19 polaroid tla-01911c

[BADHIGEEN]

Hello every one its been awile since my last post https://www.badcaps.net/forum/showth...light=polaroid
and I am very pleased to say my polaroid 40 inch is still working like new so when my 19 inch polaroid in the garage crapped out I was sure of the problem but when I opened it up to get at the power supply board I could not find any obvious bad caps. I was hoping mabey some of you might point ot the culprets so please feel free. I can supply more pics if needed.

[sofTest]

Re: 19 polaroid tla-01911c

I can't tell from the pictures, but if you use your fingertip, does any of the caps feel even slightly bulged?

[BADHIGEEN]

Re: 19 polaroid tla-01911c

They all look ok to me. My 40 inch tv was easy you could see very well wich ones were bad. I will post some better pics.

[BADHIGEEN]

Re: 19 polaroid tla-01911c

here are a few more close ups of the board and caps

[sofTest]

Re: 19 polaroid tla-01911c

From the last of the pictures, of the pair of blue HECs in the background in the first picture, the left one might be a candidate. In R.W., do they look and feel identical? Most of the other caps are still to blurry to tell. And it's not always possible to visibly tell if a cap is bad. All of the caps seems to be from the list of bad manufacturers, so you might want to replace them all anyway.

Have you looked for any other problem on the boards? Anything looking burned?

[BADHIGEEN]

Re: 19 polaroid tla-01911c

The board and comps are clean no burns no dust. The tv was made in 07 just a year old I bought 1 for me and 1 for Mom from walmart. Moms runs all the time mine was hooked up in the garage to a pc and rarley got used and no power I turn the breaker off when I am done out there. I think you are right and I will make a parts list to post here for opions on what to get. If I can fix mine and Moms craps out it will be a piece of cake the second time around

[PCBONEZ]

Re: 19 polaroid tla-01911c

BADHIGEEN
Did you ever resolve this?
I just opened up an Element FLX-2210 with the same problem.
Element 19"/22" [at least] use the same boards as Polariods.
They are both OEM built by Funai.
I think only the plastics are different between the two.

.

[Krankshaft]

Re: 19 polaroid tla-01911c

I'd eyeball the inverter transistors (probably in those 4 pin packages) next to the inverter transformer.

After verifying that the main PSU is functioning of course.

One side of the inverter transformer looks a little dark (maybe a shorted winding)? From here it looks like alot of heat action was going on there.

These Polaroids are just abysmal I like to say they're picture perfect crap .

[BADHIGEEN]

Re: 19 polaroid tla-01911c

PCBONEZ I had given up for now but I will dig that board out and get a few more pics there may be hope for this set with KrankShafts 2 cents.

[Dennis44]

Re: 19 polaroid tla-01911c

Hi I'm new here. Thanks for a neat forum. I grew up on Vacuum tubes so LCds are new.
I have the same tv with the same problem. None of the capacitors appear bad.
Mine has procon and hec capacitors.
If the set has been off for some time it will stay on longer but the screen does seem to be noisy. I was wondering if there are some basic voltage measurements/ripple I should look for. If a voltage is cut off, can any of the plugs going to the lcd be removed to see if problem goes away?

Thanks, Dennis

[Dennis44]

Re: 19 polaroid tla-01911c

Not sure if anyone is still checking this thread. I did go ahead and replace 14 capacitors. I used Panasonic FC series. I have the same symptoms. Unit powers up for a few seconds then shuts off. You can see the "Polaroid" logo appear just before it shuts down. If I disconnect the four cables that I assume go to the panel lights it will stay on and the audio plays. I would appreciate any suggestions. Where can I get a service manual or just a schematic diagram?
Dennis

[Scenic]

Re: 19 polaroid tla-01911c

if it works as soon as you disconnect the CCFLs, it's probably the same problem as in my 19" Proview LCD: bad CCFLs overloading the inverter (-> OLP (OverLoadProtection))

but it could be something else, especially since the whole TV turns off (?) with the CCFLs connected to the inverter.. (usually only the inverter turns off leaving you with a "working" TV/LCD, but no backlight)

