Vizio 42" Plasma - Bad Caps in Y and Z Sus

[aliasdck]

Got a 42" Vizio Plasma TV. Original Owner says there was a loud pop and then the screen went dark. Simple searching around has shown this a common problem. Recommendation is to replace y-sus, z-sus and control board at the same time... thats not gonna happen on my budget. I'm not fixing this TV for anybody nor am I fixing it to resale it... this is simply for fun

Anyways, I opened her up and found that there was a swollen cap on both the y sus and z sus boards. The the cap on the y sus board is swollen badly... the pictures I've included don't really do it justice as I took them from the wrong angle.

The main fuse on the y sus board is open (it fuses the incoming Vs that is fed from the power supply). A continuity test shows there is a direct short between Vs and Ground... I checked all the major components (besides the IPM) and cannot find where the short is, but I suspect its the IPM module. I'm just waiting for an order of chip quick to arrive so I can remove it for a better look/test.

I'm also getting a esr meter in a few days as well... I want to check the various caps throughout the TV as they are mostly samwha's circa 2004.

Nothing appears wrong with the z-sus board except that one of the same types of cap is swelling on the top as well. Vs input fuse is still good and no short from Vs to ground as there is on the y-sus. Hopefully there is nothing wrong with the z sus board aside from the swollen cap.

Swollen caps are Samwha HK 250V 680uF

Pictures are of the y sus board. The swollen samwha is in parallel with another identical cap. These caps are installed across Vs and ground.

[Wizard]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

Don't bother with caps. This is board swap only if the fuse popped because of poor design internal to the hybrid IC under that flat big heatsink, this is Y drive board by the way. If price of a new y drive board or good one scare you, dump plasma tv. They were poor investment to fix. especially ones that uses hybrid IC on the Y drive board or X drive board.

Reason for this failure is internal solder break on the small ceramic hybrid module that is connected to another larger hybrid ceramic board.

Later plasma TVs went with MOSFETs instead of hybrid ICs. Far more repairable.

Cheers, Wizard

[hardwareguy]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

Remove heatsink....see if its an industry standard IC. If so, fix that and then fix all the other damage.

If not, swap the board and fix the rest if you feel its worth it.

[Krankshaft]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

Is that IC heatsink bonded with thermal epoxy?

Vizio TVs are disposable sets I wouldn't even bother picking one off the curb honestly.

Name brand sets only since they have easy to purchase parts (through parts distributors like Encompass) and service manuals.

When repairing something you have to draw a line if you replace the board and as Wizard said the IC design is prone to failure. You're only postponing the time to another failure. Then the set is not worth fixing.

It's only worth repairing if the design has been improved on to reduce the chance of another failure.

[aliasdck]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

This is the part under the large flat heatsink... is this what you guys are referring to as "hybrid IC"?

http://cgi.ebay.com/NEW-YPPD-J001A-Y...16231008r19782

If I understand you guys correctly, you are saying even if I replace this IC and the caps (and any other failed components) its very likely the set will fail again shortly?

If so then this tv really is a disposable POS. Thankfully I haven't invested anything but a few minutes into repairing it thus far.

Wizard... you say this board is the y driver board, but I thought this board was the y sustain board (it is even labelled as y-sus) I thought the y driver board was the long skinny board on the left of the set (from rear view) with multiple ribbon cables connected directly into the panel.

One more thing: I see there are online stores out there selling "repair kits" for plasmas with LG panels such as this one. The kits contain new y-sus, z-sus and control boards. Have these boards been redesigned in some way?

Thanks for the tips guys, sounds like you may be saving me a lot of time and fustration.

[hardwareguy]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

Its doubtful that the replacement board kits have been revised. It would be a MAJOR selling point if they were.

[Wizard]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

Yes that is hybrid IC. Newer design. Difficult job due to very heavy power planes in the circuit when desoldering. The heatsinks is screwed to the IC before installation and soldered.

No. It is certainly not disposeable unit. Anyone can buy name brand panels (they already come with their boards except the mainboard that generic maker designed and supplies the brackets, casing and mainboard to make their own TV.

The panel is Samsung by the way and all the boards that is for panel (Y SUS, X SUS, and Z buffers, two boards are Samsung's for that particular panel. Power supply and mainboard usually other sources or custom designed.

