Issue with power supply (intermittent)

• yoctow

  Posts 2

  Joined: Jul 30th, '17, 23:33

  Aug 1st, '17, 04:38

  Hello,
  I'm wondering if anyone can assist. My power supply is a 16vac 1250ma 'wall wart' / 'power pack'.
  After completing the Power Supply section of the instructions and testing the voltage pads with my multimeter, all values were correct (+5v, +15v, -15v) I moved on to the noise section and all was fine when measuring the IC voltage before soldering it in.
  
  When the time came to measure the voltage before soldering in the IC on the Accent section, I noticed the voltage readings were all over the place bouncing from low 0.x values through to Overload. I assumed something went wrong when installing the Accent section, so worked my way backwards, first separating the main board from the power supply and testing the pads again. The voltage issue was still present. So I then went and measured wall wart directly (one pin inside the barrel and the other outside) and it returned a consistent voltage (although, it does read 18V, not 16V.... but it wasn't bouncing all over the place like it was previously)
  
  Then I had the idea that there was possible interference because I had my soldering iron and the wall wart for the yocto plugged in to the same power strip. When I turned off my soldering iron, I got voltage readings again on the pads. I connected the main board again and got voltage readings on the pads for the Accent section, and proceeded to solder in the IC, assuming that somehow my soldering iron had interfered with it.
  
  The next day I worked on the Bassdrum section and once again when the time came to test the voltage on the IC pads, the voltage readings were all over the place again - this time I'd turned off the soldering iron - so it seems I have a bigger issue.
  
  I dont think the wall wart is the issue because every time I measure it with the multimeter it returns 18V (although, that seems a bit high. Is that the issue here? When I test the circuit it shows ~15V, so the power supply circuit board seems to do its job WHEN it works.) I've attempted to reflow the pins on the power jack - this worked and allowed me to get the IC for the Bassdrum soldered in, but after that when I tested again, the problem was back again.
  
  Does anyone have any ideas what the issue could be here? What other components on the Power supply board should I try to test?
  
  Thanks in advance!
  W

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