42" vizio/lg plasma sound no picture

[cadiman]

Yes two at once! I have a plasma, no picture with audio Vizio/ lg I suspect y-sus, but the control board has one led out (d15) There ore 4 led diag lights on this board and can`t find any definition on these. Also on the vizio there is no heat sink on the control board chip ( very warm) and on the lg there is a heat sink. I am thinking y sus and control board? the main heat sink chip is the number one failure on the y sus board, but I don`t have any blown fuses. Power supply voltages are good 180 and 60 also I have all of my low votages on the power supply board. I have not seen a good schematic on this tv. Lots of parts all over for this (a good thing)

[PlainBill]

Re: 42" vizio/lg plasma sound no picture

Yes two at once! I have a plasma, no picture with audio Vizio/ lg I suspect y-sus, but the control board has one led out (d15) There ore 4 led diag lights on this board and can`t find any definition on these. Also on the vizio there is no heat sink on the control board chip ( very warm) and on the lg there is a heat sink. I am thinking y sus and control board? the main heat sink chip is the number one failure on the y sus board, but I don`t have any blown fuses. Power supply voltages are good 180 and 60 also I have all of my low votages on the power supply board. I have not seen a good schematic on this tv. Lots of parts all over for this (a good thing)

Plasma TVs really break down into two subassemblies. One is the plasma panel itself, which included the buffers, sustain boards, control board, and power supply. The second is the small signal board, audio amp and speakers, IR interface, etc.

I suggest identifying the manufacturer of the panel (usually on a sticker on the panel), then identifying other brands using the same panel. Vizio seems to favor LG panels, LG service manuals are fairly easy to find; Vizio not so easy.

Of course, the ultimate resource is Wizard.

PlainBill

[cadiman]

Re: 42" vizio/lg plasma sound no picture

I have found the sme info Wizard has put up on your thread. There are 4 green leds for control board diag and I can`t find a good explenation of the leds. I have the first 3 lit , but the last one is not lit. (d 15) as marked on the board. the service manual does show them with no info. This is an lg board all the way except for the heat sink. I will be putting one on the new board. The manual shows the first picture of the y sus board (1 of 3 ) yours and mine are the first picture for the test point. for the pattern you were looking for. I put my scope on the test port (y buffer board) as you did not want to do. I was not sure where to set ground. I have no picture so I wasn`t expecting much. I think the main chip (heat sinked chip) is smoked I wanted to find a vidio signal going to the y sus board I don`t know where to probe and feel the y sus board my be shorting this out. When I test audio I pull or divide the preamp from the amp to signal trace. I don`t know how or where to do that on a tv. I need to inspect the y buffer board for shorts. I still think my control board is faulty.

[PlainBill]

Re: 42" vizio/lg plasma sound no picture

I have found the sme info Wizard has put up on your thread. There are 4 green leds for control board diag and I can`t find a good explenation of the leds. I have the first 3 lit , but the last one is not lit. (d 15) as marked on the board. the service manual does show them with no info. This is an lg board all the way except for the heat sink. I will be putting one on the new board. The manual shows the first picture of the y sus board (1 of 3 ) yours and mine are the first picture for the test point. for the pattern you were looking for. I put my scope on the test port (y buffer board) as you did not want to do. I was not sure where to set ground. I have no picture so I wasn`t expecting much. I think the main chip (heat sinked chip) is smoked I wanted to find a vidio signal going to the y sus board I don`t know where to probe and feel the y sus board my be shorting this out. When I test audio I pull or divide the preamp from the amp to signal trace. I don`t know how or where to do that on a tv. I need to inspect the y buffer board for shorts. I still think my control board is faulty.

First step: What is the panel number (white label just to the left of the power supply when viewed from the back of the set)? Mine is PDP42X30201

It is also possible to get a lot of information on this by searching eBay for the model number of the TV. That should bring up hits for the common cards.

One potential source of confusion: Depending on who is writing the description, there are two (main) / (control) boards in these sets. There is the main TV board (Philips calls it the Small Signal Board; LG seems to call it the CI_PDP Block.) There is also the panel control board. The sets I am working on have that buried behind the main TV board. I couldn't even see any LEDs on it.

As it currently stands, I have determined the problem on both sets is the Z-sus board. One is currently working, the board for the other is on order.

PlainBill

[Wizard]

Re: 42" vizio/lg plasma sound no picture

These LEDs only serve to tell you they are doing something (alive and running either flashing or lit). Not for diagnostic info.