Cheers, Wizard

[aliasdck]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

I appreciate the advice greatly guys

I think Im going to give this a shot... the caps and the hybrid IC are going to cost me roughly $70... which Im willing to loose worst case. Mostly I'm in this for the learning experience and also for the fun of it.

My order of quick chip should arrive tomorrow and with some creative heating I should hopefully be able to remove the hybrid IC (which is what I have been referring to as the IPM).

[PlainBill]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

I appreciate the advice greatly guys

I think Im going to give this a shot... the caps and the hybrid IC are going to cost me roughly $70... which Im willing to loose worst case. Mostly I'm in this for the learning experience and also for the fun of it.

My order of quick chip should arrive tomorrow and with some creative heating I should hopefully be able to remove the hybrid IC (which is what I have been referring to as the IPM).

That's Chip-Quik. A 'quick chip' is the one that fails because I did a sloppy job of soldering it in.

PlainBill

[Krankshaft]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

This is why I'm not an early adopter of new technology. Let the other guys who need to be on the cutting edge dump their hard earned money and get screwed with all the problems. Until they're worked out by the manufacturers.

Wizard what kind of wattage iron you thinking to get the IC off?

Since the OP didn't specify what kind of equipment.

[aliasdck]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

That's Chip-Quik. A 'quick chip' is the one that fails because I did a sloppy job of soldering it in.

PlainBill

Wizard what kind of wattage iron you thinking to get the IC off?

Since the OP didn't specify what kind of equipment.

That would be helpful (along with any other removal advice if anyone has any) as this doesn't seem as if its going to be easy. I didn't mention what kind of equipment because I don't know what I'm going to use... gonna play it by ear I suppose.

[aliasdck]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

IC Removal went fairly well... managed to do it without doing any damage to the pcb. I did this by adding a little Chip Quick onto each pin. My 60 Watt soldering iron was hot enough for most of the pins, but (as wizard mentioned) I could not get the connections that were heavily bused together hot enough (Vs, Ysus and ground connections). So I used two soldering irons at the same time to heat these connections while an assistant applied the chip quick.

Then I preheated the entire board in the oven at 150 F for 10 minutes, pulled it out and applied heat via a heat gun to get the solder/chip quick to melt. I was unable to get all the pins hot enough simultaneously in order to pull the ic out, so I worked in quadrants... heating the corners of the ic while gently pulling the ic out. Took only about 5 minutes of gently persuasion to get it out.

IC has definetly failed. Two of the transistors (IGBTs?) have popped.

Installed the new IC (Which required the use of two soldering irons again guess I need a hotter iron) and replaced the 4 caps previously mentioned on both the y-sus and z-sus.

TV works now BUT while looking around the internet elsewhere I've seen it recommended to check the 15 Volt supply on the Y-sus board because the likely cause of failure of the IC in the first place was an unstable 15V supply.

And whaddya know, the 15V supply was rising and falling between 10.9 and 12.4 V. Traced the 15V to where its generated on the y-sus board and found that a couple of small smd capacitors have failed there.

Caps are on order now.

[Wizard]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

Awesome!!

Cheers, Wizard

[aliasdck]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

Good news and bad news:

The good news is I replaced the caps around the 15V supply and now it is running at a steady 14.5V.

The bad news is I watched the TV for a few minutes and noticed that after a couple of minutes the display begins to develop sparkles... mostly green but sometimes blue and sometimes red sparkles blinking around the display. Looks like pixels are misfiring randomly.

Did quite a bit of research on this and it appears to be very common with these sets. There are a few recommendations on how to try and fix this.

1) Lower Vs about 5 to 10V (I tried this but it had zero effect)
2) Adjust Setup and Setdn on Y-sus board - haven't tried this yet as I don't have access to a 200Mhz scope (as recommeneded by the service manual).
4) Replace Y-sus, Z-sus and control board (and possibly y and x driver boards) at the same time
3) Replace panel... some suggest the panel has aged and its time to dispose of it and get a new TV.

