Author Topic: No 5v WPC  (Read 728 times)

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Offline beaky

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Re: No 5v WPC
« on: May 13, 2011, 10:46:06 AM »
Ok, if you follow Nino's advice and fit jumpers to all the above then the next thing to do is check the +5 volt without a load. (also make sure you have changed C4)
I usually do this on a bench test but you can do it in the machine by only connecting the correct plug to J101.
next test the +5 volt rail and see if you have +5 volts.
If you don't and everything is fine before the regulator then the regulator is cactus.
If you do then you will need to put a load on the +5v rail to make sure it still works under load, I do this with a 906 wedge lamp. (pins 4 & 5 0n J114, see photo below)
If the lamp lights up (it will only be dim) you still have between +4.9v and 5V then your reg is fine. If the voltage drops below 4.85 then the +5 reg is faulty.
If the reg has tested ok then power down the machine and hook up all the plugs then power up again. if you don't have +5v then there is a short or a faulty component on one of the other boards.

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