Re: ProScan PLED5529A-C: No image, Backlights good
Yes 12V on both the power supply board and the main board. Ok since I get power on both sides, that means that the black connector is ok. I found out which pins of the connector cable (main board side) send power down to the surface mounted connector on the T-CON board. When the T-CON board is connected: the pins read 8V. When the T-CON is disconnected it jumps up to 12V.
If it is a bad switched MOSFET, any tips on how to ID the one affected?
good_ol_Wes
Member
Last Activity: 11-23-2017, 03:06 PM
Joined: 08-21-2017
Location: Portland
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Re: ProScan PLED5529A-C: No image, Backlights good
I inspected the solder joints of the black connector under magnifying glass. they all seemed to be fine. I measured the voltage on pin 13 & 14 on both mainboard and power board sides. when referencing the picture I posted, starting from the bottom (closest end to power cord) pins 13 are: 12V,3V 3.75V,0V,0V,0V,5V and is the same on both power and main board sides. I could not accurately measure pins 14, because of difficulty accessing the pins (I don't have steady enough hands to reach between the upper 13 pins to get to the...Last edited by good_ol_Wes; 11-18-2017, 07:30 PM.Leave a comment:
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Re: ProScan PLED5529A-C: No image, Backlights good
Yes Budm, you are correct. Digital voltmeter set to Volts DC, black probe touching chassis, red probe on either side measures 8.25-8.30 Volts. Where did you you find that information on shopjimmy.com? I looked all over the website and couldn't find details like that.
Yes I am positive that the LVDS cable isn't backwards because the connect only allows you connect one way. you cant flip it over and connect. you can flip sides on the main board side, but that does nothing but send 1 volt to TCon.
if Budm...Leave a comment:
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Re: ProScan PLED5529A-C: No image, Backlights good
ok with reference to ground I measure 8.25V across P2016, so it looks like Tcon is getting power afterallLeave a comment:
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Re: ProScan PLED5529A-C: No image, Backlights good
I checked the voltage going through P2016 = o.oV. I also tried removing one end of the ribbon cable, with no changes. tried the other side, nothing happened. its hard to tell if anything changes since the screen is black with no image on it.Leave a comment:
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ProScan PLED5529A-C: No image, Backlights good
I got my hands on a broken 55" ProScan LED TV. I used this site heavily to determine that the original issue was that there was a burnt out backlight LED that would cause all the Backlight LED Strips to fail/turn off. I replaced the backlight strips and put the TV back together. Now when I turn the TV on, no image shows during startup (not even manufacturer logo shows up) and the screen is black. it is very obvious that the backlight LED's are working perfectly fine and on, but now the screen will not show images. Before replacing the backlight strips, I was able to see images on the TV when... -
Re: 2 seconds then black: Proscan LED TV(PLED5529A-C)
OK so I went and took the rest of the TV apart to get to the LED backlight strips. I kept it plugged in and turned it on, and only the top half (3/6) LED strips illuminated. so i went and individually checked each LED on the backlight strips of the bottom 3 that did not illuminate. out of all the LED's on all 3 strips, there was 1 single one that was burnt out. So it looks like you guys were correct. will get my hands on a new LED or replacement strip and install it. that should do the trick right?Leave a comment:
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Re: 2 seconds then black: Proscan LED TV(PLED5529A-C)
OK I will take those measurements tonight. After talking with a couple electrical engineers i work with and describing the problem and the voltage readings i got, they suggested that it possibly sounded like a capacitor problem. They also suggested that i measure the resistance of the LED circuit and that if there is no resistance then that will indicate a broken LED. Do you think these could possibly be the issues? if so, how would i be able to go about figuring out which capacitor went bad? or how can I test to make sure that...Leave a comment:
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Re: 2 seconds then black: Proscan LED TV(PLED5529A-C)
it still doesnt measure a current going through the red wire at any part of the process. with the black wire it drops to -1.00, then jumps up to around 50v, then 12-18v, then back down to 0.60v. It seems to me that the black wire is the live wire and red is ground since it doesnt measure any voltage, but black does.Last edited by good_ol_Wes; 08-21-2017, 07:14 PM.Leave a comment:
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Re: 2 seconds then black: Proscan LED TV(PLED5529A-C)
looks like to power coming to the connectors, but how do the backlight LED's illuminate during the startup (before turning off) without allowing me to measure a current at the connectors? Does this mean that either there is a bad LED?Leave a comment:
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Re: 2 seconds then black: Proscan LED TV(PLED5529A-C)
i took 3 measurements of each side(left and right) with and without the connector attached.
with connector attached:
left side -
off: black- 0.612 , red- 0.00
start up: black- **** , red- 0.00
on: black- 0.601 , red- 0.00
Right side-
off: black- 0.605 , red- 0.00
start: black- **** , red- 0.00
on: black- 0.591 , red- 0.00
Without connector (3 prongs):
left side:
off: left- 0.60 , middle- 0.60 ,...Leave a comment:
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Re: 2 seconds then black: Proscan LED TV(PLED5529A-C)
I am having a hard time determining which connector you are talking about? is it the two ribbon cables leading from the T-Con board? Can you reference somewhere on the pictures i posted and I will be happy to measure and post voltagesLeave a comment:
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2 seconds then black: Proscan LED TV(PLED5529A-C)
Here is the problem:
I am able to turn on my Proscan LED TV, the power LED turns blue(meaning it is on) and an image of the Logo appears. Quickly after the screen goes black(about 1-2 seconds). I have not tried playing sound through it. I have put the screen in a dark room and have tried the flashlight test on it and I was able to see and navigate around the menu when the light was shined at a specific angle. I have done some research on what the problem could be and I believe that I need to replace the T-Con/LED Driver board. I believe this because the LED's illuminate for a second... -
Re: New Members - please post your introductions here
hey everyone, love the site and have been using it for some time for excellent repair info.Leave a comment:
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