Electronics > Repair
LCD screen model M270HTN02.0 need help in identyfying a component
soflesone:
Hi, I would like to ask you for help in identifying a component on the T-con of an AUO M270HTN02.0 matrix the T-con model is 27M14-C05.
Short story, as it happens with this matrix, most often damaged element is N mosfet marked 12h34 and so it was in this case, as you can see on the picture, I replaced it with A09T (I know it's not perfectly straight soldered but it's just being soldered at the moment) unfortunately the problem did not disappear the screen was still not displaying the content and was glowing white. The gate of the replaced mosfet had 0.17V so it was suspected that P303-19 was probably defective. After soldering out P303-19, the resistance on the above-mentioned gate returned from 1.5kΩ to 20kΩ. Unfortunately, this still had no effect and after starting P303-19 was again damaged, heated in the upper part at pins 13 and 14 and that's where I started looking for further problem.
It turned out that the element marked on the photo as W1 is shorted on all pins, unfortunately I am not able to clearly determine what this element is and here I ask for help in determining this, from my search I found several options:
on this page https://www.s-manuals.com/smd/w1 the W1 circuit is labeled as a Zener diode
while on this page: https://www.hotenda.com/marking-code/se ... st/W1.html it is marked as NE687M13 transistor https://datasheetspdf.com/pdf/574855/CEL/NE687M13/1
and on this page http://tromil.pl/wp-content/uploads/201 ... d-cz.2.pdf there is information that it is a PNP transistor with code BFT92 and after searching this code you can find transistors with markings W1w, W1s, W1p where mine is clearly marked W1
I will be very grateful for any help :)
fzabkar:
There is a similarly labelled W5 component at Q301, so I would think that W1 is a BJT transistor or MOSFET.
Also, Q303 is marked "1CH18", so I'm guessing it is manufactured by the same company as "12H34".
Q303, D303 and L304 appear to form a boost converter, with the output voltage appearing across C327 and C328. Q303 appears to be a low-sat NPN BJT or N-channel MOSFET.
Q305 appears to be a 2DD1664 manufactured by Diodes Inc:
https://www.diodes.com/assets/Datasheets/ds31143.pdf
Perhaps the others are also manufactured by Diodes Inc?
DavidAlfa:
This pdf has data for the P303-11, which might be the same thing with a different voltage output?
Pins 13 and 14 are connected to a mosfet, so that's probably that .
DavidAlfa:
The mosfet might be AO3401L.
The datasheet doesn't show the marking.
Edit:
Check out this schematic, page 35, the circuit looks very similar, but uses n-ch fet (AOH3106)
fzabkar:
The marking code for AO3401L appears to be "A1xx":
http://www.smdmark.com/en-US/search/code?id=a1xx
https://www.google.com/search?q=AO3401L&tbs=isz:m,itp:photo&tbm=isch
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