua Harris

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Offline eddhartwellmusic

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Reply #4 on: May 05, 2016, 07:00:49 AM
OK great, thanks for your help, I will carry on with the test. Up until this point all test have been spot on.

Just a thought, could it be that I somehow soldered two points together? I've been very careful not to, and can't see where I have, but may have missed it Just a thought...



Offline eddhartwellmusic

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Reply #5 on: May 05, 2016, 07:43:23 AM
I just re-tested, it seems I must have been touching two points somewhere. All good this time around.
Readings are as follows:

+275vDC Power Supply Board = 269
+6.3vDC Power Supply Board - 6.27
IA A side C4S = 269
IA B side C4S = 269
Breg = 221 and 219
-reg (both sides) = 0
Kreg (both sides) = 12

I'm assuming these results are close enough? They are at least consistent. Maybe not precise due to my cheap tester?



Offline Doc B.

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Reply #6 on: May 05, 2016, 08:54:45 AM
If that values are within the tolerances specified in the manual you are good to go.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.