Electronic equipment repair and service manual search discussion :: Topic review - Hitachi 50V500A Power Supply Troubleshooting

crc2010 · Posted: Fri Mar 19, 2010 1:12 pm Post subject:

Ok, I'm registered. Thanks for your help so far!

minnie · Posted: Thu Mar 18, 2010 11:35 pm Post subject:

Register and I can send you a flow chart.

crc2010 · Posted: Mon Mar 15, 2010 2:50 pm Post subject:

Yes. The 300V ballest voltage is there. Is there a line I can check that will shut the power supply down? For example, the protection circuitry?

minnie · Posted: Mon Mar 15, 2010 1:43 am Post subject:

The power supply is a JT24163R R for rebuilt. I remember the voltage regulatotr is a common failure on the set also. You hazve the 300 volts at the ballast?

crc2010

Thanks for the post back. When the power button is pressed on the TV, the blue power LED is on. The TEMP and LAMP LED's are off. I haven't been able to check C958 yet. According to the schematic, it's a shunt to ground on the +10V supply line. I will try to check on the weekend.

minnie · Posted: Mon Mar 08, 2010 4:24 am Post subject:

Just looked, check C958 I'd assume it's on the power supply. Front LED's look normal but the set is not on. 1000uF/35V capacitor. It acts like the set is on, but it's not. Post back. I need to know the conditions of the light's on the front of the set IE power/lamp/temp. The LED's on the power supply can't tell me squat.

crc2010

Yes, the bulb has been replaced. When the power button is pressed, the blue power indicator lights on the front of the TV. I have verified that all the failure modes work based on the troubleshooting guide in the service manual (eg: lamp door, lamp module, high temp). The problem is that none of the various voltage indicator lamps on the power supply module are coming on. I'm wondering if the protection circuitry is shutting down the power supply for some reason. Does anyone know if there is a troubleshooting guide for Hitachi TV's? I saw someon on Ebay selling one but I'm not sure if it's the service manual or something different.

minnie · Posted: Sat Mar 06, 2010 12:01 am Post subject:

Did you try replacing the lamp?

crc2010

When I plug in my set, the main LED (red) on the PS comes on and the +5V (green). None of the other supply LED's come on. I hear the power relay clicking and the 300Vdc for the lamp ballast is present. Does anyone have any suggestions as to where I should go from here?