Samsung le37s62b - have no idea what is wrong

[Joe Black]

I got this TV for free, and would like to use it, although it's only HD ready.

However, I have no clue what problem it has -it saomething like polarisation, pixelisation, colour shade problem, blur, but at the same time isn't.
Will try to upload pics.
Also, I just can't say if menu looks good or is just as bad, as menu is just white letters, and no coloured pictures.

I got impression that it's worse when TV is cold, though.
Any suggestions on how to determine what's wrong? PS looks pretty decent, and voltages too.

[diif]

Re: Samsung le37s62b - have no idea what is wrong

I'd guess at the AS15 gamma ic on the tcon.
There are test points on the tcon to measure the voltages to confirm.

[Joe Black]

Re: Samsung le37s62b - have no idea what is wrong

Oh, that's cool.
Ofc, the T-con is bolted in the metal casing, but now you said that, I'll dig it out and mesaure (hopefully with your help)

If it's T-con, I'lll have to buy it, since I have no experience soldering that packages, probably would destroy it.

That's why I wanted to determine is menu OK or not, supposedly if menu is OK T-con is bad, and if menu is not OK, then MB is gone.
But just can+t come up with a verdict.

[diif]

Re: Samsung le37s62b - have no idea what is wrong

Yes, there's usually a metal cover over the tcon, usually there are thermal pads on a couple of the ics and sometimes the AS15 chip.

[Th3_uN1Qu3]

Re: Samsung le37s62b - have no idea what is wrong

95% sure that changing the Tcon will solve your problem. The AS15 IC is a fairly small chip and only costs a few dollars, if you have or can borrow a hot air station you could try practicing on your damaged Tcon even if you have no intention to fix it. Learning new skills is always a good idea.

[maxvalutech]

Re: Samsung le37s62b - have no idea what is wrong

Definitely t-con is my bet and should be a fairly easy cheap fix as long as its a standard fitting and not direct to screen.

[budm]

Re: Samsung le37s62b - have no idea what is wrong

Is this your T-CON board?
Chunghwa LCD panel 370WA03C04G

[Joe Black]

Re: Samsung le37s62b - have no idea what is wrong

Is this your T-CON board?
Chunghwa LCD panel 370WA03C04G

As usual, budm is correct. Exactly that T-con and panel says 370WA03 and some other diferent numbers, my guess is that's it.

Tried to measure those points, I'll make a list of Vs. But at first glance, they seem to ascend/descend as they should (according to some guy on Youtube that is)

[Joe Black]

Re: Samsung le37s62b - have no idea what is wrong

Tried to measure test points at connectors. Here goes:

1st and 3rd connectors:
1st row of probe points - 1.19V
2nd row - 1.25V

2nd and 4th connector:
1st row of probe points:
1.46-3.60-4.16-7.24-7.99-9.40-9.90-10.93-12.60-0.00V(few mV)

2nd row:
1.40-3.05-4.18-4.78-7.16-8.01-9.57-10.41-12.45-0.00-13.92V

If that's what I should've measured in the first place

/also, I took a look on the ICs, swapping looks doable after all.
Did they have to pack T-con this way, metal plate was so hot, and no thermal pads at all..

[diif]

Re: Samsung le37s62b - have no idea what is wrong

Those test points should be marked to make reading the voltages a bit easier.
But looking at then there's a couple of bits that look a little off.
What's the markings on the 48 pin ic on the right hand side in post #7 ?

[Joe Black]

Re: Samsung le37s62b - have no idea what is wrong

Yes, they're marked, but I figured that marks not telling much as they say ie. TP 334, TP 335, TP 336 up to TP 447 (example)

What's the markings on the 48 pin ic on the right hand side in post #7 ?

AS19-HG
0739
B7630P43

[diif]

Re: Samsung le37s62b - have no idea what is wrong

Do a search for AS19-HG. Similar but not compatible with the AS15. I buy mine from ebay or more commonly Aliexpress. They aren't very expensive at all, but they are quite sensitive to heat so it might be worth buying more than one.

[budm]

Re: Samsung le37s62b - have no idea what is wrong

HG has exposed pad on the bottom of the IC that is soldered to the copper plane to transfer the heat so it will take a bit of careful works to remove the IC.

[Th3_uN1Qu3]

Re: Samsung le37s62b - have no idea what is wrong

Definitely not the job to do with just a soldering iron, but a cheap hot air station will do the job easily. Don't forget to apply flux before, of course.

[Joe Black]

Re: Samsung le37s62b - have no idea what is wrong

Will try my best, and will keep an eye open for cheap boards, as I might need one.

[Joe Black]

Re: Samsung le37s62b - have no idea what is wrong

they are quite sensitive to heat

AND they have that large pad underneath. great

I have found AS19-H1G, and mine is AS19-HG.
Can I order H1G?

According to datasheet:

H: Exposed pad (3.05x3.05 mm)

H1: Exposed pad (5.0x5.0 mm)

[diif]

Re: Samsung le37s62b - have no idea what is wrong

AND they have that large pad underneath. great

I have found AS19-H1G, and mine is AS19-HG.
Can I order H1G?

According to datasheet:

H: Exposed pad (3.05x3.05 mm)

H1: Exposed pad (5.0x5.0 mm)

Yeah, I don't think the size of the ground pad will be an issue.

[budm]

Re: Samsung le37s62b - have no idea what is wrong

If there are traces next to the copper plane for that small size exposed pad and you use larger exposed pad then you may short out the traces.

[Joe Black]

Re: Samsung le37s62b - have no idea what is wrong

If there are traces next to the copper plane for that small size exposed pad and you use larger exposed pad then you may short out the traces.

DO'H!

Well, I ordered 2 already, guy says they're HG although on pics ICs are H1G... apparently wrong pics, said the seller.

Perhaps I'll find out about eventual traces.

(Already imaginig ways to put insulation tape over in my head )

[Th3_uN1Qu3]

Re: Samsung le37s62b - have no idea what is wrong

If you have clearance issues, use Kapton tape and a sharp blade to cut it. Totally doable. You have to clean the board of flux beforehand and only use a small amount of flux for the sides of the IC when soldering it, don't apply any on the ground pad as the adhesive on the tape will be rendered useless by the flux.

Pro tip for soldering new QFN ICs successfully: Apply some flux to the sides and a tiny bit of solder to the tip of your iron, then tin each pad of the chip. You may need to use a magnifier glass for this. QFNs are designed to be soldered using solder paste, they do not have enough solder on them to be make a good connection without it. Since you will not be using paste, pre-tinning the pins will ensure there is enough solder for proper contact and you won't need to touch them up with the soldering iron after it's soldered to the PCB. Also do not clean the old solder off the board before attaching the replacement chip. Only use the iron on the sides if you get blobs coming from underneath when you press it down while using the hot air tool.

That's a lot of solder in one paragraph.