Polaroid TLX-04244B Image Quality Question

[jwillifixit]

So I "acquired" one of these for free the other day and it's working but has a pretty bad picture. I put a blu ray movie to it using HDMI and skin tones look reasonable but the shadows / darker areas not so much... Attached are two images. Left on each is with all settings at 50% and right is with contrast cranked to 100%. I noticed on the settings menu that there's all sorts of pre-set (cinema, soft, bright) and the "bright" seems to look the "best" but is still off.

I'll get the back off and begin a visual inspection tonight but in the mean time had a general question about what area the signal processing would go bad like this.

Thanks as always for your guidance.

[dskall]

Re: Polaroid TLX-04244B Image Quality Question

Gamma problem. Pretty sure your t-con board has the as-15 chip which is a common failure. You can replace chip or t-con depending on your skill level.

[dick_barton]

Re: Polaroid TLX-04244B Image Quality Question

I've had a similar issue with a low cost set with virtually the identical display as you show above. Changed the TCON but made absolutely no difference.

[dskall]

Re: Polaroid TLX-04244B Image Quality Question

Well he could post his t-con voltages and we could run them through the spreadsheet to confirm.

[ReeceyBurger123]

Re: Polaroid TLX-04244B Image Quality Question

This panel used is known for tab bond and gamma Ic failures. Test the gamma Ic if its good tab bond issue.

[jwillifixit]

Re: Polaroid TLX-04244B Image Quality Question

I'm going to give it a go with replacing the AS-15 I think. I'm new to all this but loving the feeling of working with you all to troubleshoot and fix. Scored a nice 47" for the cost of replacing a voltage regulator ($1.27 usd)... what a thrill!!!

So I read the hot air station threads and have one on order as well as an illuminated mag lamp (my eyes aren't what they used to be).

I'll follow through tonight on checking the voltages and post. I saw that calculator excel sheet and would love to get to a point where I understand it. ;-) I mean I get what it's doing just don't know what the values are all about.

[jwillifixit]

Re: Polaroid TLX-04244B Image Quality Question

Okay I hope I've got this right... see close up of connector. I marked up what seems to be pin 1 and it looks like they go back and forth from side to side instead of up one side and down the other...

01 = 12.01
02 = 12.01
03 = 12.01
04 = 0.007 (there's no wire there?)
05 = 0.007
06 = 0.007
07 = 1.491
08 = 1.115
09 = 1.531
10 = 1.144
11 = 1.443
12 = 1.146
13 = 0.008 (there's no wire there?)
14 = 0.008
15 = 1.279
16 = 1.332
17 = 1.495
18 = 1.098
19 = 1.511
20 = 1.127
21 = 1.517
22 = 1.128
23 = 1.463
24 = 1.170
25 = 0.009
26 = 0.009 (there's no wire there?)
27 = 1.247
28 = 1.302
29 = 1.503
30 = 1.118 (No connector over these)
31 = 0.003 (No connector over these)
32 = 0.003 (No connector over these)
33 = 3.28 (No connector over these)
34 = 0.001 (No connector over these)
35 = 3.31 (No connector over these)
36 = 3.30 (No connector over these)
37 = 0.001 (No connector over these)
38 = 0.001 (No connector over these)
39 = 0.001 (No connector over these)
40 = 0.001 (No connector over these)

Pic's are:
Overview
Close ups of main board including mark up of connector and what I think ya'll are calling the AS-15... tell me it's not the one under the heat sink rubber thing on the Control board please (anyway that one had no markings on it).

[dskall]

Re: Polaroid TLX-04244B Image Quality Question

Last picture t-con board. Upper right under brown heat sink material. What is that chip number? Also right there you have about 22vgma test points. Need all those in order. Or you can plug them in here

[jwillifixit]

Re: Polaroid TLX-04244B Image Quality Question

As15-f
0831cg
b8516257


1 = 14.05
2 = 13.90
3 = 13.75
4 = 11..07
5 = 10.90
6 = 9.95
7 = 9.40
8 = 9.13
9 = 11.70
10 = 12.00
11 = 6.85
12 = 6.20
13 = 6.10
14 = 5.90
15 = 4.41
16 = 4.16
17 = 3.83
18 = 2.86
19 = 2.19
20 = 0.53
21 = 0.43
22 = 0.29

[dskall]

Re: Polaroid TLX-04244B Image Quality Question

Looks to me like a bad gamma chip. Readily available if you have the skill to replace it.

