Speedball Resistance Check

slackbits · 1766

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Offline slackbits

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on: May 21, 2017, 05:28:22 PM
Hi all,
I am doing the resistance check on OB and OA on the big board.  I touched OB and my multimeter started going up it to MΩ then it just went to 0.  Same with OA.  Then both would not budge at all only giving 0. (Like I was touching my shirt or something.)  Testing the 150KΩ and 47KΩ resistors show just that, well 46.5kΩ for the 47KΩ.  The multimeter is an Ideal 61-340 if that matters.  Any ideas, where should I start looking at the big board? 

Thanks,
Bryan

If it matters, the voltage tests for the small board were:
0A - 91.2
1A - 165.4
B-A/B - 0
1B - 166.2
0B - 86.3



Offline fullheadofnothing

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Reply #1 on: May 21, 2017, 06:09:23 PM
Are you sure it is reading 0Ω and not over limit? Does it display exactly the same reading as when you touch your red probe to terminal 12? Does the continuity beep sound when using that mode?

Joshua Harris

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Offline slackbits

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Reply #2 on: May 21, 2017, 06:36:39 PM
No.  Touching terminal 12 sounds, and is like .1Ω.  Touching OA and OB make no sound.  When I switch on the multimeter it shows 0.L MΩ - the same as touching OA and OB. 

Poking around here are some other resistance (with the black lead clipped to terminal 12):
R1A away from LED: 31.8
R1A closer to LED: 0.1
R1B away from LED: 31.8
R1B closer to LED: 0.1

R2A closer to R1A is all over the place like around 6M.



Offline fullheadofnothing

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Reply #3 on: May 22, 2017, 07:06:50 AM
OL means Over Limit. Your meter is displaying that there is infinite resistance between the two points, as it should be.

Joshua Harris

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Offline Doc B.

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Reply #4 on: May 22, 2017, 07:11:20 AM

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


Offline slackbits

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Reply #5 on: May 22, 2017, 01:53:12 PM
Thanks guys.  Once again it seems that my main issue is my multimeter and my lack of understanding of it.  I do have a question, the OA voltage reads 112v, is that too high?

OA - 112V
OB - 107V
G - 0
B+ - 171V



Offline Paul Birkeland

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Reply #6 on: May 26, 2017, 11:31:26 AM
My guess is that the OA and OB voltages on the small board up front are a little on the high side as well, which will make the OA and OB voltages on the big board a little higher than normal (not a problem though).

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man