Teac 42" plasma, no picture no sound

[osci]

Hi all,

This is my first post, well second, I was given a Teac 42" plasma Model PLMSDM1060, which I knew at time of receipt didn't work. The set has power but no picture & no sound.

I pulled the back cover off & checked for anything visually, I replaced all fuses and further inspection found a blown cap #c16 on the zsus board.

Also discovered that this Teac model uses LG panel & boards (shock/horror)

Panel number PDP425V52330, I searched this forum for teac plasma's and didn't find that much info and then search for LG plasma's and found a wealth of information.

My problem is no picture or sound, the info I have gleaned tells me that the easiest fix is to replace the zsus + ysus + upper and lower buffers, however, the age of this model (5 - 6 yrs old) suggest the boards may not be available or if they are, they would be second hand.

part number of the boards (all LG)
zsus - 6870qze009h
ysus - 6870qye007h
top buffer - 6870qde010a
btm buffer - 6870gfe010a

I'm located in australia and have searched OZ ebay without success, US ebay list only a very small handful which are sold as is/used.

As I said above with the age of this model there is good reason to suggest that I may not be able to source the boards, which leaves the option of repairing the boards.

From the LG info I have searched on here (correct me if I'm wrong) seem to suggest that the IC on the boards can be replaced but this is no easy job by any means, what further complicates this is I have virtually no experience in tv or plasma tv's for that, but would love to try and fix this albeit if I could find the boards or repair the boards.

Again from the information I've researched on here, after replacing all fuses and replacing the blown cap on the zsus, I disconnected the zsus switched the set on and no picture or sound, I then disconnected the ysus and reconnected the zsus and still no picture or sound, I do have power at the front panel lights though, and this is as far as I have gone to date.

ps: from the info I've gleaned from forum so far suggest that what I've discovered so far is a common problem with LG boards?

any advice is greatly appreciate, cheers

[PlainBill]

Re: Teac 42" plasma, no picture no sound

Hi all,

This is my first post, well second, I was given a Teac 42" plasma Model PLMSDM1060, which I knew at time of receipt didn't work. The set has power but no picture & no sound.

I pulled the back cover off & checked for anything visually, I replaced all fuses and further inspection found a blown cap #c16 on the zsus board.

Also discovered that this Teac model uses LG panel & boards (shock/horror)

Panel number PDP425V52330, I searched this forum for teac plasma's and didn't find that much info and then search for LG plasma's and found a wealth of information.

My problem is no picture or sound, the info I have gleaned tells me that the easiest fix is to replace the zsus + ysus + upper and lower buffers, however, the age of this model (5 - 6 yrs old) suggest the boards may not be available or if they are, they would be second hand.

part number of the boards (all LG)
zsus - 6870qze009h
ysus - 6870qye007h
top buffer - 6870qde010a
btm buffer - 6870gfe010a

I'm located in australia and have searched OZ ebay without success, US ebay list only a very small handful which are sold as is/used.

As I said above with the age of this model there is good reason to suggest that I may not be able to source the boards, which leaves the option of repairing the boards.

From the LG info I have searched on here (correct me if I'm wrong) seem to suggest that the IC on the boards can be replaced but this is no easy job by any means, what further complicates this is I have virtually no experience in tv or plasma tv's for that, but would love to try and fix this albeit if I could find the boards or repair the boards.

Again from the information I've researched on here, after replacing all fuses and replacing the blown cap on the zsus, I disconnected the zsus switched the set on and no picture or sound, I then disconnected the ysus and reconnected the zsus and still no picture or sound, I do have power at the front panel lights though, and this is as far as I have gone to date.

ps: from the info I've gleaned from forum so far suggest that what I've discovered so far is a common problem with LG boards?

any advice is greatly appreciate, cheers

You are going at the problem from the wrong direction. Also, your troubleshooting logic is wrong.

The second item first: The X, Y, and Z boards AND the main logic board must all be working properly or you won't get anything useful on the screen. Disconnecting any of them and testing to see if you have picture makes as much sense as unscrewing a light bulb, then flipping the switch to see if the light comes on.

Next, the sound and picture are two separate systems that only have two areas in common. Both require a working power supply (picture more than sound); both signals are processed through what I refer to as the small signal board.

My preferred method of troubleshooting this is to hook a signal source to a set of audio and video inputs. This can be a video game to AV1, a DVD player to HDMI 1, it's your choice. Start the signal source, then step through the inputs slowly - it can take a few seconds for the TV to process the inputs. Stop if you hear sound.

If you can successfully obtain sound you know that large parts of the small signal board are working. Leave the signal source hooked up, and see if you see any sign of a picture or light from the screen with all cables connected. Any light on the screen, or a partial picture indicates the Y-Sus and X buffers are working, and the Z-sus is the likely culprit. No light on the screen would indicate either the power supply or the Y-Sus.

If you are unable to hear sound, or if you were, but there is no sign of light from the screen, it's time to check the power supply. On the back of the panel there is a label listing various voltages - Va, Vsc, etc. The corresponding outputs are labeled on the power supply. Check to see if they are correct.

PlainBill

[osci]

Re: Teac 42" plasma, no picture no sound

You are going at the problem from the wrong direction. Also, your troubleshooting logic is wrong.

The second item first: The X, Y, and Z boards AND the main logic board must all be working properly or you won't get anything useful on the screen. Disconnecting any of them and testing to see if you have picture makes as much sense as unscrewing a light bulb, then flipping the switch to see if the light comes on.

Next, the sound and picture are two separate systems that only have two areas in common. Both require a working power supply (picture more than sound); both signals are processed through what I refer to as the small signal board.

