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Repair Log… (8/6/11)


MPU4 – PSU Fault - Fault diagnosis - PSU is dead.


Check fuses,  mains fuse is 13 amp, but good, remove and replace with 3 amp.


34 volt fuse meters good, but comes apart in the holder. Replace (after digging it out of the holder). Brown wire is melted, so start there.


Replace spade and spade cover. Re-cap PSU, replace C1, C2 and C3 also replace the bridge rectifier connected to the melted brown wire. No joy. OK, so I should have metered it. Replace the other bridge rectifier. The old bridge meters ‘open’.


PSU is now good.  Moral of the story... I will use my meter, I will not guess!!!! (The observant among you will notice that I also changed the primary transformer to eliminate it)