Can someone tell me what is exactly Q302 (W1 marking), another mosfet and if so, part number would be appreciated !
Thank you !
Thank you to the guys at HEGE supporting Badcaps [ HEGE ] [ HEGE DEX Chart ]
Announcement
Collapse
No announcement yet.
User Profile
Collapse
-
Well no luck !! I solder a AP2334GN-HF in place of Q308, put a jumper between Drain and Source of Q9, plug everything back together and no Asus logo ...
Before I made any changes, the screen was always white and now when I turn it on, it goes white a second, then black a second, and white again before stand by (amber light)
I think AUO P303-19 is bad ??...
Leave a comment:
-
I'm going to try finding a mosfet with marking 12H34 on one of my laptop motherboards that I keep for parts and bridge SOURCE and DRAIN of the P-channel that I don't have yet and see if the Asus logo appears on the screen ??
Leave a comment:
-
Thank you lotas !
Yes after searching the internet, it is a mosfet. Either P5002CMG like you suggest or AO3400A would do the job !
Leave a comment:
-
After further investigation, I think it's a SOT-23 NPN transistor. The bottom left is B. bottom right is E and top leg is C.
With no power to the board, the two bottom legs are GND. R302 (Mark 203) keeps Base to ground, transistor OFF.
This transistor is switch ON by AUO-P303-19.
Leave a comment:
-
I found the problem. I injected +2V, 1A. The area circle in red what getting really hot to the touch, so I thought it was one of those two capacitors. I removed them one at a time and check if the short was gone but no !
Did voltage injection again and it was Q308 that was getting hot !!! Removed that transistor and the short is gone. Soldered back both capacitors and everything is good.
But I think it should be a transistor not a mosfet since there is no G D S markings ?? What do you think....
Leave a comment:
-
Yes tested with cable disconnected. I connected back the power supply to check what was the voltage at the Source of mosfet Q9 (Of course removed) and it is +12V. Should I start with +3V, 1A or go with +12V, 1A ??
Right now I'm searching online for every IC's on that board to find Vcc pin to make sure none of their power rail is shorted before injecting voltage ....
Leave a comment:
-
The 12V rail that goes to the T-con is indeed shorted ! There is a lot of capacitor on that board and none are overheated. Don't want to remove capacitor randomly, can you suggest me a way of doing this, not randomly ?
Maybe voltage injection ?
Thank you...
Leave a comment:
-
Thanks for your reply !
But I figured it out by myself. Q9 is a P-channel mosfet that only switch positive voltage to the connector (I think it's 12V). The gate is pull high by R151, so mosfet is OFF and pull low by NPN transistor Q10, mosfet is ON.
I removed Q9 and check every components around that mosfet and they are all OK.
Unfortunately I don't have a sot-23 P-channel mosfet lying around right now !!
If I'm wrong, don't hesitate to correct me .....
Thank you....
Leave a comment:
-
Asus VG278 mosfet identification ?
Hello,
My Asus monitor stop working today !! I found the problem on the main board, the power supply board is ok. It's Q9, a mosfet but I have no idea what are the specs since I don't have the schematic for that monitor !!
Can someone help me identified this mosfet ?
Thank you !1 Photo
-
Possible, maybe ! It's burn through the second layer, I think. How can I solder a new mosfet if there is no more traces, pcb pads ???
Leave a comment:
-
It's the copper trace that I rolled to the right. Believe me, it is clean !
Leave a comment:
-
Xbox Series X, is this repairable ??
Hello,
Just look at the pictures and tell me if this Xbox is scrap or repairable ?
I removed the mosfet next to the blown one to see what the traces look like ! Pictures are from top and bottom.
Thank...
-
NAD CD/DVD Player T-513 Problem !!
Hello,
I have a NAD T-513 that always display DISC Err, no matter what kind of CD I use.
I change the optical laser pickup, it was only 20$, I had nothing to lose, but it did not solve the problem !
My question is:
On a good working CD player, is the RPM always constant, because on mine, it goes up then down, up then down repeatedly ???
I check the VCC pins of the Motor Drive IC (LA6560) and +8V is present. But one thing I notice, this IC gets hot really fast ???
Do you think LA6560 is bad or the spindle motor ??...
-
Well, I'm about to give up on that scope !! After replacing many components, that were probably good, the intensity knob still don't do nothing at all, the line on the screen is at full brightness !!
The intensity modulation (Z-axis) jack at the back is for as I understand it, modulating the brightness of the spot at specific time, correct me if I'm wrong !!
What I did is connect a 100k pot to this jack with a range from -24V to +24V, but nothing happened on the screen no matter how I turned that pot …
The service manual spec says 20 p-p minimum.
...
Leave a comment:
-
Re: Toshiba TD3472AP Replacement ???
Looks like the SN5472/SN7472 are the exact replacement for the TD3472AP !!!
Thank you very much for your information truclacicr
Leave a comment:
-
Toshiba TD3472AP Replacement ???
Hello,
I search and search and could not find the datasheet for this IC !!!
What I understand it's a JK Flip Flop IC. From the schematic the pinout is:
1- Not connected
2- R
3- ground
4- J (tied to ground with 3 and 5)
5- ground
6- Q(bar)
7- Vss
8- Q
9- +5V
10- +5V
11- K (tied to +5V with 9 and 10)
12- C
13- S
14- Vdd
What is pin2 (R), pin13 (S), pin12 (C) ???
Is it (R)eset, (S)et and (C)lock ???
Thank you...
-
Re: BK Precision model 1472C Oscilloscope Intensity problem ??
I replace C337, problem not solved. I'm running out of idea !!
One leg of VR2 (Brightness knob) goes to pin 3 of IC204, I'm beginning to suspect that IC, what do you think ??
Maybe a transistor after VR2 is not good but I don't like replacing components randomly !!!
Leave a comment:
-
Re: BK Precision model 1472C Oscilloscope Intensity problem ??
D311, D312, R346, C343 are good !
Focus working as it should.
I'm going to replace C337 (1uF 250V axial). The only one I have near those specs is a 10uF 250V radial, so I think it's gonna be fine !Last edited by guizmo1967; 10-04-2023, 11:34 AM.
Leave a comment:
-
Re: BK Precision model 1472C Oscilloscope Intensity problem ??
The two neon bulbs (NE-2) N301 and N302 are there for what exactly ??
I'm asking because they barely light up …
Some voltage measurements:
On one side of R349 +195V, the other side with anode of D313, cathode of D314 and collector of Q318 I get +63V.
VR307, C337 and cathode of D313, I get +112V.
In the service manual, collector of Q318 should be +80.6V ???
All the other voltages on that Power Supply are good !!
Leave a comment:
No activity results to display
Show More
Leave a comment: