Polaroid TLA-04011c Red Light on, no power on

[PlainBill]

Re: Polaroid TLA-04011c Red Light on, no power on

lovely.... lol i was probing the caps with the multimeter in diode mode, checking to see if i could find any that had a direct short but founf none. HOWEVER, i did notice that all the 16v 220uF caps would measure around the same except for 2 of them. those 2 would go to infinite while none of the others would. Is that a sign of a bad cap??

No.

The problem COULD be a bad cap, but I'd suspect otherwise. One thing I suggest is checking the LDO regulators on the main board. They are one of the few readily identifiable and testable components on the board.

According to information I found, the 200-107-gt321xa-Bh can be used as a replacement for the 200-107-gt321xa-Ah

PlainBill

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

awsome ldo regulators do u know off hand how to check them or should i check it out online? either way, thanx a million i appreciate it yer the man PlainBill

[PlainBill]

Re: Polaroid TLA-04011c Red Light on, no power on

awsome ldo regulators do u know off hand how to check them or should i check it out online? either way, thanx a million i appreciate it yer the man PlainBill

As usual, retiredcaps has an excellent description of the process. I'll do my best.

A common LDO type is the xx1117-vv family, usually found in the SOT-223 package. xx represents two or three letters which normally represent the manufacturer. Common ones are AS, CLM, IRU, REG, TS, etc. vv identifies the output voltage - Typically 18, 25, and 33, representing 1.8 volts, 2.5 volts, and 3.3 volts. If vv is missing, it's an adjustable regulator.

I've attached a picture of the SOT-223 package. The pins are numbered left to right 1, 2, and 3. Pin 2 is electrically connected to the tab. Pin 1 is Gnd, or the Adj pin. Pin 2 is the output, Pin 3 the input.

Testing is easy. Measure the voltage from circuit board ground (NOT pin 1) to pin 2. It should correspond to the voltage designated by vv. If it doesn't check the voltage on pin 3. It should be at least 1.2 volts higher than the output voltage designated by vv. Now, since the board is not receiving main power, most of the LDOs will have no input voltage. What you hope to find is an LDO regulator with 5V in (from 5Vstby) and some non-standard output voltage.

PlainBill

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

ok ill do the checks. i did notice that this component had gotten really hot. hot enough to the point that the solder on the legs of it is pitted and the packaging is discolored. i circled it in the picture i attached. sorry for the not so great photos, my camera sux ass when i get it that close, i even zoomed in and out and its just a crappy camera.

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

ok after doing the checks on the ones labeled xx1117-vv, they all measured out to be the same. from board ground to PIN1: 2.08vdc PIN2:3.35vdc PIN3: 4.95
Now, in the picture i attached, the one circled is labeled U35, marked with UTC 78TO5AL i checked it for shits and giggles and this is what i got..... From board ground to PIN1: 11.89vdc PIN2: 0VDC PIN3: 4.98vdc. i dont know if that is relevant or not. Sorry if im jumping ahead.....

[Scenic]

Re: Polaroid TLA-04011c Red Light on, no power on

78T05AL is a beefed up version of the 7805 linear voltage regulator. basically (as in how they work) the same thing as those xx1117-vv.
output 5V (05 at the end) with 3A (indicated by the T).
you measured 4.98V, so that's probably ok.

That AIC1084PM is an adjustable voltage regulator capable of 5A
http://www.alldatasheet.com/datashee...C/AIC1084.html

to find out if that's ok, you would have to find out what voltage it's supposed to put out first (as it's adjustable, not fixed voltage like the others).

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

ok thanx for the info Scenic, really appreciate it. Well now im at a stand still, not quite sure what to check from here. Its gotta be something that can be replaced rather than getting a whole new board.cuz if i have to go that route, ill be screwed. lol

[PlainBill]

Re: Polaroid TLA-04011c Red Light on, no power on

ok thanx for the info Scenic, really appreciate it. Well now im at a stand still, not quite sure what to check from here. Its gotta be something that can be replaced rather than getting a whole new board.cuz if i have to go that route, ill be screwed. lol

I don't see why. There are several compatible main boards on eBay available for under $130 delivered. Granted, a Polaroid is a poor excuse for a TV, but your friend could still wind up with a working 40" TV for about half the price of a new one.