Cheers, Wizard

[cadiman]

Re: 42" vizio/lg plasma sound no picture

This board is called the control board (lg) and yes I agree these leds tell you whats on and or working. If they are not lit up that would be a diag for me. I think they should be lit? just a guess. This is a vizio made by lg (pdp42x32000) This board is behind the vidio input /tuner board. I did find the same info on line that you had put up on here.
I will do some more probing soon. Trying to cook dinner and chase a set of twins around while doing this.

[PlainBill]

Re: 42" vizio/lg plasma sound no picture

This board is called the control board (lg) and yes I agree these leds tell you whats on and or working. If they are not lit up that would be a diag for me. I think they should be lit? just a guess. This is a vizio made by lg (pdp42x32000) This board is behind the vidio input /tuner board. I did find the same info on line that you had put up on here.
I will do some more probing soon. Trying to cook dinner and chase a set of twins around while doing this.

OK, that seems to be the same panel used in the two TVs I'm working on. I'm going to try to get waveforms with both good and bad Z-Sus cards. That may help you.

One additional piece of information on my sets. The signal at the test point marked 'Waveform' made obvious changes as the picture changed. Based on my experience, if you are seeing signal changes at that test point the panel control card is probably good.

I just peered at the control card and was able to see the leds you mentioned. All four of them seem to be on without any flickering.

PlainBill

[cadiman]

Re: 42" vizio/lg plasma sound no picture

Thank you, I am missing d15 (not lit) this is the lowest led on the led tree. I need to check for vidio signal going in and check for proper signals going out to y sus board. Should thses be the timming waveforms that control y and z boards? Keep looking at the control board to the left of the leds there is the main chip, as I said before the vizio has no heat sink, but the lg does. (mine gets very warm almost hot). I just put the kids to bed so I am going to put this thing back together and hunt some waveforms. Did you take your scope pictures with the lights off? I will have to find my adapters for my probes for this to work.

[cadiman]

Re: 42" vizio/lg plasma sound no picture

There is one thing I wanted to talk about. I do have parts of my haitachi/pioneer plasma service manual and when doing diag on the power supply they tell you to remove y plug and restart power supply and see if it shuts down if not then unplug the x drive and repower and check for shut down. I have never had a problem doing this as long as I had the power off when plugging or unplugging boards. I don`t think I would do this with the driver/buffer boards.

[PlainBill]

Re: 42" vizio/lg plasma sound no picture

There is one thing I wanted to talk about. I do have parts of my haitachi/pioneer plasma service manual and when doing diag on the power supply they tell you to remove y plug and restart power supply and see if it shuts down if not then unplug the x drive and repower and check for shut down. I have never had a problem doing this as long as I had the power off when plugging or unplugging boards. I don`t think I would do this with the driver/buffer boards.

That is also mentioned in one of the LG training manual. This is what I gather: In some circumstances a failure of the Y-Sus or Z-Sus will overload the power supply, which will go into protect mode (shut down and not restart until power has been unplugged for several minutes).

The recommended test procedure in case of the power supply going into protect mode is to unplug each of the loads on the Vs and Va supplies, testing after each load is unplugged. I don't remember the order, but if the power supply goes into protect mode even with the Y-Sus unplugged, but doesn't if the Y-sus and Z-sus are unplugged, the culprit is presumed to be the Z-sus card. Of course, power should be OFF before unplugging any cable.

I agree, this goes against the usual rules for treatment of electronic equipment. I did try this with my first LG HDTV (the one with the bad power supply). Alas, it was the power supply.

PlainBill

[cadiman]

Re: 42" vizio/lg plasma sound no picture

Where is the best place to buy these boards? New or reman? I see alot on ebay some used and some reman. Also, I think the y and z modules are available for replacement. I wanted to fix the tv first then look at board repair. This is how I learned delco radios inside and out. It really helps to have two with one working. If only one alien spaceship crash landed here we would not be this far ahead in electronics. I am sure there were two. we couldn`t find service training manuals for those either!

[PlainBill]

Re: 42" vizio/lg plasma sound no picture

Where is the best place to buy these boards? New or reman? I see alot on ebay some used and some reman. Also, I think the y and z modules are available for replacement. I wanted to fix the tv first then look at board repair. This is how I learned delco radios inside and out. It really helps to have two with one working. If only one alien spaceship crash landed here we would not be this far ahead in electronics. I am sure there were two. we couldn`t find service training manuals for those either!