My preferred method of troubleshooting this is to hook a signal source to a set of audio and video inputs. This can be a video game to AV1, a DVD player to HDMI 1, it's your choice. Start the signal source, then step through the inputs slowly - it can take a few seconds for the TV to process the inputs. Stop if you hear sound.

If you can successfully obtain sound you know that large parts of the small signal board are working. Leave the signal source hooked up, and see if you see any sign of a picture or light from the screen with all cables connected. Any light on the screen, or a partial picture indicates the Y-Sus and X buffers are working, and the Z-sus is the likely culprit. No light on the screen would indicate either the power supply or the Y-Sus.
If you are unable to hear sound, or if you were, but there is no sign of light from the screen, it's time to check the power supply. On the back of the panel there is a label listing various voltages - Va, Vsc, etc. The corresponding outputs are labeled on the power supply. Check to see if they are correct.

PlainBill

Hi PlainBill,

I followed tour instructions and connected PS2 to video 1 input, turned it on the afer a few seconds turned to the TV on and virtually immediately I could get sound, however, there is no sign at all of any picture or light on/in the screen, I'm guessing this is looking more like a ysus issue? I haven't touched the power supply as yet, simply put, i'm not sure how to measure this as yet being a complete amateur.

Any further advice is greatly appreciated, cheers.

[PlainBill]

Re: Teac 42" plasma, no picture no sound

Hi PlainBill,

I followed tour instructions and connected PS2 to video 1 input, turned it on the afer a few seconds turned to the TV on and virtually immediately I could get sound, however, there is no sign at all of any picture or light on/in the screen, I'm guessing this is looking more like a ysus issue? I haven't touched the power supply as yet, simply put, i'm not sure how to measure this as yet being a complete amateur.

Any further advice is greatly appreciated, cheers.

You are correct, this is PROBABLY a Y-sus problem. I note that the Y-Sus and both buffers are available on eBay for roughly $250. Given the age of this TV, it doesn't make sense to spend that kind of money.

However, note that I said 'probably'. The power supply outputs should be checked before giving up on the set. Doing this is not particularly dangerous IF you are careful not to touch any point that is at high voltage.

I would suggest the following documents to help you. Google the following information, select the link to Scribd, and download each document.

Scribd 7580885

Scribd 13287511

Scribd 19532668

PlainBill

[osci]

Re: Teac 42" plasma, no picture no sound

Thanks heaps Bill...your true gentleman, will do this and report results when I can.

cheers

[osci]

Re: Teac 42" plasma, no picture no sound

Ok update,

I took the Ysus out this morning, apart from virtually every solder joint being & dry cracked, nothing else appeared out of the ordinary.

I carefully checked the IC's on the top & bottom buffer boards with a magnifying glass and no sign of craters or pinholes, I then decided to spend the next 3 hrs re-soldering all the joints, re-fit the Ysus, switched the power on and BINGO I can't believe this....I now have sound & picture. yay for me

But!, there is a dual picture horizontally, there is a horizontal line across the centre of the screen, one picture in the top half, and the same picture in the bottom, the bottom picture is transparent to an extent, I guess I'll have to do some more searching and see what I come up with, but at least its been switched on for nearly 3/4 of an hour and so far no failure.

BTW, is it normal for plasma's to produce as much heat as what the heat sinks appear to be dispersing?


any advice is greatly appreciated, cheers

[osci]

Re: Teac 42" plasma, no picture no sound

I spoke too soon....seems after approx 50 mins 1hr of operation, the same capacitor as mentioned in my first C16 on the Zsus has popped, but still have picture and sound.

[Agent24]

Re: Teac 42" plasma, no picture no sound

I am no expert but my guess would be that the dry joints probably caused something else to fail, which is causing the picture problem and blowing C16...

[Dgtech]

Re: Teac 42" plasma, no picture no sound

Note to OSCI: If you take some clear pictures of the boards in question and post them to this site (dont use 3rd party sites for posting pics), you will have countless senior techs here evaluating your boards. The more eyes that are looking at your problem, the better. Use "Manage Attatchments" on the posting page. Trust me, these guys are good and they want to help you. Help them to help you.

[osci]

Re: Teac 42" plasma, no picture no sound

Thanks DGtech..will try do this over the next couple of days.

[jay17]

Re: Teac 42" plasma, no picture no sound

You are correct, this is PROBABLY a Y-sus problem. I note that the Y-Sus and both buffers are available on eBay for roughly $250. Given the age of this TV, it doesn't make sense to spend that kind of money.

However, note that I said 'probably'. The power supply outputs should be checked before giving up on the set. Doing this is not particularly dangerous IF you are careful not to touch any point that is at high voltage.

I would suggest the following documents to help you. Google the following information, select the link to Scribd, and download each document.

Scribd 7580885

Scribd 13287511

Scribd 19532668

PlainBill

Hi Bill
This is my first time on here
Im after what rating and type is at D-17 on the same y-sus board, has what you are talking about mine has blown and cant find any info .
Would you be able to e-mail me jayson.haworth@yahoo.com

pcb info

MODEL 42V5
BOARD 42V5-YSUS

PART NO 6870QYE007H

LOC NO 2XXX
The component im after is at D-17

[PlainBill]

Re: Teac 42" plasma, no picture no sound

Hi Bill
This is my first time on here
Im after what rating and type is at D-17 on the same y-sus board, has what you are talking about mine has blown and cant find any info .
Would you be able to e-mail me jayson.haworth@yahoo.com

pcb info

MODEL 42V5
BOARD 42V5-YSUS

PART NO 6870QYE007H

LOC NO 2XXX
The component im after is at D-17

I have absolutely no idea.

PlainBill