HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

[capkid]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

You can take a fet from your old lower, but you need to test them first, obviously. If you're not sure how to test a mosfet, here are a couple different methods:

https://www.badcaps.net/forum/showpo...52&postcount=7

https://www.badcaps.net/forum/showpo...5&postcount=17

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

maybe i can rob a good FET from my old lower board and replace a bad one on the upper?

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

oh wait, the upper drv board ohms are low today, 88.3ohms and 77.6. bad FET on upper?

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

ya, thats where im measuring....do u have skype? lol

[tom66]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

On all FETs? What about across the two large pad connections going to the Y-sus?

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

no, infinite one way, 2.4megohm the other way

[tom66]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

Did you read near zero on some of the FETs?

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

I disconnected just the top YDRV and i get the same screen with top blacked out.

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

Hmmm...

I disconnected the ydrv bottom, and I get the same display as above, only the bottom half is black. Also the ohms of the FETs on the new board match the upper y-drv board.

Ldmme guess? I got sold a bad ysus board?

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

Hmmm...

I purchased a YSUS and YDRVBT board and installed them today.

Unfortunately, it didn't solve the all problems.

Now I have bright blue sparkling pixels all over the screen, with this white vertical stripe that moves to different positions left to right every so often.

Ya think I got a bad YDRV board?

[capkid]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

You can also use a service like "Coppell TV repair" on eBay who will replace your IPMs for $130.
http://www.ebay.com/itm/Sustain-6871...item255d4e1b2d

I'd set a limit in my head of $100, but that's certainly a quick and less dirty option. Coppell does good work.

[tom66]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

You can also use a service like "Coppell TV repair" on eBay who will replace your IPMs for $130.
http://www.ebay.com/itm/Sustain-6871...item255d4e1b2d

[capkid]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

Upon removing and inspecting, it definitely looks like some heat on Y-SUS around the upper IPM, clear residue and discoloration, around the ER_LOW pin area and the C5, C6, C24 area.

Not clear to me how to remove the IPM heatsinks, do you have to unsolder the IPM from the rear and get it off the board to remove the sink? There are screws that are holding the sink on that appear otherwise inaccessible.

The video link I provided earlier shows how to replace the IPMs. It's not an easy procedure without the proper equipment, and you have to be careful not to damage the traces and rings on the circuit board: http://m.youtube.com/watch?v=Y8MNQYXw8E0

Edit: If you decide to just replace the Y-Sus as a whole, it looks like you have a few substitutes available: http://www.shopjimmy.com/lg-ebr30597501-ysus.htm

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

Upon removing and inspecting, it definitely looks like some heat on Y-SUS around the upper IPM, clear residue and discoloration, around the ER_LOW pin area and the C5, C6, C24 area.

Not clear to me how to remove the IPM heatsinks, do you have to unsolder the IPM from the rear and get it off the board to remove the sink? There are screws that are holding the sink on that appear otherwise inaccessible.

[capkid]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

Good question. I might spend $100 to replace the Y-Sus IPMs and buffer fet for now. New TVs are very inexpensive now, so I wouldn't put much money into it.

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

If it was your TV, and you had the money to spare, would it be worth repairing?

[capkid]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

Its holding 111.4VDC

Ok, it's probably supposed to be 110V, which isn't far off. It seems to be working fine. The Y-Sus and lower Y-buffer appear to be the sole culprits.

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

Its holding 111.4VDC

[capkid]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

Is there a guide on how to check that Z-sus voltages are ok?

Check Zbias voltage across the R111 resistor on the Z-Sus - it should be somewhere around 100V. The panel label should have the exact spec.

[ngc1068]

Re: HP 50" Plasma TV, Model: CPTOH-0603... plz, need help troubleshooting

Is there a guide on how to check that Z-sus voltages are ok?