Samsung LE32B450C4W

[liamoc74]

Got this tv in, wasnt powering..

Changed internal fuse which was blown and it started sparking at the bridge rectifer, the one at bottom right of the heat sink.

I took the board out and the negative pin was kind of burnt and solder was not there so i soldered it up and popped it back in, sparking stopped and tv came on but on the left hand side there are(were) 11 tabs, the one at the bottom left(looking at rear of board) started to heat up so i cut power and then when i was removing the board again it snapped.

Put it back in tested again and it just started to get really hot there so I ordered what I thought was the same board online which came today.

Noticed its not exactly the same but says its compatible.
Now the tv powers up, shows the menu screen for the selected channel and then the screen goes black after about 3 seconds, tv is still on. Turn it off, turn it on, same thing!

Old board on the left, new one on the right..

Any ideas..?

Thanks!!

[Fwrothy]

Re: Samsung LE32B450C4W

Maybe a stupid question but-have you tried giving a real input signal?

[liamoc74]

Re: Samsung LE32B450C4W

No tv connection in shop yet but tried on the hdmi with a laptop with working hdmi(tried on another tv).
Will get it home later on tho, test and post results!!

[liamoc74]

Re: Samsung LE32B450C4W

No joy - its just coming on and the screen flashes with picture for 2 secs and then goes off, volume continues to run..

Made a short vid to show..

http://youtu.be/Q7323o4gpdU

[liamoc74]

Re: Samsung LE32B450C4W

Anyone any ideas on this problem.??

Its a backlight prob, can still see the pic when backlight dies! The inverter is built into psu board(the one i replaced), what do in need to check or replace on this board.?

[tom66]

Re: Samsung LE32B450C4W

Check across the large 450V capacitor, yellow thing on the primary side, you should have about 390V across it. If it is low, around 320-330V, it will cause this fault, it is due to bad PFC IC (FAN7529 IIRC)

[liamoc74]

Re: Samsung LE32B450C4W

Thanks Tom - i'm getting 393V across it..

[liamoc74]

Re: Samsung LE32B450C4W

Just remembered that when the backlight connection thing broke of old board the holder also broke, for some reason it didnt occur to me until now - surely thats whats causing the backlight to die after 2 secs - tried old board again and same thing happening too - im some dope surely!!

Pic attached - whats it called.? Holder/connection.?

[tom66]

Re: Samsung LE32B450C4W

The bulbs slot into there... so it must be somewhere... I hope you have not broken the bulb (they are very delicate.) When I was working on a LE40B550 I broke the tab on the board that slots in there, I was able to fix this but it took a lot of work, good lesson learned.

[liamoc74]

Re: Samsung LE32B450C4W

Yeah thats the thing that broke, the white one at the bottom, bulbs are fine but that bottom one broke in two, pretty sure the two bits have been thrown out - damit, can i get a replacement or whats the work around.? some things just have to be learnt the hardway eh..

If i solder a cable to the bottom bulb and then connect it to the tab on the board - that do the trick!?

[tom66]

Re: Samsung LE32B450C4W

The bulbs are pretty hard to solder to (the surface is not usually designed to accept solder), maybe the best you can do is find some clip to connect or get the required part from a cracked panel.

If you do decide to solder to the bulb make sure to take it out or the heat from your iron could damage the diffuser or LCD panel.

[liamoc74]

Re: Samsung LE32B450C4W

Okay cool - worth a shot - feel so close to actually fixing this thing!!

Could i just solder a cable from "c1850" on damaged board to the bulb and return the one I ordered!

If i'm going to use old board, should i keep the pin being soldered to the bulb in the board or remove it and then attach cable.?

Sorry about all the questions, i am eager to learn how to fix these tho and i really do appreciate your time..

[tom66]

Re: Samsung LE32B450C4W

There's nothing stopping you soldering to an appropriate part of the board but how do you intend to connect to the bulb itself? It's damn near impossible to solder to them, you will have to take the bulb out of the screen, but then how will you put them back in the set if you solder them together?

[liamoc74]

Re: Samsung LE32B450C4W

im hoping i can get this to clip onto the end of the bulb..

[tom66]

Re: Samsung LE32B450C4W

Best of luck - please let us know how it goes

[liamoc74]

Re: Samsung LE32B450C4W

I will indeed - one thing tho, pin in or pin out when i solder to the cap.?

[Alastair E]

Re: Samsung LE32B450C4W

I broke one of those tabs once--Soldered a wire link in there, job done......

No need to fuss around stripping the LCD down to repair, just fish out the broken bit of tab cut the plastic slightly and solder direct to the metal of the connector in there and then to the PSU.

Simples!

[liamoc74]

Re: Samsung LE32B450C4W

im missing the connector too tho so have to find a way of attaching to the bulb..

well know how it goes in 5 mins!!

When you say to the psu alastair you mean to the cap yeah, should i leave the pin im soldering too connected to the board or disconnect and then solder.? Basic stuff im sure but im just not sure..

[Alastair E]

Re: Samsung LE32B450C4W

Well--IF the bulb is the type with a wire sticking out the end--no problem, solder (Carefully) to that.

If the bulb is the type with the silver end and no wire, then you'll need to firmly wrap some wire around the silvered end and use that to connect to....

[liamoc74]

Re: Samsung LE32B450C4W

im on the bulb now, cliped and soldered, seems solid!!

The other end tho, im going straight to a cap yeah, cap 1850 in previous pic..do i leave the pin still connected to board or remove - the reason i ask cause is current still going to go as far as broken tab with pin still in board.?? or will it take the route of my soldered cable regardless of weather its on the board or not..