Author Topic: Williams WPC Driver / power supply board repair  (Read 9415 times)

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Offline beaky

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Re: Williams WPC Driver / power supply board repair
« on: April 12, 2011, 09:01:54 PM »
I started on the low +5vdc problem first. Caps (C5 & C4) and bridge (BR2) have been changed on this board for the +5v circuit. But c4 was a 1000uf where the schematic says 100uf and they have added a .01 monolithic capacitor across the GND and +5v out so I am assuming they have had a low 5v problem before and tried to bring the voltage up. I changed c4 back to a 100uf and checked the other cap and bridge So the only thing that is left is the LM323 (Q1) 5 volt regulator. It has a perfect 5v with no load but with a 250ma load it drops to 4.8V and of course with a bigger load it drops even more. I will keep you informed of the out come.
« Last Edit: April 13, 2011, 11:42:12 AM by beaky »
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