[Dennis44]

Re: 19 polaroid tla-01911c

Actually only the back light shuts down. The audio does stay up. At first I had the source to the tv set to PC and there was no audio anyway. If it does not sense a vga signal it shuts down. I was able to change it blindly to tv input.
I am not as familiar with LCDs. I will check for shorts etc to the CCFLs. Are there any ohmic values I should expect? I also need to read up on the basics of LCDs.
Thanks for you input.

[Dennis44]

Re: 19 polaroid tla-01911c

Well it seems to be working again. I was trying to test the currents in each of two ccfl that are in series. I identified that the two series pair currents did not match. When I swapped the lower connections with the upper connections it started working and has been for several hours. I may have not labeled the connectors correctly to start off with.
So it appears that replacing the capacitors did fix this set after all.

[Dennis44]

Re: 19 polaroid tla-01911c

FYI,

I am so sorry I have not gotten back on this forum to update the problem. Moving the wires around only solved the problem for awhile. Eventually the problem reoccurred.
The way this system is set up the four wires only go to 4 lamps. It really should not matter where they are plugged in from what I can tell.
I am waiting to see if I can get a service manual for this tv. That way I can make better judgments as to what is not normal as far as voltages etc.
Dennis

[Krankshaft]

Re: 19 polaroid tla-01911c

Give me the part number on one of those 4 pin packages near the inverter transformer.

These look like the driver transistors for the inverter if so one may be shorted.

[mjbsweet]

Re: 19 polaroid tla-01911c

I just got done changing out the 14 caps, some had rings around the leads but nothing out of the ordinary. It seemed to solve to problem for about 1 min then I heard a sizzling (high pitch buzz) no smoke but a light flicker on one of the 4 lamps. I turned it off and restarted did same thing twice, now we are back to the same problems. would you recomend the trans drivers next? I can have the board out and send a pic if needed.

[Dennis44]

Re: 19 polaroid tla-01911c

Give me the part number on one of those 4 pin packages near the inverter transformer.

These look like the driver transistors for the inverter if so one may be shorted.

Hi Krankshaft,
The numbers on the packs are 4511GD.

Maybe I can locate an o'scope to see how the signals look. Just looking at the input voltages with a dvm does not show any differences in the dc levels or the ac levels.
It almost seems like if I change the load I can make the set work for awhile.
I have added some 820k resisters in place of the lamps and the drivers seem to stay on although I have not left them on very long. I thought by only using two lamps I would reduce the load. This worked for awhile then it started shutting down again.

Thanks for you help.
Dennis

[Krankshaft]

Re: 19 polaroid tla-01911c

Here:

http://www.alldatasheet.com/datashee.../AP4511GD.html


They are one P and one N channel FET in one IC.

DMM to diode check measure from a S1 to G1 reverse probes measure from D1 to G1 reverse probes. Do the same for S2 (2nd FET designation) in the same IC. Look for any shorts on both ICs.

If they check out fine you're going to need to try some test CCFLs on the inverter.

[PlainBill]

Re: 19 polaroid tla-01911c

Here:

http://www.alldatasheet.com/datashee.../AP4511GD.html


They are one P and one N channel FET in one IC.

DMM to diode check measure from a S1 to G1 reverse probes measure from D1 to G1 reverse probes. Do the same for S2 (2nd FET designation) in the same IC. Look for any shorts on both ICs.

If they check out fine you're going to need to try some test CCFLs on the inverter.

Krankshaft is correct. The symptoms point to a problem with either the CCFLs or the inverter. It could be anything from a bad solder joint to a shorted turn in the transformer.

The usual design senses both the voltage across and current through the CCFLs. If these are out of specs for ANY CCFL, it shuts down the inverter.

PlainBill