Old plasma help.

[Inssomniak]

Hey all.
I have a 42HDT52A Hitachi tank of a plasma. Yes it's old but I have a thing for old plasma TVs.. Lol.

Panel is bright, and colours are nice and sharp, but there's a static or noise on the screen, particularly where the colours are changing brightness. Happens on the menus as well. (See pics). Adjusting the brightness has this weird dithering look to it as well (pic attached) Checked voltages and are ok as far as I can tell. Attached a couple pics. Examined all caps and everything looks ok. This seems to be a well built TV.

[Tvbob]

Re: Old plasma help.

Try heating up Y and Z sus, Power and Logic boards one at a time with a heat gun (not a paint striper) or use a hair dryer

[Inssomniak]

Re: Old plasma help.

Ok I can try that. I have noticed after its been on a while it does improve.

[R_J]

Re: Old plasma help.

Check the Vs & Va voltages, that might give a hint as to where the problem is.

[Inssomniak]

Re: Old plasma help.

Check the Vs & Va voltages, that might give a hint as to where the problem is.

I did and they were out a bit but when adjusted to spec it made no difference 😕. The tv has a Vw voltage on a sticker but can't find that anywhere.

[mmartell]

Re: Old plasma help.

Put the set in Test Pattern mode and see if the same anomaly shows up. This will at least rule out the main board as a suspect.

[R_J]

Re: Old plasma help.

The VW voltage is produced by a dc-dc converter on the Ysus board, The test point is not marked and I don't believe it is adjustable.
Check the software version, It should be 0116.0001, an update may or may not help

[Inssomniak]

Re: Old plasma help.

The VW voltage is produced by a dc-dc converter on the Ysus board, The test point is not marked and I don't believe it is adjustable.
Check the software version, It should be 0116.0001, an update may or may not help

I downloaded the latest firmware from the hitachi site, but it wasn't a version that high. Do you know where I can get that version?

I did find a test point for the Vw voltage on the ysus board, it reads 190 volts, but the sticker states 179.5 volts. No adjustment

[Inssomniak]

Re: Old plasma help.

Put the set in Test Pattern mode and see if the same anomaly shows up. This will at least rule out the main board as a suspect.

I dont have the service manual nor can I find one online, I also dont have the remote.. Any ideas on how to do the test mode?

[R_J]

Re: Old plasma help.

What version is on the tv now? My mistake on the correct version, the latest version for the "A" model is 0105.0001 (42hdt52A uses a different panel then the 42hdt52)
As for test mode, I don't believe there is one (he is thinking of lg auto-gen)
the service manunal is not that helpfull as they don't provide schematics of any of the panel boards
The manual is for the 42hdt52 (A2 panel) the 42hdt52A (A3 panel) is the same except for the firmware.
I tried uploading the 14M manual but the site gives an error
Try from here
As for the higher VW voltage, it might be the output cap for that dc-dc supply is weak, or it could be something else, hard to be sure

[Inssomniak]

Re: Old plasma help.

What version is on the tv now? My mistake on the correct version, the latest version for the "A" model is 0105.0001 (42hdt52A uses a different panel then the 42hdt52)
As for test mode, I don't believe there is one (he is thinking of lg auto-gen)
Here is the manual, they are not that helpfull as they don't provide schematics of any of the panel boards

Thats the version I have now, I installed a few days ago.

I found and checked a test point for Ve voltage, and I am under the understanding that this should be somewhere around 100volts? I am only reading 15.6 volts at this point, on the X board.

[R_J]

Re: Old plasma help.

I found the VE test point on the picture, It comes from D331 correct?
I found a different hitachi manual that lists the VE voltage of 17V (page34)
It looks like there is also a test point for VW near CNX01 plug
What do you measure on the lower white plug which has a pin marked -VE

[Inssomniak]

Re: Old plasma help.

Thanks for the info and assistance up till now.

I had to stop troubleshooting but I had a look through the pdf and saw a spot about troubleshooting and came across “steps of gradients are missing, logic board”. This describes exactly what the picture is doing. Steps of colour/BW gradients are definitely missing.

[mmartell]

Re: Old plasma help.

You have to place a jumper between two pads on the control board and unplug the main board lvds cable. When you power the set it will cycle through test patterns on its own.

[Inssomniak]

Re: Old plasma help.

You have to place a jumper between two pads on the control board and unplug the main board lvds cable. When you power the set it will cycle through test patterns on its own.

Yes I read that can be done, but I don't believe it can with this board, and if so, there is no info that I can find to enable this test mode.

[R_J]

Re: Old plasma help.

.

[Inssomniak]

Re: Old plasma help.

Duplicate

[Inssomniak]

Re: Old plasma help.

Similar enough to that. Different form factor.

[mmartell]

Re: Old plasma help.

I don't see it either. Nothing in the SM about it ?

[Inssomniak]

Re: Old plasma help.

I don't see it either. Nothing in the SM about it ?

Nothing.