I haven't given up yet. I did some more checking around the Y-sus and Z-sus boards today. I discovered two anomalies and was hoping to get some feedback if anyone had any:

1) The sticker on the panel lists all the power supply voltages. I checked all of them and they all check out excellent except for the Vsetup voltage which should be 210V. I get a reading of 208V and sometimes it drops down to 205 V briefly and sometimes it bounces up to about 213V briefly. This seems odd to me... I don't know if its the cause of the problem or a symptom of the problem

I checked the esr of the caps in the circuit that generates the Vsetup voltage and everything seems sort of okay. ESR on a couple of the caps is high... around 3 ohms, but its for the caps rated for 350V so I expect the esr to be high (datasheets dont list esr for these particular caps, only ripple current). There are identical caps elsewhere in the tv all with similar esr so I dont think this is the problem.

2)I found one surface mount capacitor with questionable esr on the z-sus board. Its right around the ramp_up IC and potentiometerr. ESR is reading 2.1 Ohms while identical caps on the board are all less than 0.1 Ohms. I'll replace it tomorrow and see what happens but at this point my hopes aren't high.

Any thoughts?

[Wizard]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

Sparkling needs slightly adjusting on Vs and Va on the power supply ONLY. If one did not fix that, return to original and try other. It only take a little. Must have panel warmed up 1/2 hour to a hour first and running while adjusting.

Do NOT adjust anything ELSE. These other adjustments on the other boards *requires scope* to do it. This is why I do not *like* leaving newbies with plasma panels.

Cheers, Wizard

[aliasdck]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

I have no intention of adjusting anything else... as I said, I don't have a good enough scope so I'm not going to bother.

And just to clarify, I'm not a newbie to electronics (but I am a newbie to TV repair). I have been involved with electronics for 10 years and have worked as a technician doing component level repair for 5. Unfortunetly I am unemployed at the moment so I do not have access to my usual test equipment - a decent scope being one of them.

I'll give Va and Vs adjustment as you specified and report back. Fingers crossed.

Thanks.

[aliasdck]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

Adjusting Va didn't do anything to improve the picture so I set it back to where it was. Slightly adjusting Vs higher improved the picture dramatically (going lower did nothing)... there were still a few sparkles but they were nearly impossible to detect unless you stared at the TV from a few inches away.

[Wizard]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

Then adjust Vs more higher if not adjust the Va bit more either way. It interacts, getting you closer and closer to ideal.

You are doing right thing.

Cheers, Wizard

[balut]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

I have the same problem with my Vizio 42" Plasma. POP of Death, no picture, sound ok. The tech replaced the Big Chip with nig Heatsink on the Y-SUS board.
Tv works ok for about 10 minutes, then develops sparklies, then colors start getting crazy. I checked the heatsink on the Y-sus board and is very hot.

Switched off the Tv , let cool down then switch on again. picture ok, but same thing after 10 minutes sparkies and colors go crazy.

what could be the other problem on this ? is there something else bad on the Y-sus baord ? How do you check the VSetup voltage, where do you monitor the voltage ? I want to try adjustong the VSetup voltage to see if it fixes it.

I am more concerned with the abnormal heating of the heatsink after 10 minutes. could it be bad capacitors ?

[PlainBill]

Re: Vizio 42" Plasma - Bad Caps in Y and Z Sus

I have the same problem with my Vizio 42" Plasma. POP of Death, no picture, sound ok. The tech replaced the Big Chip with nig Heatsink on the Y-SUS board.
Tv works ok for about 10 minutes, then develops sparklies, then colors start getting crazy. I checked the heatsink on the Y-sus board and is very hot.

Switched off the Tv , let cool down then switch on again. picture ok, but same thing after 10 minutes sparkies and colors go crazy.

what could be the other problem on this ? is there something else bad on the Y-sus baord ? How do you check the VSetup voltage, where do you monitor the voltage ? I want to try adjustong the VSetup voltage to see if it fixes it.

I am more concerned with the abnormal heating of the heatsink after 10 minutes. could it be bad capacitors ?

It could be. Or it could be a case that the voltages on the Y-sus were not adjusted correctly. Or there could be a bad buffer IC. I'd suggest researching the clues aliasdck gave us and checking the 15V supply, which is on the Y-Sus board.

PlainBill