LCD TV screen goes White when power off

[cmccul002]

Westinghouse 19" LCD TV. Everything is fine until I turn the TV off. When I power off the TV the screen goes bright white.

To get it to go all the way off, I have to unplug it.

Thanks.

[PlainBill]

Re: LCD TV screen goes White when power off

Westinghouse 19" LCD TV. Everything is fine until I turn the TV off. When I power off the TV the screen goes bright white.

To get it to go all the way off, I have to unplug it.

Thanks.

It's either the control signal to the inverter, or a bad transistor on the inverter. What happens when you plug it it, but don't turn the TV on?

PlainBill

[cmccul002]

Re: LCD TV screen goes White when power off

When i turn it off, it starts as a dull white screen, and slowly gets brighter.

Nothing happens when I plug it back in. It just stays off, unless i turn it on and then its fine.

[PlainBill]

Re: LCD TV screen goes White when power off

When i turn it off, it starts as a dull white screen, and slowly gets brighter.

Nothing happens when I plug it back in. It just stays off, unless i turn it on and then its fine.

That would indicate it's probably a problem on the main board. The output controlling the inverter never switches it off. The behavior of the display is normal for an LCD panel with no power, but active backlights.

PlainBill

[cmccul002]

Re: LCD TV screen goes White when power off

That would indicate it's probably a problem on the main board. The output controlling the inverter never switches it off. The behavior of the display is normal for an LCD panel with no power, but active backlights.

PlainBill

Nice. Would that be any kind of fix for a non-pro?

[PlainBill]

Re: LCD TV screen goes White when power off

Nice. Would that be any kind of fix for a non-pro?

I would say no. I've got a similar TV (Memorex) that consists of three boards (main, tuner, and inverter. About all you could do is check the control line from the main board to the inverter. If the line doesn't change level (0 to 5V or 5V to 0) the problem is on the main board. A schematic would be necessary, but probably would show that this is a direct output of the main IC (probably a 200 pin monster). In MY opinion (others may disagree) the only practical solutions would be to replace the main board with a new one, or replace the main board with one from a TV that was dropped.

The situation you and I face is that these sets were turned out by the cargo container full in China with Memorex, Westinghouse, Magnavox, Polaroid, Skyworth, Coby, etc name plates. They were sold by Wal-Mart; K-Mart, Circuit City, Best Buy, Kroger, Piggly Wiggly, etc. In most cases the warranty plan was simple. A certain number of sets were held back as a reserve. If a set failed under warranty the customer would ship it back to a warehouse in California at his expense, the warehouse would ship a replacement back to the customer at his expense. Initially these came from the reserve. In the warehouse some 'Technician' would test each set. If it worked it went back in the box as a reserve. If it didn't work it was set aside. When the warranty period expired any sets remaining in the reserve were shipped off to places like Big Lots, or a shopping channel. If they ran through the reserve they would attempt to sort by type of failure, then swap boards to repair some of the easy ones.

The problem is it isn't cost effective to have someone of Wizard's ability troubleshooting and repairing them so a set that retailed for $250 can be replaced. Therefore no more than a cursory effort was made to provide schematics or service manuals, or provide spare parts.

For a look at the bleak picture, see this column.

PlainBill

[Wizard]

Re: LCD TV screen goes White when power off

How can I find the names of makers for first, second and third tier groups?

I'm taking names so I can know them better.

Cheers, Wizard

[cmccul002]

Re: LCD TV screen goes White when power off

Wow, pretty informative. Thanks again PB.

[Krankshaft]

Re: LCD TV screen goes White when power off

Interesting article.

I'm glad I was right when I had a fishy feeling about those off color unknown brands.

I honestly always go for the name brands especially since I always seem to need the service manuals depending on how complex the failure is.

Based on what I read there good luck on getting ANY servicing info you can't even get parts for those Chinamart brands. Fleabay would be your only hope and that just gives me the shivers.

Hey Visio I got a revision for your slogan:

Visio Where Vision Meets The Dumpster

[PlainBill]

Re: LCD TV screen goes White when power off

How can I find the names of makers for first, second and third tier groups?

I'm taking names so I can know them better.

Cheers, Wizard

Shucks, I was hoping YOU would know them. I'm not sure of that writer's criteria for distinguishing between 1st, 2nd, and 3rd. I guess I'd use the availability of parts and service as one guide.

If Joe Nobody can order a service manual and replacement parts for something built 4 years ago, it's definitely 1st tier. If service, manuals, or parts aren't available after the 3 month warranty expires AND their name is one of the brands that 'Used to be a household name', it's definitely 3rd tier.

One thing that bears remembering. IMHO, the HDTV / LCD industry is in about the same level of maturity that TVs were in the 1950's. It wasn't a question of 'Is something going to go wrong?', it's 'When will something go wrong?' In 1997 my sons gave me a 32" Sony color TV. It worked perfectly for 6 years, then about 3 months after moving cross-country the vertical sweep became unstable. I opened it up, resoldered the bad solder joints on the vertical deflection IC, touched up the focus, and it's still working. I just picked up a new 19" Sony Bravia today. I figure I'll be doing darn well to get three years out of it without troubles. But I will have an advantage - With Sony getting involved in servicing these, the chances are they WILL learn what fails and apply the lessons to the newer products.

PlainBill

[fzabkar]

Re: LCD TV screen goes White when power off

To give you an idea exactly what parts are available for your TV, go here:

http://bestbuy.partsearch.com/ModelS...&ModelNumber=+

:-(

If you can upload some internal photos, then perhaps someone will recognise the actual manufacturer of the set.

I suspect that this problem would be an easy fix for a moderately experienced tech, assuming that the on/off signal to the inverter is not going bad at the main IC.

A Westinghouse model number would also be a big help ...

[fzabkar]

Re: LCD TV screen goes White when power off

Another way to determine the real manufacturer may be to obtain a V-Chip firmware update and then scan the file for text strings.

http://www.wde.com/vchip/

Still another way may be to hook it up to your PC and scan the registry for EDID information.

[tmwalsh]

Re: LCD TV screen goes White when power off

The race to the bottom has begun in REAL earnest. May the winner love all the mercury, chromium and cadmium they find.

Back to the OT, if you disassemble the TV by removing the base cover and splitting the front and back halves, you may be able to trace back from the inverter to the control board. Generally, there are few things coming to the inverter. Ground, power, 'brightness level', and on/off signal. If the board is labeled in a language you understand, you may be able to trace back on the control board and find a standalone transistor used to provide the on/off signal. If you are lucky...
Sometimes the board may have a part number that you can google, and find the actual manufacturer. Sometimes this does no good as they want to sell in quantity 100. ... minimum. or 40 foot shipping container.
Anyway, if you can find the switch trace you may be able to repair your set. You could always put an in-line rocker switch to the A/C supply.

We are getting into a ridiculous situation where nothing is repairable. One would think that the energy used to create these [mumble mumble] sets would end up being more expensive than providing the minimum of support.
I want there to be the requirement that all electronics come with schematics. When I bought in the Navy Exchange, most electronics came with a schematic. Even the TEAC cassette tape recorder had a schematic. We are talking cents to produce these. Wally World could make that a requirement of their suppliers at no cost to them self, and make a lot of friends in the process.
Whatever.


tom