Proscan PLDV321300 Quick Flash Then Dark

[Michale32086]

Rolling with my new found courage to check voltages...

Proscan PLDV321300.. Once powered up, I see a quick flash of the screen, then it goes dark. Flashlight reveals the image is still there..

I found where the backlights plug into the main board (the ONLY board)... I put the pictured meter on those connections..

When probes first applied, I get a reading of around 31v-33v +/- with the TV plugged in..

Once I push the power button, the voltage spikes to as high as 70v... Then it settles down to around 40v +/- 3 or 4...

A replacement board is around $45.. Doable.. But if it's possibly a short in the LED strip, a replacement board ain't going to help me..

Once again, I am hoping that I can find the issue is on the board and not have to fiddle-fart with breaking the unit down to the bare backlights..

I stand ready to apply my probes...

[selldoor]

Re: Proscan PLDV321300 Quick Flash Then Dark

If the tv is working. picture and sound with only the back light missing odds are it is the
led strips. What is the part number on the panel- maybe you can find the configuration of the strips.

[Michale32086]

Re: Proscan PLDV321300 Quick Flash Then Dark

If the tv is working. picture and sound with only the back light missing odds are it is the
led strips. What is the part number on the panel- maybe you can find the configuration of the strips.

I was hoping to avoid going there...

But, as Mick Jagger said, "You can't always get what you want.."

[CapLeaker]

Re: Proscan PLDV321300 Quick Flash Then Dark

preliminary check: just take the LED connector that plugs into the board and see if something is grounded out or a bad connection somewhere. hold one probe to the metal LED frame. It does not necessary have to be a bad LED, even though it sounds awfully like it, I am afraid...

[selldoor]

Re: Proscan PLDV321300 Quick Flash Then Dark

Mybe 6 strings?
http://www.njytouchshop.com/boe-hv32...l#.VKxOfldAb4g

This might be useful -per budm
https://www.badcaps.net/forum/showpo...&postcount=107

[Michale32086]

Re: Proscan PLDV321300 Quick Flash Then Dark

Well, there is no direct short from the positive to the ground..

I guess I'll break it down to the backlights in the morning and see what I see..

Thanx for all the input..

[budm]

Re: Proscan PLDV321300 Quick Flash Then Dark

It looks like simple boost converter with single MOSFET, Inductor, filter cap, current sensing resistor, and one rectifier diode. It's probably does not have open LED detector due to only single string LED but it will have over current protection.
So remove the LED connector, check the DC Voltage on that filter cap's legs laying on its side to see what you get.

[budm]

Re: Proscan PLDV321300 Quick Flash Then Dark

It may have EEPROM problem since SJ sells EEPROM.
http://www.shopjimmy.com/catalogsear...can+PLDV321300

[Michale32086]

Re: Proscan PLDV321300 Quick Flash Then Dark

Thanx, BudM... I left the TV at the shop and am home for the night.. I'll be going in around 0400 EST and will follow up..

Thanx again...

[Michale32086]

Re: Proscan PLDV321300 Quick Flash Then Dark

OK, with the LED Connector unplugged...

I get 33.9v +/- on the small cap right by the LED Connector...

And I get 164v +/- on the large cap at the bottom of the pic...

[CapLeaker]

Re: Proscan PLDV321300 Quick Flash Then Dark

with the backlight plugged in, do you get the 33.9V, or does it go away?

[budm]

Re: Proscan PLDV321300 Quick Flash Then Dark

"I get 33.9v +/- on the small cap right by the LED Connector..." So it did not jump up higher than that when power switch is activated?

[Michale32086]

Re: Proscan PLDV321300 Quick Flash Then Dark

OK, I finally was able to double check this..

Dummy me.. I just checked the voltage when it was plugged in... Not when powered up..

Duuuuhhhhh

Anyways, the following video shows the power up process...

http://sjfm.us/temp/PLDV32.3gp

The long and short of it..

At power up, shoots up to around 111v and then slowly drops down to around 39v....

[budm]

Re: Proscan PLDV321300 Quick Flash Then Dark

Do you have 7.5K or 10K 1W resistor to hook up to the LED connector to simlate about 10mA of current flow?
It can also be that the BL_ON signal drops out, need to find that pin on the board to see if it is present or not.

[Michale32086]

Re: Proscan PLDV321300 Quick Flash Then Dark

Thanx BudM, Capleaker & SellDoor..

I appreciate all the good input. Unfortunately, we're prepping for our son's wedding tomorrow. I'll have a few hours at my shop in the morning, so I'll follow up with this then..

Thanx again..

[Michale32086]

Re: Proscan PLDV321300 Quick Flash Then Dark

OK, I have an hour or so to work on this...

Attached is the picture that shows how I have it set up...

And here is the result...

http://sjfm.us/temp/PLDV32-2.3gp

[cr4west]

Re: Proscan PLDV321300 Quick Flash Then Dark

My apologies for digging up an old thread but I have the same model
Proscan PLDV321300 / RCA 123882 with the single mainboard and am struggling to find the service manual. Found nothing on elektrotanya.com. I have power on indicator LED and backlight LED power. Next going to test for LED current flow and bad LED' S. Then going to look for BL-on signal and T-con status. Sure would be nice to have a schematic instead of stabbing around in the dark. I really enjoy the badcaps site. Would anyone be able help?