Guys, wonder if anyone has run into this issue and has a solution. I have a Samsung PN42C450 plasma which had a couple issues causing it to fail. I determined the X sustsin was bad and also the buffer board had a shorted chip. I replaced these with tested used parts and also checked the y sustain which was still good. During the testing phase I saw that the VS and VA on the power board registered 290 and 79 roughly then shut down due to the bad x sustain. I pulled another PS from a another unit I had with a bad panel. Sill the same thing. I turned both down but the lowest they would go was 270 for VS and 61 for VA. I ordered another board off EBAY and guess what, the same. With all the new boards installed the TV turns on fine but still cannot turn the voltage down to match the screen voltage which is like 207 for VS and I think 50 for VA. All three power boards turn the TV on fine but all have the exact voltage issues where VS and VA cannot be turned down to the screen specs. Before I tear into the board and possibly order another board, has anyone else run accross this in this line of TVs which include the PL, PN, and PS series?
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Re: Samsung PN42C450B1 Power Supply issues
okay are you actually getting a picture like this when your VA is high you can easily damage the panel be real careful with this. Try adjusting voltages with the y sustain and z disconnected from circuit.Did I leave the soldering iron on? -
Re: Samsung PN42C450B1 Power Supply issues
Check your multimeter battery is not dead. In fact best to replace it outright.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: Samsung PN42C450B1 Power Supply issues
Thanks. Yes, I did not run the TV but a min or two knowing that the high voltage could damage it. Still stumped on what the issue is. I know my batteries are low on my fluke and will change tonight an also check some of the power board componets.Comment
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Re: Samsung PN42C450B1 Power Supply issues
tom66, thanks for your help, turns out the low battery in my Fluke was causing false readings. Really feel stupid but thanks. I should know by now to always check your equipment and never assume.Comment
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Re: Samsung PN42C450B1 Power Supply issues
The newest generation of Fluke multimeters will actually display bAtt on the display and not display a reading until you change out the battery.
I bought a "non working" Fluke 175 (firmware 1.x) and while it does display the low battery icon, it still gives readings, albeit erroneous (typically high). The Fluke 170 series with firmware 2.x displays bAtt.
PS. I use all my "dead" 9V batteries in the older generation 70 series which gets 2,000 (two thousand) hours of battery from a new 9V battery. It only draws about 250 uA in operation.--- begin sig file ---
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Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming... -
Hey everyone,
This power supply board is hard to find but there are repair kits available. This board had a blown fuse, FP801S, blown PFC MOSFET, QP802CS and ceramic cap, CP809. I replaced them with parts I already had and tested the rest of the parts that would've come in the repair kit and they were fine. I powered the board up on the bench expecting, in typical Samsung power supply board fashion, to see all my output voltages but, nothing. 0 volts on CNL801, CNM801 and CNT801. The only thing I have is 170vdc on the filter caps. No standby voltage either.
Anybody... -
I did not have any 27uf @ 50 volt capacitors but one nice thing is that it has enough room for two capacitors in parallel a 22uf and a 4.7uf @ 50 volts 22 plus 4.7 equals 26.7uf which so very close to 27uf I will show some pictures of it sometime tomorrow
This is one of the shit est boards I seen in a very long time and it was the daughter board the traces just lifting off the board I had to use the capacitor leads to repair the the traces and the main board is not any better because I had to repair several traces for the daughter board to the main board
After all of... -
I am attempting to test a samsung power supply board to verify the pfc ic is working. I am powering up the board with my isolation transformer. The board turns on fine but when I attempt to connect the ground for the scope probe, it trips out the isolator. I was taught not to 'float my scope' so I am wondering if I should test without connecting the ground lead or would that be asking for trouble? Not sure how else to test, I don't have a portable scope. I could plug direct to mains power but that would bypass the safety factor.
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Hi,
I have this almost brand new Plasma was well stored. I would like to repair it for a friend of mine.
I have noticed that it works for few seconds then switches Off the Power_ On signal. Have disconnected boards and left maion board and power supply and still the same. The power supply with PS_ON and VA signals On stays on so it is not a problem in the power supply.
Any one met this problem in the past?...10-08-2025, 07:34 AM
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