sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

[arman960]

I am working on a Sanyo 42" Plasma tv wich has bad Y-SUS and lower buffer board. TV would not turn on, get 12 blinks continuously. I suspect either BAD IPM or short Mosfet on it. I checked everything else ok. Can anybody tell me how to test this Mosfet with digital multimeter, without removing from the board.

I also checked IPM on it Model: STK795-518

But I am kinda confused about this IPM test which I found here below link:

http://blog.coppelltvrepair.com/2011_04_01_archive.html

according to this link SUS and ER should not short. But I found mine shorted with multimeter. But my x-sus is ok, and it has the same issue. do they suppose to have continuity or not. I am kinda lost. I think they are grounded.

Whenever I connect the T-con cable the power led starts blinking. But with that cable connected to Y-SUS I get a solid LED on power board. Also I get solid LED on power board with X-SUS connected only. So I think there is some kind of short on the Y-SUS.

My question is is my IPM BAD?

[retiredcaps]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

But I am kinda confused about this IPM test which I found here below link:

http://blog.coppelltvrepair.com/2011_04_01_archive.html

according to this link SUS and ER should not short. But I found mine shorted with multimeter.

List your results for all 6 tests as the blog states.

There are 4 inputs/outputs which result in 6 possible tests (Vs-GND, Vs-SUSout, Vs-ERout, GND-SUSout, GND-ERout, SUSout-ERout)

If you have a manual multimeter, put it on the 200 ohm setting. Don't use continuity for checking for shorts. Unless you know the threshold at which your buzzer beeps, it is a very inaccurate way to test for shorts. For example, there is one Mastech multimeter that will beep continuous for anything less than 1800 ohms. I would argue that a component that measures 1700 ohms resistance is not shorted.

[retiredcaps]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

@arman960, This is mandatory reading for you.

https://www.badcaps.net/forum/showpo...0&postcount=58

[arman960]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

ok. My bad. Here is the result of the outputs:


D5V= 5.1
Vg=32
Ve= 170
Vs=454
Vset=421
Vscan= -0

is it normal to Vscan to be -0?

[arman960]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

I need help. Anyone please. My Vscan =-0 , is it suppose to be normal. Now I am thinking there is soemthing wrong with my power supply. Wit X-sus power supply lid solid. But whenever I connect the y-sus the power supply LED starts giving 12 Blinks.

[arman960]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

hello, is anybody there?

[tom66]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

Vscan is generated on the Ysus.

[arman960]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

tom66. Thanks for the reply. So this is normal I guess that I am not getting any output from power supply for Vscan.

My IPM on Y_SUS looks ok. Since fuse is not blown. But obviously my y-sus is defective since I get 12 blinks whenever I connect the y-sus to the power supply.

Is there any way to test the 7 output mosfet with a digital multimeter?

[tom66]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

I have to admit I've never seen an IPM fail on a Samsung; I haven't repaired many, but no-one here has reported it. I'm half thinking even if it did fail, you wouldn't find a replacement. Vscan may be the plasma output drive, not necessarily active unless everything else is working... LG calls it Vscw and Panasonic calls it Vscn, but I can't be sure if Samsung is Vscan or not.

You can test for continuity between all pins of the IPM module. You shouldn't have shorts between the main power connections. You can do this on the board itself.

[arman960]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

according to this website there should not have any continuity between SUS and ER output. But with my meter I see continuity. Same with X-SUS IPM. My X-sus is good.

There is not short in these two pics also.

I just need to test the output mosfet than On this power board it says Vscan.

[tom66]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

You can test any normal MOSFET easily:
http://www.4qdtec.com/mostest.html

[arman960]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

tom66, it seems like the mosfets are ok. Do you know if there should be any continuity between ER ans SUS ? I have this character in Y-SUS and X-SUS.

[tom66]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

I can't be sure but if you check the PCB and they are separate traces you can be fairly sure there should not be continuity. I've never worked on a Sammy with an IPM, so can't offer much help - sorry!

[arman960]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

I bought one good Y-SUS and buffer. I will compare the old one with the new one and post the result. May be I will find something there to learn.

[arman960]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

tom66, I have this tv with this picture. Do you have any idea what might be wrong. Buffer or sustain?

[tom66]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

Buffers... assuming all the supplies are OK (Vs, Vscan, Va etc. etc.)

[arman960]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

both buffers? upper and lower?

[tom66]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

Usually one buffer can affect the other and Samsung make it difficult to isolate one or the other. The buffers for this TV should be pretty common and cheap though. They are used in lots of older TVs.

[arman960]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

Usually one buffer can affect the other and Samsung make it difficult to isolate one or the other. The buffers for this TV should be pretty common and cheap though. They are used in lots of older TVs.

Is this buffer issue or something else?

[tom66]

Re: sanyo DP42746 Plasma TV 12 blinks with Y-Sustain Connected

It looks like it.