Repair RCA DVD Player power supply

Date: January 2013

Problem:

An 120V DVD player brought from the U. S. was mistakenly connected to a 220V source and damaged its power supply by its previous owner.

Diagnosis:

The main electrolytic capacitor blew up with its top completely open from the excessive voltage pressure built inside. The fuse was also blown. These are just from the visual inspection of the most obvious damages. On the DVD circuitry, I did not find any obvious damage and I was hoping that the damage is limited to the power supply.

 

Repair:

After replacing the blown fuse and capacitor, the fuse would blow repeatedly each time it is plugged into 120V power source, which means there is a short circuit somewhere. The class X2 capacitor (yellow) is not the problem as it should stand up to 2500V of surge.

The next step is the bridge rectifier which is made of four diodes. I desoldered each one of them from one leg at the connection to the PCB, and did a continuity test with my multimeter. It turned out one of them is conducting both ways. A diode should only conduct one direction while blocking current from the other direction. That diode caused the short. I replaced it.

 

Result:

With the new fuse and diode, the DVD player worked once plugged in, and the DVD circuit is fine as all functions are normal.

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