TV REPAIR GUIDE: How To Repair Emerson 32” LCD TVWith No Power And Shutdown Symptom

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How To Repair Emerson 32” LCD TV With No Power And Shutdown Symptom

The first problem was no power at all (no indicator light) so I inspect all of the diodes in the power area and found 2 shorted diodes D503 and D505 and both were 1N5406. I replaced the diodes with exact part number and now the TV could power on but picture shutdown and sound is good. I knew this was a backlight problem, so I tested all the transformers on the inverter and found 2 high voltage transformer that were open at the primary T1100 and T1050. I replaced both with exact type and now picture comes on and then shuts down again after less than 1 minute.

I continued to test and trace and found a bad mosfet Q1102 (22N055). It was tested good out of circuit but when under full operating voltage the mosfet would fail. By replacing the 5 components- 2 x Diodes, 2 x High Voltage Transformer and a Mosfet cured the problem. I left the TV on for 5 hours for burnt in test and the TV worked perfectly good.

Here is a tip for you- when using an analog meter in the OHM scale (x10K) the test lead voltage polarity is switched, this means the positive lead (red) is negative voltage, and the negative lead (black) is positive voltage. The test lead voltage in (x10K) scale is 13 volts

 

which is very good considering this meter only cost $49.00 from MCM Electronics. This voltage is very good for turning on various components, but for some diodes this voltage can damage the PN junctions.

This article was written by Damon from the beautiful place Maryland USA. His position now is Senior Electronic Technician (TV Repair) and soon will be involve in the robotics technology. He has many secret repairs he’d done on plasma/LCD TV and he need to find the time to write it and post it on his websites. He welcomes any technician or engineer who is willing to connect and share information concerning electronic circuits, component science, and R&D.

Here are two photos of all the TV's that he need to repair-its a lot, in fact over 700 plasma and LCD TV and over 200 DLP TV and Rear Projection TV's to fix.