A guide to fixing/troubleshooting some common plasma TV problems

[Jason 82]

Re: A guide to fixing/troubleshooting some common plasma TV problems

So not the z-sustain board. ?

[tom66]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Good catch didn't see that.

[capkid]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Agree with Tom. The Vzb is also low or not measured correctly. It should be 100V. When the fuse on the Y-Sus blows, it's usually an indication that the large IC under the big heat sink has shorted.

Video: http://www.youtube.com/watch?v=Y8MNQYXw8E0&sns=em

[tom66]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Your Vs is really low - unlikely to be your problem but do adjust it later.
-Vy and Vsc are faulty which indicates a Y-sustain fault.

[Jason 82]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Ok this is what I got
Vs-172.9
Va-55.4
VZb-.60
Vsc 1.26-9.94 fluctuated between these numbers
-Vy .7-1.5 fluctuated between these
Hope this helps us trouble shoot

[tom66]

Re: A guide to fixing/troubleshooting some common plasma TV problems

vinceroger69, thanks for the link there is some really good inforamtion here. thanks again..If anyone knows where i can get ccfl replacement tubes for sharp lc6554u sharp 65" i need ccfl. also if there is a way to trick the set into thinking it has the bulb please post or nessage me. I have one bad ccfl in the set and have moved it to the bottom of the screem but cant find a replacement and have a huge tv taking up space in repair area due to bad bulb..thanks jamie

Defeating the bulb detect can be done if you have a schematic of the inverters; do you? Best put this in your own thread.

[capkid]

Re: A guide to fixing/troubleshooting some common plasma TV problems

I would do the voltage checks to establish a baseline then worry about other possibilities afterwards.

[Jason 82]

Re: A guide to fixing/troubleshooting some common plasma TV problems

I changed the fuse that was blown on the toshiba and has not blown since, whst is the more complex issue?

[Jason 82]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Ok here are the pics of voltage

[jamie_ydr]

Re: A guide to fixing/troubleshooting some common plasma TV problems

vinceroger69, thanks for the link there is some really good inforamtion here. thanks again..If anyone knows where i can get ccfl replacement tubes for sharp lc6554u sharp 65" i need ccfl. also if there is a way to trick the set into thinking it has the bulb please post or nessage me. I have one bad ccfl in the set and have moved it to the bottom of the screem but cant find a replacement and have a huge tv taking up space in repair area due to bad bulb..thanks jamie

[Jason 82]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Will do in the Am. Thank you. I appreciate the help !

[jamie_ydr]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Tom. this is a great help. Thank you for taking the time to break it down..Although I do have a problem with a set that i am working on, that is real similiar to your posts.. I have a 50pfp5332d/37 and it came to me with sound and no picture. Normally i would do a little testing and then replace the x or y sustain boards.. Although I have been working to become more confident in component level repair. So guys with this being said voltages were a little off and i was thinking that something was dragging them down or bumping them up. so i've checked all fuses including the thru-hole and sm ..All fuses are good, so i was looking at the ysus and noticed that the voltage on the lower half was gone and like 1/2 of what things should have been.. Then I notice a mosfet or power ic 7 leg MR4720 is the part number marking and a pin is burned in half. so I have ordered a couple of them, only available from hong kong, and am waiting to see if this fixes the set.. I guess my question is DO YOU THINK SOMETHING OTHER THAN THIS PART CAUSED IT TO FAIL? I iwll let you know once that part arrives abd soldered in. Is there anything else I should look for? I will post a pic of the part and the location on the board tomorrow. thanks again jamie

[capkid]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Ok, here you go. The voltage checks are listed on the pictures I've attached. The black and red arrows denote the black and red probes. If there is no black arrow included for a test point, that means your black probe should be placed on chassis ground (a metal part of the back of the TV is fine). Post a pic of the panel label that lists the voltages so we can help you compare your readings to the label.

[Jason 82]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Yes, please do. I would much appreciate the diagram and I will check, I appreciate all the help. I'll stand by on ordering a z- sus board.

Thanks

Jason.

[capkid]

Re: A guide to fixing/troubleshooting some common plasma TV problems

You may have a faulty Y-Sus if the fuse blew. Here's what I'd do:

(1) Check all Y-Sus and Z-Sus fuses.
(2) Check all standard panel voltages:
Power supply: VS and VA
Y-Sus: VSC and -Vy
Z-Sus: Vzb (aka Zbias)

Edit:
If you're unsure how to do the voltage checks, I can diagram them for you tonight. Also, there are lots of threads that mention the voltage checks specifically for LG-based TVs like yours.

[Jason 82]

Re: A guide to fixing/troubleshooting some common plasma TV problems

I replaced one fuse on it and same issue.

[capkid]

Re: A guide to fixing/troubleshooting some common plasma TV problems

You can do a search on ShopJimmy.com to see if any substitutes are available.

[tom66]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Check fuse on it, usually you have to replace with same board.

[Jason 82]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Can I replace it with a similar board or exact board replacement ?

[tom66]

Re: A guide to fixing/troubleshooting some common plasma TV problems

Z-sustain fault.