[jwillifixit]

Re: Polaroid TLX-04244B Image Quality Question

I don't as yet have the "skill" but I have the desire to acquire it through practice and I've quite a few scrap boards around here so... I've got a hot air 2 in 1 unit on the way and will get the IC on order too. I assume the only important part of the numbers on the part is the AS15-F and the rest of it is date/lot code info. As long as I order an F and not an HG etc. I'll be fine?

EC5575-F AS15-F TQFP48 14+1 lead-free
EC5575-G AS15-G TQFP48 14+1 Green Package
EC5575-FR AS15-F TQFP48 14+1 lead-free; (R) : Tape & reel
EC5575-GR AS15-G TQFP48 14+1 Green Package; (R) : Tape & reel
EC5575-HF AS15-HF TQFP48 14+1 lead-free ( H )
EC5575-HG AS15-HG TQFP48 14+1 Green Package ( H )
EC5575E2-F AS15E2-F TQFP48 14+1 (pin40 is Vcom-) lead-free
EC5575E2-G AS15E2-G TQFP48 14 channel (pin40 is Vcom-)Green Package
EC5575E2-HF AS15E2-HF TQFP48 14+1 (pin40 is Vcom-) lead-free ( H )
EC5575E2-HG AS15E2-HG TQFP48 14 channel (pin40 is Vcom-)Green Package (H)

[dskall]

Re: Polaroid TLX-04244B Image Quality Question

I screwed my first attempt up. Blew off one of the resistors. I definitely recommend practicing on scrap boards.

[jwillifixit]

Re: Polaroid TLX-04244B Image Quality Question

I added the "optional information" to the excel file. I couldn't find a test point for VCOM but did find VCOM2.

It looks to me like this chip is a Fail but I'm having some issues with the sheet and wonder if others are seeing this same thing. See images...

Summary doesn't populate with a Pass or Fail just shows a #Ref
Detailed Results shows quite a few #Ref and #Value

Thanks... I'm sure looking forward to getting my hot air station.

[dskall]

Re: Polaroid TLX-04244B Image Quality Question

Your basic voltages look good but your gamma voltages are bad giving you the bad picture. If you scroll to top of page it will give results. As they say this is not 100% accurate

[jwillifixit]

Re: Polaroid TLX-04244B Image Quality Question

I've been lucky so far with getting units that had simple to fix common problems. For example the 47" Vizio LCD that needed a little surface mounted AMC1117 voltage regulator replaced. I figure it's not that often where the only problem is the simple, inexpensive one and you're done but I'm hoping to go 2 for 2 with this one.

[dskall]

Re: Polaroid TLX-04244B Image Quality Question

What fun would it be if they were all easy

[vinceroger69]

Re: Polaroid TLX-04244B Image Quality Question

As15-f
0831cg
b8516257


1 = 14.05
2 = 13.90
3 = 13.75
4 = 11..07
5 = 10.90
6 = 9.95
7 = 9.40
8 = 9.13
9 = 11.70
10 = 12.00
11 = 6.85
12 = 6.20
13 = 6.10
14 = 5.90
15 = 4.41
16 = 4.16
17 = 3.83
18 = 2.86
19 = 2.19
20 = 0.53
21 = 0.43
22 = 0.29

pins 9 and 10 look like the faulty area i have never changed one of these ics yet but have a few spare tcons so may have a practice as i do have a hot air station etc

[jwillifixit]

Re: Polaroid TLX-04244B Image Quality Question

... tell me it's not the one under the heat sink rubber thing on the Control board please (anyway that one had no markings on it).

As can be seen in post #9 there clearly were markings on that IC... what kept me from seeing them was the adhesive from the rubber heat sink pad.

Here's a question - the surface of that pad that was "glued" to the IC is now not smooth and flat and also has no "stick" left to it. I assume I can use the thing on the replacement IC by simply turning it over but what type of adhesive should be used to bond it to the IC?

[vinceroger69]

Re: Polaroid TLX-04244B Image Quality Question

heat sink compound like used on computer cpus? im not sure but dont see why it wouldnt work

[jwillifixit]

Re: Polaroid TLX-04244B Image Quality Question

The first reason that comes to my mind is "gravity". Unless this pad is being held in place by compression with the cover shield I'd say it would simply slide off the IC once the TV is stood up.

I think it needs to be some kind of contact cement I just wasn't sure if it needed to be anything "special".