42" rca 42pa30rq no picture but sounds working

[sfdskins]

Hello everybody.
Got a problem with my rca plasma. came in the room with the tv on and found the picture was dead on the tv. sound was still working. with some help(service manuals) from Tom66 . thought i would try and fix it myself.
First off, when you plug the power into the tv, when it was working and i hit the power swich and you would hear one click from the power relay and the picture would come up. Now when i turn the power on, its one click, the several clicks on & off.
I checked for operating voltages at connector(cn804, to the y-main board) but no voltage present except the 15 volt.
I can pull this plug and it goes back to one click from the power relay, not sure if this means anything or not was going by the troubleshooting guide.

I did manage to find a component on the y-buffer board that appeared to be burnt,

im at a stand still now any help would be appriciated.
Thank you in advance.

[tom66]

Re: 42" rca 42pa30rq no picture but sounds working

Can you show a picture of the burnt component? This plasma is essentially a Samsung re-badge.

[sfdskins]

Re: 42" rca 42pa30rq no picture but sounds working

here is a pic of the component, it was under some silicon so i noticed the black spot and cut away the silicon to inpect it. its on the y buffer board.

thanks

[tom66]

Re: 42" rca 42pa30rq no picture but sounds working

Test across those caps, deos it appear short circuit on ohms? (With power off.)

[sfdskins]

Re: 42" rca 42pa30rq no picture but sounds working

it wasnt a dead short but did read about 10 ohms,

[tom66]

Re: 42" rca 42pa30rq no picture but sounds working

I would advise replacement of the buffers - they are generally quite cheap because this model is ubiquitous, I believe they are also used in PS42B450 and PN42B450 if that helps.

[sfdskins]

Re: 42" rca 42pa30rq no picture but sounds working

I was thinking about replacing the buffer board and the y main board but ill try the buffer board first, I believe i can get it for about 15 bucks, shouldnt be too bad
Thanks Tom

[sfdskins]

Re: 42" rca 42pa30rq no picture but sounds working

i replaced the y-buffer board (along with the logic board & the x-main sus board, got them for a good price)
still has the same problem black (dead) screen no picture, but sounds still working.

What im noticing is i cant read any voltages when i first power the tv and when i hit the power button, it the relays on the power supply board will click a couple times normally it was one click when tv was working. It does go to 15 volts dc but once the clicking stops it steadily goes down to 0. no other voltages present at any time.
Could it be a y-sus or power supply problem?
i can pull the power plug to the y-main board and the relays act normal just one click.
Thanks

[tom66]

Re: 42" rca 42pa30rq no picture but sounds working

Sounds to me like the buffers damaged the Y-main; do you want to board swap or try and find the failed component?

[sfdskins]

Re: 42" rca 42pa30rq no picture but sounds working

i wouldnt mind finding the bad component in case it does it again, but i will probably order a Y MAIN and try that to get it going, there is no physical damamge on the y board. i dont have a scope although i have access to some at work, getting to use them is another matter all together.

Do you think there is any need to get a power supply board when i order the y board?

Thanks

[tom66]

Re: 42" rca 42pa30rq no picture but sounds working

Unplug Y-main and check Vs voltage; if it's stable around 190-210V, PSU is probably good.

[sfdskins]

Re: 42" rca 42pa30rq no picture but sounds working

Tom,
i upluged the y-main power plug and checked the voltages, The excess clicking from the relay stops when unplug it by the way ,sonds like normal operation, When i cut the switch on, Vs voltage goes to a steady 207vdc and Va goes to 54vdc also steady, but after about 5 seconds the voltage starts to drop out or dissapate slowly to 0, this maybe be normal because where it doesnt see the y-main board? not sure.

[sfdskins]

Re: 42" rca 42pa30rq no picture but sounds working

Thanks for your help tom,
I got the y-main board in tonight, and that was the problem. My thinking on it is the y buffer board cap that was burnt, shorted out and took out something on the main board. what do you think? i had to reseat some connections to the ribbon cable on the buffer board because when the screen first came up had some black bars in line with the connections, was able to get that out and picture looks great now.
Might would like to look into it more and find the bad coponent on that board at some point but not ready to do that just yet,
Again thanks for you help on this, i learned alot about how thew tv works and feel cofident i can fix it again if i have another problem. Couldnt have done it without your help and the service manuals you got for me.

[ezm420]

Re: 42" rca 42pa30rq no picture but sounds working

Hi sfdskins I have the same TV and same problem. Could you please tell me were you purchased your new boards? And think you for your posts they helped a lot.

[capkid]

Re: 42" rca 42pa30rq no picture but sounds working

Shopjimmy.com is your best bet. Their boards come with a 6-month warranty: http://www.shopjimmy.com/catalogsear...lt/?q=42pa30rq

[dwdurko]

Re: 42" rca 42pa30rq no picture but sounds working

Can you advise where to obtain a service manual for this model 42pa30rq

[tom66]

Re: 42" rca 42pa30rq no picture but sounds working

No direct SM available, but the PN42B450 is a similar model and the service manual should be OK for that.

[Louis82]

Re: 42" rca 42pa30rq no picture but sounds working

Hello, I have a samsung pn42c450b1 that has no picture, no sound, it only clicks. Based on all the threads that i have read here, this tv has same circuit boards as RCA 42PA30RQ. I followed what some people have done and has worked them is replacing all 3 circuit boards. Y buffer, Y main and X board and still have same problem. At beginning i found that buffer board had a dark dot on a capacitor, removed glue and of course was physically burned.

Anyhow, i replaced all 3 circuit boards and still same. Any suggestion guys ? Is it possible that paylesscomponents.com sold me a defective board or is this a panel problem.

Thank you for your time and help.

[capkid]

Re: 42" rca 42pa30rq no picture but sounds working

Hello, I have a samsung pn42c450b1 that has no picture, no sound, it only clicks. Based on all the threads that i have read here, this tv has same circuit boards as RCA 42PA30RQ. I followed what some people have done and has worked them is replacing all 3 circuit boards. Y buffer, Y main and X board and still have same problem. At beginning i found that buffer board had a dark dot on a capacitor, removed glue and of course was physically burned.

Anyhow, i replaced all 3 circuit boards and still same. Any suggestion guys ? Is it possible that paylesscomponents.com sold me a defective board or is this a panel problem.

Thank you for your time and help.

When you installed your replacement boards, did you install them all at once?

[Louis82]

Re: 42" rca 42pa30rq no picture but sounds working

When you installed your replacement boards, did you install them all at once?

Yes i did. Thank you