PlainBill

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

true i guess yer rite.... i just have a thing for having to fix something if i think i have a chance at fixing it lol

[crtfool]

Re: Polaroid TLA-04011c Red Light on, no power on

Here's an idea - Since you are fixing it for your friend, why don't you get the board on eBay - make sure that the TV does work properly, then very carefully take measurements and comparisons between both boards - you can use this as a learning exercise for your own experience, and you may actually determine what is wrong with the original board. You are going to charge your friend for the repair anyway, and you can sell the original board on eBay if you do fix it - WIN WIN.

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

well thats a good idea only thing is that im broke rite now and im not gonna charge them to fix it..... because it happened to die when i brought a desktop computer over to their house and hooked it up to the tv with the vga cable. the tv turned on, showed the desktop and we played around in windows for about 5 min, then i rebooted the pc to make sure it was gonna boot properly and while it was rebooting the tv screen went black. as if it went to standby mode and just never came back on

[crtfool]

Re: Polaroid TLA-04011c Red Light on, no power on

The red light of death is very common on these Polaroids - I am quite sure that you connecting a VGA computer to the TV had absolutely nothing to do with the failure, but trying to convince your friend of that will be impossible. I have had similar situations happen to me, and there is no way that anyone will believe that it was just a coincidence.

Here is an example that happened to me recently - I have 2 laptops that were working perfectly - I shut them down properly, and when I tried to turn them on again - NOTHING! The second 1 died about 3 months after the first. Both of them are dead motherboards.

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

EXACTLY! so im not gonna even try to convince them or argue about it, its one of those thing were ill just bite the bullet on it. lol

[cadiman]

Re: Polaroid TLA-04011c Red Light on, no power on

I have had no power supply issues with these.

I have had three with main board problems. I found a good used one on ebay for 22.00 (The whole module).

I had a lot of green pins on the plug connection where the module plugs into the tv also.

I think these also had the amf1116s fail.

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

i know its gotta be sumthing thats staring me right in the face. i just dont know if and how to check the caps. can i do it with a multimeter? if so do i check them in circut or out of circut? im willing to learn if someones willing to teach. im not to proud to admit when i dont know how to do something. lol

[crtfool]

Re: Polaroid TLA-04011c Red Light on, no power on

You need an ESR meter to check capacitors.

I highly doubt that it is a bad capacitor - I checked every cap on mine when I was troubleshooting, they were all perfect. It probably is an IC failure, and they can't be tested without documentation.

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

ahh i see, thanx for that info. so basically i could make a list of all the ics and get their data sheets online then test each one??

[crtfool]

Re: Polaroid TLA-04011c Red Light on, no power on

ahh i see, thanx for that info. so basically i could make a list of all the ics and get their data sheets online then test each one??

Theoretically, yes - but very unlikely that you will get any info on most of them, and even more unlikely that you can buy replacements.

[Dgtech]

Re: Polaroid TLA-04011c Red Light on, no power on

You need an ESR meter to check capacitors.

I highly doubt that it is a bad capacitor - I checked every cap on mine when I was troubleshooting, they were all perfect. It probably is an IC failure, and they can't be tested without documentation.

Not really true. I use a Fluke 87-III that has a capacitance check function on there. It will not measure ESR but it will find a bad cap by measuring the uF (micro farad) value. For instance, good 2200uF caps will measure a little high at 2500uF. I have a bad one in a power supply that measures low at 2000 uF. Sometimes you'll get no reading at all on a cap that will need to be changed. The ESR is important also, however, I never use one. If I manufactured caps, I might use one. I just swap out bad caps with new ones. There are lots and lots of TV's out there with high ESR caps in them that work just fine.

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

Dgtech..... as you were saying about checking the caps, do i check them in or out of circut??