Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

[selldoor]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

I have been on holiday - these random breakdown are always difficult to trace. Some of us have had to almost completely reflow all the joints more than once to fix and it could be a small ceramic cap that is cracked and shorting or a resistor/diode going open.
When it is on again try heating sections or flexing the boards with a non conductive rod to see if you can get it to go off (Gently though )

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

yeah i need to get my hands on a hot air gun already... the TV is again working of course. i unplugged all the bulbs from the transformers and tested them one at a time. each one makes a flash for a second and then turns off. then i plugged them all in and it works again. still cant get the cfl light probe thing i made to do anything though....

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

ugh! the tv was working for over a month straight with no problems and then just yesterday it starts going out again. i unplugged all the wires going to the backlights, and tried them one at a time to see which ones make the screen flash or not. some lamps would flash, others wouldnt. then they all wouldnt flash. there doesnt seem to be any pattern to it. whats going on there when i turn it on and it doesn't even flash at all? shouldnt at least some of the lamps come on and then go into shutoff mode? what does it mean when sometimes they will flash and sometimes they wont at all?

and how exactly should i do the CFL test? will it only flash quickly during start up? do i have to have all the lamps disconnected, connected, or just the transformer im testing?

i tried it on a working TV and it made the backlight go out. luckily it came back on when i restarted the TV... it never lit up the CFL bulb. what's going on here?

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

damn tv is working again and i pressed all over the inverter board and nothing is making it turn off...so it cant be some hairline fracture or loose connection can it? and if its a bad lamp then why cant i track down the one lamp that is bad? when its not turning on, most of the lamps wont flash if any at all... and then boom they all just work.. frustrating cuz i cant ever sell this thing!

[Caleb]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

If it gets too frustrating you can always sell it as a "fixer works sometimes", It doesnt have to be just 1 bad lamp, it could be several that are hovering near the bottom spec and when one or more goes below it triggers the error circuitry, could be a bypass cap out of spec or a hundred other minor things, Heat, cool, prod and you may get lucky to isolate.

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

ok now its doing something different. i got it working last night for an hour or so...then i tried to hook it up to a PC and that was working fine. i unplugged it to hook into another PC and the screen just never came back on. so now its not working again. cant get backlights to flash. tried leaving it unplugged overnight, nothing... but now its doing this weird thing where when i press power, it starts up (makes the chime) and then like 10 seconds later it "starts up" (chimes) again.. like its in some kind of startup/shutdown loop. it doesnt make the shutdown chime though.(they are different chimes) sometimes it does it a couple times, then stays on. and sometimes it just does it over and over in an endless loop. it does this with or without the inverter plugged into the mainboard.

while its "in the loop" no amount of pressing the power button will produce the shutdown chime


starting to make me think maybe its NOT the inverter...

[stj]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

startup caps on the freshhold maybe.

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

how can i test that?

[stj]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

heat them, freeze them, replace them.

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

ok which caps are the "startup caps" then? so ill need a blow dryer, and a can of compressed air?

[stj]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

anything under 100uf that is near a controller i.c. is a good suspect.

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

well an interesting thing happened...
since ive been buying/finding/being given all sorts of TV's lately, i came across a very similar model to this TV
the SAMSUNG LN32A300J1DXZA
it looked like it maybe had a bad TCON as you can see in the pictures.
turns out the LN-T3242H uses the same panel, and therefore the same TCON and same inverter board.
first instinct i had was to try the inverter board from the LN-T3242H
in the LN32A300J1DXZA to see if it really was a bad board as i was suspecting.
as i expected, the backlights would not come on.
so then the next thing was to try the known good inverter board from the LN32A300J1DXZA in the LN-T3242H
since last i checked, that was the only thing wrong, i thought for sure this would result in a working TV.
but when i turned on the LN-T3242H, it didnt make the good chime..it just made a long beeeeeeeeeeeeep that lasts like 20 seconds and then finally goes off for a while...then the tv tries to restart and makes the long beep again, and does this over and over again. no backlights, no nothing...
seems like the motherboard is throwing some kind of error code and shutting down
after unplugging the set and holding power button down for like a minute, and plugging it back in, i was able to hear the good chime, but then shortly after it went into the bad beep again...
i tried putting back in the original inverter, disconnecting the inverter, the TCON, speakers, button board, anything i could think of but the beep was still there (well not when i disconnected the speakers, but as soon as i hooked them back in it was there)
so it looks like i got some kind of motherboard issue now with this TV.
but then i realized that since the TCON were the same, and the TCON in the LN-T3242H was known to be good, i could swap them and at least see whether i had bad TCON or bad panel in the LN32A300J1DXZA...
after swapping the TCON, the LN32A300J1DXZA is a perfectly working TV!
this is the first time i have collected enough tv's to actually be able to swap parts. usually they make everything different as fast as they can!

anyway im real happy about fixing this new TV but i'd still like to figure out what's up with the original TV that now has a motherboard problem. since i have parts to swap out, i think i should be able to do it.

it even looks like the PSU and motherboard can be interchanged ...the connectors look the same but the PSU and motherboard's guts are definitely different. similar circuits, but different components... i didnt want to try it yet without asking for advice since i have one good working TV out of the deal and i'd feel pretty dumb if i blew it by trying to test the other ones PSU on it... how can i know fore sure if that would be safe?

or better yet, how can i troubleshoot the motherboard and stop it from going beeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeep??

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

beeeeeeeeeeeeeeeep?

[Caleb]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

You would have to check all the pins on each board have the same pinout. Samsung sets usually have a legend of each connector silkscreened nearby. Then you need to power the board up out of the set and test voltages and make sure they are in spec. If everything matches then you should be able to swap without causing damage. As to the long beep you may have corrupted the eeprom, depending on the model you may be able to reset it by jumpering some of the pins through a power cycle.

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

oooh can you tell me any more about this jumpering of pins? i sold the working samsung already so i wont be swapping power supplies or motherboards any time soon...

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

ok i have read some about jumping pins on the eeprom chip to reset it. just gotta figure out which is my eeprom chip, find the datasheet for it...and then...how do i know which pins to jump together?

[Caleb]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

It depends on the eeprom.... you'll be looking for an 8 pin ic, you will have to pull data sheets to see what pins are the reset.

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

ive been looking all over the service manual and i cant find eeprom anywhere...is this the same as "flash memory" ?

there are at least 10 IC's with 8 legs on the front and the back of the board...

[Clydeuk]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

I think the ic is a 24C32, 24C64 or 24C128, something like that. Not sure about the jumpering, we just used to replace them with blanks which the set then programmed at first power on.

[triplefour]

Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.

ok i found in the service manual where it says eeprom.
in the parts list it says its in location IC112
and in the block diagram it says EEPROM 24C256 and says its connected directly to the main ATI chip.
i took off the metal shield to get to the main ATI chip and hopefully find this eeprom.
but i cannot find a chip that says 24C256
and i also cannot find a location IC112
i have looked at the board for at least 30 minutes now and i am just not seeing it.
this is the correct service manual, and the pictures of the boards look identical...