I usually start by looking on eBay, and looking at the price, source, and reputation of the seller. I'd prefer to buy a new board over a repaired or rebuilt board, and will take a repaired board over a 'used but tested good' board. Of course, I wouldn't touch a 'untested but I think it's good' board.

PlainBill

[cadiman]

Re: 42" vizio/lg plasma sound no picture

Thanks, again! I have found all the boards on ebay. I should have something put together and running by the end of April. Looking forward to some scope patterns.

Cadiman

[PlainBill]

Re: 42" vizio/lg plasma sound no picture

Thanks, again! I have found all the boards on ebay. I should have something put together and running by the end of April. Looking forward to some scope patterns.

Cadiman

Well, here are some scans that show good and bad Z-sus cards. There are a number of orange 'hooks' (actually a loop of wire with a ferrite bead) near the output connectors. These were taken at B28, which is by itself, just above P5, the lower connector. In both cases, the signal was the opening sequence to 'The Lion King', but there was no visible change to the waveform as the video changed. I can't speak for other failure, but this one seems very clear-cut.

If possible, I will try to get waveforms on the input from the control card and the output to the Z-sus before buttoning this up. The chance of getting something similar on the input to the Y-Sus is remote, since I'd have to pull the main TV panel to get to the connector.

PlainBill

[cadiman]

Re: 42" vizio/lg plasma sound no picture

The 2nd waveform is similar to my y sus output. This looks like heat sinked ipm failure? I am waiting on a y sus board to see if light comes on (d15) and should get a picture. Back in my younger days I could spend days logging scope waveforms. It is really hard getting waveforms from the control board. I hope to pick them up on the y sus board. I don`t know if ipm bad brings down the input signals from control board. On amplifiers I would remove the mosfets or outputs and scope to confirm waveform input. I would look in my ecg book to fine the ic and get all of my specs. I really miss that here.

[PlainBill]

Re: 42" vizio/lg plasma sound no picture

The 2nd waveform is similar to my y sus output. This looks like heat sinked ipm failure? I am waiting on a y sus board to see if light comes on (d15) and should get a picture. Back in my younger days I could spend days logging scope waveforms. It is really hard getting waveforms from the control board. I hope to pick them up on the y sus board. I don`t know if ipm bad brings down the input signals from control board. On amplifiers I would remove the mosfets or outputs and scope to confirm waveform input. I would look in my ecg book to fine the ic and get all of my specs. I really miss that here.

Well, I've got sorta good news. I spent too many hours hunched over the tv, but I've managed to photograph all the drive waveforms from the control card to the Y-sus and Z-sus cards. I've made good notes, but I'm going to Disneyland with my Grandkids this weekend and I probably won't get a chance to put them up until Monday.

PlainBill

[cadiman]

Re: 42" vizio/lg plasma sound no picture

Have fun! Don`t hurry, I won`t get the parts till next week. I have a few golfcarts here for rebuilds. I can tell spring is here just by the phone calls. Tvs may be on the back burner.

[cadiman]

Re: 42" vizio/lg plasma sound no picture

Wow! I just removed the main chip on the y sus board. K F C what`s cookin. I`ll have a new one in a few days.

[cadiman]

Re: 42" vizio/lg plasma sound no picture

This thing has a pretty good picture. I still need to set waveform. I set all the voltages. I have some speckles in the picture and tweaked the voltages one at a time and helped to correct a bit. I think the waveform adjustment will solve this. If not it`s not that bad only notice on black screen. I am new to plasma, but these boards (y and z) need some cooling help. The y-sus runs too hot. I think I will be installing some cooling fans before I button this thing up. The power supply runs cool. The stk chip I replaced was much better looking than the old one (looked cheap).
Thanks for all the help everyone, Cadiman

[PlainBill]

Re: 42" vizio/lg plasma sound no picture

This thing has a pretty good picture. I still need to set waveform. I set all the voltages. I have some speckles in the picture and tweaked the voltages one at a time and helped to correct a bit. I think the waveform adjustment will solve this. If not it`s not that bad only notice on black screen. I am new to plasma, but these boards (y and z) need some cooling help. The y-sus runs too hot. I think I will be installing some cooling fans before I button this thing up. The power supply runs cool. The stk chip I replaced was much better looking than the old one (looked cheap).
Thanks for all the help everyone, Cadiman

In one of the other threads it was mentioned that the 15 volt supply for the hybrid is generated on the card. A low 15 volt supply has been associated with failure of the hybrid (maybe overheating?).

PlainBill