AUO T37XW02 T-Con board, transistor identification after short-circuit

[yoritomo]

Hello all

I have a T-con board AUO T370XW02 coming from a Samsung Le37A330J1, originally i had a bad gamma chip, pale image and incorrect colors .... Test point values was bad then i replaced the AS15-F .

Not the first one i am doing it but this time, I missed to see 3 pins in short-circuit, 25,26,27 , i got the fuse B201 blown and a transistor Q101, this one has a fake marking code "25819" could not find anything searching on it. I joined a picture , from the net, with some details this is not mine don't search the blown parts . Simply i don't have a camera here.

Please anyone can tell me what could be the real number of this transistor or equivalent please ? Thank you very much

[tom66]

Re: AUO T37XW02 T-Con board, transistor identification after short-circuit

B201 is not a fuse it is a ferrite bead. It is feeding the panel, if it is shorted then it may be because the panel is damaged.

The transistor is likely to be some kind of N-channel MOSFET with logic level rating, e.g. FDN359AN although the exact part may never be determined if you can determine the pin out then you can find a suitable or close substitute.

[yoritomo]

Re: AUO T37XW02 T-Con board, transistor identification after short-circuit

Yes right it is directly going to the panel connector, it would be a bad news, i will check a bit in this direction, the 3 pins shorted was the inputs CI DI and EI, how comes it would destroy the panel .

[yoritomo]

Re: AUO T37XW02 T-Con board, transistor identification after short-circuit

Hello Tom66 and everyone

I have some further informations .

B101 was still connected to the ground, by the gamma chip incorrectly soldered, when i removed it, no more short circuit to ground to ground. Then now it still be the transistor to replace. I joined a picture of my test, I could find a diode junction in the transistor, I wrote N,P on the pic to indicate the probes in forward direction.

I could find the schematic of this board here

We can see the transistor in 2nd page of this schematic, unluckily they was bad enough to replace real references... The diode i could measure is surely the rolling diode following the schema.

Thank you for your help

[yoritomo]

Re: AUO T37XW02 T-Con board, transistor identification after short-circuit

Hello

When comparing the junction i found, it does not match with FDM359AN, the junction is reverse on it, I don't know where to find a good online tool for cross reference on it, the once I used did not find any Supersot-3 packages entering the values. I rarely had to search for unknown SMD references, I am not clever on it.

As well I don't guess what should be the value of the ferrite bead.

Thanks for your help

[yoritomo]

Re: AUO T37XW02 T-Con board, transistor identification after short-circuit

It is not a N-channel but a P-channel, i will order IRLML5203GPbF which is similar features like the one you told. I hope to be lucky

[yoritomo]

(Solved) AUO T37XW02 T-Con board, transistor identification after short-circuit

I finally received the transistor which I mentioned above, and installed it as well as a new ferrite bead which I could find in an old t-con board, then now everything is working fine.
It is solved, next time I will check better if soldered correctly !! lost time and money :-s

Thank you for your advice about the transistor Tom66.

[Coldblackice]

Re: (Solved) AUO T37XW02 T-Con board, transistor identification after short-circuit

I finally received the transistor which I mentioned above, and installed it as well as a new ferrite bead which I could find in an old t-con board, then now everything is working fine.
It is solved, next time I will check better if soldered correctly !! lost time and money :-s

Thank you for your advice about the transistor Tom66.

This thread is just what I need! Thanks much for the info + investigation. I also have a 37-inch T-Con board very similar to yours. The AS15-F went bad, I soldered in a new one, tried turning the TV on, then POOF, the magic smoke arose :/

I can see the scorched Q301 transistor on my board in the AVDD section, so I assume I'll have to replace that. But my worry is that other things may have also gotten damaged -- how were you able to tell that the B201 was bad?

Also, how did you go about determining what pins you shorted? I'm a novice, so not sure how to go about this other than putting a probe on one leg (out of the 48) and then dragging the other probe across the other legs until hearing a beep. But then how do you know whether it's a shorted legs vs. a common ground?

Thanks!