Hitachi 55HDX62 will not turn on

[mikmar]

I have a Hitachi 55hdx62 plasma that died one day. I get no power from the power supply to feed the x sus and y sus board. When I turn the power on the green led for power lights up in the front. But I get no power out to the sus boards. I have not found Any components on the power supply that look fried. Please point me in the right direction. Thank you.

Mike

[mikmar]

So I measured the voltage out of the supply and found that for a split second after I turn the set on the voltage is at the output, but the supply is shutting down for some reason. I also found two different transformers that the secondary and primary connections are shorted together. I checked these transformers on the board so I am not sure if they would test good off the board. All other components look ok. Any suggestions?

Mike

[mikmar]

Can't find any bad components on the power supply. Caps all look fine, power transistors all seem to be good, schottky diodes seem ok. Not sure what the esr of the caps are since i don't have an esr meter but visually all caps look good.Anyone??????

[jts1957]

I've lost count as to how many parts I've replaced that still "look good."

Something has to be seriously wrong with a part, or there has to be a defect (i.e. short) that is causing the part to fail and "look bad."
Your eyes may help you to find maybe 20 percent of failed parts.

The best way to prove whether a part is good or bad is substitution.
The next best way is to test the part's important parameters with appropriate test equipment.

[minnie]

Shoot me a email and I'll send you a power supply trouble shooting guide. In this set you can have a bad dig. main not allowing the set to start.

[mikmar]

Thanks minnie,
I emailed you about the power supply troubleshooting guide. I appreciate the help and will post back with the findings.

[mikmar]

So I finally got this plasma fixed. With the help of the power supply force on guide and the DW1 troubleshooting guide that minnie sent me. I found the power supply to be working correctly. During turn on the vcego and vsago turn on voltages would shutdown almost immediately. I pulled the Ysus board thinking that was the trouble and checked all diodes, capacitors and transistors but did not find any components to be at fault. I then plugged the ysus board back in and unplugged all boards from the xsus and ysus boards that fed the panel. Low and behold my vcego and vsago turn on voltages stayed up and my power supply was again producing voltages. I plugged in one board at a time until the power supply shutdown came back thus eliminating all boards except one to be at fault. It came down to the bottom scan buffer board that was shutting down the power supply. Just to eliminate the panel being at fault I unplugged the ribbon connections going to the bottom scan buffer board and tried to fire it back up. I still had shutdown. YEAH!!!!!!!! What that meant was that the buffer board was the problem. I quickly located one for sale and ordered it. The board arrived yesterday. I installed it and now have my plasma working once again. By the way with shipping the board cost $90. Pretty darn cheap repair. Thanks to minnie for helping me out with the guides to help me get this thing fixed. This site is one of the best ever.
_________________
mikmar

[minnie]

Ain't rocket science!

[mbarvo]

minnie, would it be possible to get the power supply troubleshooting guide?
[email protected]