I need your guy's help. need any technical info available for Viewpia LCD TV's - Page 2 - Videokarma.org TV - Video

andy · #16 10-29-2009, 05:42 PM

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MRX37 · #17 10-29-2009, 05:48 PM

Quote:

Originally Posted by RobtWB

Just reviewed the entire thread.

You state -

Country of origin - China
Sets fail within a week
Hundreds of sets affected

OK - I'll be a smart a** - why bother with them???

No choice in the matter. I won't get into why that is, but we're stuck with the damn things and we have to sell em.

I know they're crap. There's nothing i can do about it except try to track down the causes of failure.

MRX37 · #18 10-29-2009, 05:49 PM

Quote:

Originally Posted by mbates14

ive seen that exact controller IC used in numerous other LCD sets that I have worked on. its even heatsinked. the failure rate of that CPU control IC is low... so low that it isnt evne possible, however the vizios use the same IC and they DONT have a heatsink, but i find them failing an alarming rate becuase of lack of a heatsink, proper heatsinking problem never shows up.

In your case, i would vote out the main IC. what you need to do is monitor the on-board boost/buck switching regulators that pump out the proper core voltages for shorts and/or proper voltages. standby light is probably dim because there is a short in the rail on that main control module. ive delt with a couple of other brands with similar issues, and it turned out to be core regulator output transistors had failed.

keep an eye on these. And im also sure it goes without saying, in standby mode, check for excessive heating of any transistor, and obviously the CPU core. if the CPu gets abnormally hot then your done, only solution is to replace the board unless you can find a supplier in china for the IC, and usually these ICs have custom programming stored on the IC itself so your chances for that are none... And check your class-D audio output circuits for rail loading.

Glad I can rule out the IC.

We had one TV work intermittently. It displayed this same symptom, then fixed itself, then died again.

Could you perhaps point out the transistors you are talking about?

MRX37 · #19 10-30-2009, 06:41 AM

Okay, so the plan now is to check for shorted transistors.

Any luck on getting any technical info, like, oh how to access the service menu on these things?

See, the idiots who programmed these, most are all right, but about 10% of them either have the color set way too high, or the LED backlight set too low, or some other screw up that might require a firmware update (as if I could get ahold of that), but may be fixable in the service menu... if I could access the damn service menu...

andy · #20 10-30-2009, 11:02 AM

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MRX37 · #21 10-30-2009, 12:07 PM

Quote:

Originally Posted by andy

If it's intermittent, then I'd just about bet my life on bad soldering. Shorted transistors, and blown ICs don't fix them selves. It could also be a firmware bug that's causing problems (eg. corrupted NVRAM locking up the micro controller). I fixed one LCD TV with badly distorted video by reprogramming the settings EEPROM from the one in a good set.

Bad soldering was my first guess, but I've looked all over for bad soldering, and touched up numerous solder connections that were fine to begin with. It's not a huge board, but there are so many solder connections... and bad soldering would lead to a host of other issues. Apart from this one issue, these TV's have nothing else wrong with them, apart from the occasional TV with programming issues.

The TV's that work, work just fine. We have two being used here as computer monitors. They're left on all day long. We've been using them for a couple months with no issues. It seems that if one of these TV's can make it past 2 or 3 weeks, then the chances of it failing drop drastically.

These TV's are all failing in the same way. This tells me that the failure is occurring in the same area, and maybe the same component or solder connection. Only one TV so far displayed this intermittent behavior, out of maybe 15-20 that have just outright failed without any warning whatsoever.

MRX37 · #22 10-30-2009, 12:17 PM

By the way: If it will help, here is a high resolution picture of one of the dead chassis boards.

crtfool · #23 10-30-2009, 04:31 PM

Is that a burn mark on the 8 pin IC just above the VGA connector?

mbates14 · #24 10-30-2009, 04:48 PM

if its intermittent, ill tell you what the problem is. soldering. period.... no matter what.

easiest way to resolder a flat-pack IC such as the micro, is take a thing of solder paste, the stuff you refrigerate, use a needle tip, put a tiny bead on all 4 sets of pins. then take a hot air rework station, about 25% air, 75% heat adjustment, and then take the smallest gun tip you have, like i do, and gradually blow toward and go down the set of pins. it will re-do solder on all pins, using a lighted magnafier, wick up any potential cross-over.

if you are going to repair any of these kinds of electronics, you must have a rework station, thats about the jest of it. and by looking at your high-res photo, i can see some cracking of the pins of the CPU because of the heat issue. plus its not a bad idea to reflow the DRAM IC.

MRX37 · #25 10-30-2009, 05:51 PM

Quote:

Originally Posted by crtfool

Is that a burn mark on the 8 pin IC just above the VGA connector?

No. It's marker or paint of some type.

MRX37 · #26 10-30-2009, 05:52 PM

Quote:

Originally Posted by mbates14

if its intermittent, ill tell you what the problem is. soldering. period.... no matter what.

easiest way to resolder a flat-pack IC such as the micro, is take a thing of solder paste, the stuff you refrigerate, use a needle tip, put a tiny bead on all 4 sets of pins. then take a hot air rework station, about 25% air, 75% heat adjustment, and then take the smallest gun tip you have, like i do, and gradually blow toward and go down the set of pins. it will re-do solder on all pins, using a lighted magnafier, wick up any potential cross-over.

if you are going to repair any of these kinds of electronics, you must have a rework station, thats about the jest of it. and by looking at your high-res photo, i can see some cracking of the pins of the CPU because of the heat issue. plus its not a bad idea to reflow the DRAM IC.

I have a soldering iron. That's it.

Also, it was intermittent on *one* tv... out of maybe 20 that have failed so far.

mbates14 · #27 10-30-2009, 06:15 PM

Quote:

Originally Posted by MRX37

I have a soldering iron. That's it.

Also, it was intermittent on *one* tv... out of maybe 20 that have failed so far.

i understand that. but what i said still holds true.

MRX37 · #28 10-30-2009, 08:52 PM

Quote:

Originally Posted by mbates14

i understand that. but what i said still holds true.

Okay. The heatsinked chip is a suspect for bad connections then?

The EURAS database has info on Viewpia models, and probably has the info I need, but I can't access the damn thing.

mbates14 · #29 10-30-2009, 09:03 PM

EURAS is free for like 30 days, well it used to be, also try here: [email protected] discussion

MRX37 · #30 10-31-2009, 07:14 AM

Quote:

Originally Posted by mbates14

EURAS is free for like 30 days, well it used to be, also try here: [email protected] discussion

You need to be a registered repair company and have all kinds of certifications and blah blah blah.

But I'll check out your other link. Thanks.