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Envelope/Gating Circuit peak test
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Envelope/Gating Circuit peak test

by Biggs7 on Sun Nov 05, 2017 2:57 am

Hello all, I'm building a WillZYX kit and I ran into a problem testing the gating circuit. I have no problems with the 12VDC at D35, but I cannot get 12V peak from the R3 trigger. I have visually inspected the pcb for poor solder joints and orientation of the Q's. I will try to start testing some components in circuit if possible. Any suggestions please?
Thank you!
Sincerely,
BIGGS7

Biggs7
 
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Re: Envelope/Gating Circuit peak test

by antto on Sun Nov 05, 2017 5:12 am

Biggs7 wrote:Hello all, I'm building a WillZYX kit and I ran into a problem testing the gating circuit. I have no problems with the 12VDC at D35, but I cannot get 12V peak from the R3 trigger.

R3 trigger? R3 is on the IO board, part of the circuit that makes the 5.333V voltage

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Re: Envelope/Gating Circuit peak test

by Biggs7 on Sun Nov 05, 2017 1:40 pm

Hello. Sorry for the confusion. Yes. R3 on the I/O board (5v) is the reference point that is used in the build manual on pages 56 and 57 to pulse 12vdc to D36, using a jumper wire from R3 to R146(gate I believe) and touching R3 momentarily to send 12vdc. I do not see this pulse ever.... I do have good 12vdc on D35 when a jumper is connected from R3 to R146. And I also have no voltage when the jumper is disconnected as normal...
Thanks again.
Biggs

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Re: Envelope/Gating Circuit peak test

by Biggs7 on Mon Nov 06, 2017 6:27 pm

Antto, any suggestions?
Thank you.
BIGGS

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Re: Envelope/Gating Circuit peak test

by antto on Tue Nov 07, 2017 1:16 pm

the signal at D36 should be a very short spike (probably about 1ms, don't quote me on that)
if you're measuring with a multimeter chances are very high that you won't "see" it
if you're measuring with a scope, make sure you've configured it to trigger properly so that it pauses when it catches the spike

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Re: Envelope/Gating Circuit peak test

by Biggs7 on Tue Nov 07, 2017 9:51 pm

Antto, thanks. I was using a dmm and I did see a bit of a jump, but never see 12vdc. I also tried to turn on the hold feature on my dmm, but i never see it or hear an audible beep. l do also have a scope which I just purchased. It's an older tek 453.... Still getting the hang of it.... I didn't think too much of this problem I'm having originally and I just noted it in the manual and kept on building. I've finished the vca now and when I try and do the test on pg. 61, I don't hear a note being played. I need to double check my headphone wires again, as there are 3 conductors. They are cheap earbuds... I do hear some noise when I rub the headphone wire around the rightmost pin hole of vr8 for the volume pot.... you have to use r146 again in this test, so I figured something was not right with the envelope gate section.... I'll try to see the pulse on the scope with it setup appropriately and let you know what I see...

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Please be positive and constructive with your questions and comments.