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  1. darren adcock

    MFOS VCO fault

    I reads 12v
  2. darren adcock

    MFOS VCO fault

    Hi Alec PIn three measures, Blck probe on ground red probe on pin 3 =0.034v Black probe on -12v red probe on pin 3 =12v
  3. darren adcock

    MFOS VCO fault

    thanks, i will follow your instructions tomorrow at my workshop and report back. d
  4. darren adcock

    MFOS VCO fault

    Here is how I have my power supply set up for ground reference. Best to make sure I have done this correctly.
  5. darren adcock

    MFOS VCO fault

    Hi all. Alec T the capacitors were fine, thanks for sharing how to check them. I have a proper bench supply now that's set up for -12v/+12v at 20ma, thanks everyone who's been trying to help and being patient with my power supply problems. I'm hoping you can help further diagnose what has...
  6. darren adcock

    MFOS VCO fault

    Recieved this reply today from Soundtronics support. Hopefully it may help. However I expect you guys know this already. I'm assuming further diagnostics need to wait until I can connect power now? "Hi Darren, The sine is a modified tri wave form so if Tri is not working then the sine will...
  7. darren adcock

    MFOS VCO fault

    Hi Alec T. How would I check this please?
  8. darren adcock

    MFOS VCO fault

    Yeah I read the prefiltering was over the top, but was being indulgent getting to use such giant caps It's not supplying an audio amp aswell Yes I get (got) +12vdc -12vdc on the regulators output. I'm unsure what you mean by 'each set'. Does the 10-15 ohm resistor provide the 1a load?
  9. darren adcock

    MFOS VCO fault

    The bench power supply I have ordered has short circuit protection and a variable current limiter. Would your advice of the series resistors still apply? I will have to wait until i get my new power supply on weds to begin testing as the transformer I have is dead now.
  10. darren adcock

    MFOS VCO fault

    The caps check out on my meter reading as 10uf. The units power supply. I used this transformer. https://www.maplin.co.uk/p/3a-acac-fixed-voltage-12v-power-supply-n57dl And the MFOS wall wart power supply.
  11. darren adcock

    MFOS VCO fault

    The coarse pot didn't perform as it should. It would only manage low frequencies when repeatedly turned to clockwise and then tentatively turning it back to get the lower frequencies The PWM pot also miss behaved, It would let me hear sound in a very narrow part of the pot adjust at 12'oclock...
  12. darren adcock

    MFOS VCO fault

    It isn't no as the connector only allows it to be connected one way
  13. darren adcock

    MFOS VCO fault

    the insulation on this terminal block is fine. I just removed the connectors i've circled in white below. It has changed the resistance from R1(1) to ground from 6.4k to 9.5k.
  14. darren adcock

    MFOS VCO fault

    Ok. It was U6 that went up in smoke. I have remembered that i altered the wiring so i could recieve power via a terminal block instead, https://www.soundtronics.co.uk/12a-3-way-terminal-block-plug.html I can't think of anyhing else.
  15. darren adcock

    MFOS VCO fault

    It initially worked fine. It was simply sat on my shelf. I then tested it with a VCF module and found it was only effecting the freq cv as a saw wave. Here is a list of events; Worked fine, fully calibrated with Oscilloscope. Plugged in to test with VCF only to hear it controlling the voltage...
  16. darren adcock

    MFOS VCO fault

    Yes the ground is connected, is ground correct rather than 0v? Here is the board. Not great photo's I will take better ones in the morning if needed
  17. darren adcock

    What is your troubleshooting sequence?

    Ooo i didn't know those PCB burn marks could be that pesky. Good to know. Thanks
  18. darren adcock

    MFOS VCO fault

    Hi all. I've ran into a fault with a home built VCO module which I can't seem to locate. When I plug in it's power supply -12v +12v 3a it shorts across it's rails. I went to buy a new power supply today as I thought it must be that, i checked the supply befor plugging it in and there was no...
  19. darren adcock

    switch or patch

    Thanks. That'll be tonights research.
  20. darren adcock

    switch or patch

    I'm wondering if there's a way to use switches rather than patch sockets in modular synths? I'm guessing not as I would have probably seen it on synths, preferrably analogue. I'm imagining a set of switches that can overide each other, I'm also imagining a matrix nightmare! Happy with patch...
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