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+5V rail varies with accent pot?

Posted: Mar 9th, '15, 19:20
by buffo
Hi

I´ve built BD, SD and HT so far and they are working fine, however I just noted something strange when I checked +5V rail. When accent pot is between ~counter clockwise to 2 o clock, 5V rail measures 5.07V - fine. But when I turn accent pot more clockwise, 5V rail increases until about 6.5V!

If I disconnect IO board from main board all voltages are correct.

My electronic skills are very basic so I don´t know if this is wrong, but it didn´t seem right to me. Does anyone know if this is expected, or what might be the problem here?

Re: +5V rail varies with accent pot?

Posted: Mar 11th, '15, 15:31
by buffo
The alternatives I can think of are

1. Nothing is wrong, it is just the regulator that doesn't "work" without load (not sure if +5V has load before building sequencer step?)
2. Something is wrong with LM2596 (or components around it). I Can probably check this by using a lab PSU instead of the PSU board?
3. Something is wrong with accent section, but it seems unlikely to me that this would cause the 5V regulator to output wrong voltage?

Any ideas are very appreciated :) It doesn't stop me from finish all instruments, but I don't want to build the sequencer before knowing if this is a problem or not...

Thanks!

Re: +5V rail varies with accent pot?

Posted: Mar 14th, '15, 11:23
by e-licktronic
Dear Buffo,
buffo wrote:1. Nothing is wrong, it is just the regulator that doesn't "work" without load (not sure if +5V has load before building sequencer step?)
You're right.
Test +5V again when your sequencer parts will be built.

Best regards,
e-licktronic

Re: +5V rail varies with accent pot?

Posted: Mar 14th, '15, 19:50
by buffo
Thank you for your reply! I will test it again when sequencer is built :)

Re: +5V rail varies with accent pot?

Posted: Mar 31st, '17, 12:53
by makore
I'm having the exact same issue. +5v varies with accent pot prior to sequencer section build.

buffo - did it resolve itself once the sequencer was built? Or was there another solution?

Thanks!

Re: +5V rail varies with accent pot?

Posted: Apr 6th, '17, 17:23
by makore
For anyone having this issue - once the sequencer part is built this problem resolves itself and you should get a steady +5V.