Samsung LCD LE37A656A1FXXC , trouble starting up!

[Moreno83]

Hey Guys ,

I bought this tv with a T-con problem , replaced the chip and screen is working as it should. However , the tv has some issues.
When i remove the power from the tv and plug it back in the following happens:

1) Black screen , led is blinking.

2) After 5 blinks the backlight lights up but goes away and then after 10 blinks ( from start ) screen lights up again and it goes back to black. And the backlight turns on/off for a few times and then it comes with either a black screen or a no signal screen.

When i turn the tv off with the remote the standby led stays on and when i turn the tv back on it works inmediately.
Does this type have issues if there is no cable/dvd input? Or is this a powersupply issue? No blown/swollen caps!

Dont have pictures yet , im at work.

Any ideas?

[Moreno83]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Ok , i tried the following :

With the tv displaying a good picture on HDMI , i turned the tv off. ( Left the HD receiver on ).
Turned the tv back on , i get a white screen with sound and a blinking red light. ( Really fast blinking ).

Then after a few minutes it goes to standby , turn the tv back on and i get a good picture which stays good while the tv is on.
Maybe a bad solder on the AS15 chip?

Any idea's?

[Moreno83]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Does this power supply have pull up resistors? Tv is acting like it's missing the power to display the picture after 5 blinks. ( Other samsung tv that i have shows a picture after 5 blinks , this one also when its working normally ).

[selldoor]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

May be start up caps on the power supply

see first post on this forum re pictures.

[Moreno83]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Will post some pictures when i get home but i already replaced all the normal caps! Small PS

[flocko]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Try the set with T.Con disconnected to see if it fires up, I have had bad AS15 chips that when fitted the set would not come out of standby ? Flocko

[budm]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Can we see good clear pictures of both sides of the main board, power supply board?

[Moreno83]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Thx for the replies guys! Much appreciated!!

Here are the pictures , tv is acting like its in a bootloop or something...

[Moreno83]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Back of the PS

[Moreno83]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Tv acts the same when the T-con is disconnected from the other board above the main board. ( 4th picture )

[selldoor]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

OK - now try as Flocko suggests.
What caps did you use as replacements - Make/series
Did you rplace CM807 and the one next to it?




EDIT see you just did that
EDIT2 Maybe not you need to disconnect it from the MAIN

[Moreno83]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

They are different brands but all from china.

Antel/henxing/BRC/Hong and i always use them and never have problems with these...

[Moreno83]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Ok i disconnected the 2 boards ( T-con and … ? ) and the TV starts up , red light is blinking really fast but i hear sound. It starts up quicker then normal.

Im suspecting the board on picture 4 , is that a video board?

[budm]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

It looks to be FRC (Frame Rate Conversion) board.

[selldoor]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Im suspecting the board on picture 4 , is that a video board?

It will have a part number on it somewhere and perhaps the number on the barcode sticker?

[budm]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

The numbers as printed on the barcode sticker is the PCBA (Printed Circuit Board Assembly) number that you need to match, not the blank board P/N as printed on the board with white letter.
The picture is not clear enough for me to read the numbers on the barcode sticker.

[Moreno83]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Thx for the replies but i found the problem.

The backlight converter was the problem. There are 8 capacitors on that board with 270uf value.
Replaced all of them with 220uf+47uf caps and tv turns on after 5 blinks and is working perfectly.

Thx again!

[nomoresonys]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

i it blew the 270 caps, won't it blow the 220's even faster?

[budm]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

"Ok i disconnected the 2 boards ( T-con and … ? ) and the TV starts up , red light is blinking really fast but i hear sound. It starts up quicker then normal."
Hmm, that is strange since you get the sound so the 12V/24V power supply for the sound (12V), and 24V for the inverter are working.
But it is good that you found the cause of the problem.
BTW, can we see the inverter board.

[Moreno83]

Re: Samsung LCD LE37A656A1FXXC , trouble starting up!

Hey guys ,

No its not gonna blow the board. I used 220+47uf = 267uf/50v.
I tested the tv and it was working fine untill i put the backcover back on and i got a few lines on the screen.....
Looked like 1 vertical blue line and 2 vertical red lines.

Removed the backcover and now tv turns on , backlight comes on and stays on and i got sound but no picture.....

So i removed the tcon and frc board but still the same , it blinks 3 times and on the 4th time its starts blinking really fast.
Im again suspecting the FRC board , it has the FULL HD chip on it.

I'll make some pictures.....