Hitachi Plasma TV Troubleshooting
FAULTS
- The green power LED is always ON.
- The power LED will go green and may go Off or stay ON.
- Green power LED will go green then go Off or may not go green at all.
THE GREEN POWER LED IS ALWAYS ON
- This indicates that the set is providing Vs and Va voltage to the X-SUSTAIN & Y-SUSTAIN PWBs. Use an analogue scope. Look at the outputs from X-SUS and X-BUS. Use the top pin of the connector going to panel, on either side.
- No activity usually indcate with a defective PWB.
- Pull the ribbon cable from that PWB to the panel, and check again.
- If there is activity now, the panel might be defective. In most cases, it is.
- Pull all ribbon connectors before condemning the PWB.
- If the panel is defective, in most cases it can be seen by the panel itself.
- If Top ribbon cable is pulled, the top of the screen will be black; but the bottom will have raster.
GREEN POWER LED GO GREEN THEN GO OFF.
- This indicates a load on the line.
- Pull CN64 connector feeding Vs and Va voltages to X-Sustain.
- Measure the resistance in [Ohms] from Va and Vs lines on each PWB.
- Low resistance value indicates a defective PWB. Normal reading should be of Mega-ohms. Using the diode mode on the DV/Voltmeter, there should be a brief charge time, then infinity. Note, if there is a charge on the line, the meter may show low. Pull the CN-68 connector and take the reading again.
- The line should now be infinity when reading the power supply pins for Va and Vs when reading the connector going to the X-SUSTAIN PWB.
- If a low is see on the connector , pull CN32 [bottom right hand plug on the Y-SUS board.
After the connector is pulled:
If low disappears, then the Y-SUS or SDR PWB has the fault. If low remains, X-SUSTAIN is faulty
Pull all ribbon cables going to the panel, one by one while reading Vs/Va pins. If the low disappears, the panel is defective. Before confirm, check SDR buffer too.
If low remains the Y-SUSTAIN and/or SDR PWBs are defective.
Will be continued on next post: