P2317H not turning on

[questore]

Re: P2317H not turning on

After ESR meter is arriving I think i will try with this to solve the problem:
https://www.youtube.com/watch?v=4HFHpzSQfj0

[questore]

Re: P2317H not turning on

Got a new powerboard and it powers up fine, BUT...
The picture on the panel is scrambled
Plugged back and original panel picture and it fine with my board, so my LCD panel is bad also.
Removed the panel back tape and LCD panel number is:
M230F07V01_HF REV 0.0
- Checked that board and no short to ground
- No bad diode found
- Fuse is ok
Anyone can help diagnosing if it can be repaired?

2 IC THAT IS on the board is sm4142 and lfm60a3
reading after powered on:
VON: 27,9V
VSS1: 8,4 V
VSS2: 9,8 V
TVDD18: 1.8V
TVDD12: 1.2V
DVDD: 1,8 V
AVDD: 10,42
VCC: 5.08V
D2P1 0,58 V
D2N1 0,58 V
HCT3 4,17 V
VCST_S3 4,06 V
CN3R_1 0,020mV
CN3R_2 0,020V
SCL: 5V
RVC 4,6v
CVC 1.03V
R1 0.262
RDV1 10V
RDV2 4V
CREF 4V

[questore]

Re: P2317H not turning on

After hooking up the powersupply to the 5v with the main boards connected and plugged in, the voltage is still waving and goes up only to about 2.9v, maybe the two small electrolit capacitors on the mainboard are bad and cannot hold charge? Ordered an ESR meter for that (will be good for other things as well)
Let you know when power supply board changed and what ESR meter sees.

[questore]

Re: P2317H not turning on

It could be flashing for many reasons, no input signal, no backlights etc.
>Goto #6

I have to wait for a few days before i get the working power supply. In the meantime i was thinking. What if i test our theory by doing the following.
Connect the two boards and also connect my lab power supply to 5v line where its low and let it draw the power from there when its plugged?
I think it could provide a solution for our theory does it not?

[R_J]

Re: P2317H not turning on

It could be flashing for many reasons, no input signal, no backlights etc.
>Goto #6

[questore]

Re: P2317H not turning on

Yes, you can do that or you could load the 5v line on the power supply with something like a 10Ω for about 500ma draw or a 4.7Ω 5watt to draw 1 amp.

Disconnected the two board and hooked a lab power supply on the.5v. input.
Pushed 5.1v and it started drawing 0.020A and the power led started flashing. Maybe its flashing because the rest of the connection pins missing but since 0.020 is small amount, i would suspect the problem is the power supply board. Feel free for dicussion..

[R_J]

Re: P2317H not turning on

Or i can hook up a lab power supply to see if it is drawing power of 5v fine.

Yes, you can do that or you could load the 5v line on the power supply with something like a 10Ω for about 500ma draw or a 4.7Ω 5watt to draw 1 amp.

[questore]

Re: P2317H not turning on

Or i can hook up a lab power supply to see if it is drawing power of 5v fine.

[R_J]

Re: P2317H not turning on

So it is not the diode causing the voltage to drop, It is one of two things, either the power supply can not supply enough current for the main board or something else on the main board is loading down the 5v. The easiest way would be to try that other power supply board.

[questore]

Re: P2317H not turning on

Sorry I misunderstood, I thought the 5 volts was present and only dropped when the power button was pressed. Replacing the diode should resolve the problem.
If the diode is across the 5 volt input to the main board the diode is likely only for protection If the main board is removed and the 5 volts is not high, you can remove it to test the operation of the monitor, after testing install a new 5.6v zener diode.

Removed the bad diode, no change
Any idea?

[R_J]

Re: P2317H not turning on

This is not my problem? I don't understand! Are you meaning changing the bad diode won't fix my standby 5V being 1.2V?

Sorry I misunderstood, I thought the 5 volts was present and only dropped when the power button was pressed. Replacing the diode should resolve the problem.
If the diode is across the 5 volt input to the main board the diode is likely only for protection If the main board is removed and the 5 volts is not high, you can remove it to test the operation of the monitor, after testing install a new 5.6v zener diode.

[questore]

Re: P2317H not turning on

That diode is a 5.6 volt 200mw zener diode, they can be found everywhere, Check the voltage across it. If it is across the 5 volt input, it is good, and this is not your problem.

This is not my problem? I don't understand! Are you meaning changing the bad diode won't fix my standby 5V being 1.2V?

[sam_sam_sam]

Re: P2317H not turning on

I cannot find component, since these are only comes with a package of 3000pcs and this is more costly then buying a new board.

Any replacement suggestions?

Here try this place for them this is the actual part number “ UDZ5V6B-7 ”

https://www.questcomp.com/part/4/udz...ign=partsearch

Here is the data sheet

https://cdn.badcaps-static.com/pdfs/...5bde1316c9.pdf

I have personally ordered from them in the past several times when I am finding hard to find parts yes they do have a minimum amount for an order

[R_J]

Re: P2317H not turning on

That diode is a 5.6 volt 200mw zener diode, they can be found everywhere, Check the voltage across it. If it is across the 5 volt input, it is good, and this is not your problem.

[questore]

Re: P2317H not turning on

I cannot find component, since these are only comes with a package of 3000pcs and this is more costly then buying a new board.

Any replacement suggestions?

[questore]

Re: P2317H not turning on

I had time while waiting for the power supply.
So i have checked every component on the logic board and found a bad diode that reads 0.5v and 0.3v in both ways on diode mode.
I assume its fault can be the cause of the low power since its directly connected on the input rail of the board.
According to the internet it is a "UDZ5V6B" SOD-323 diode.
Attached an image (its the one with the mark of BC), please correct me if I'm wrong.

[questore]

Re: P2317H not turning on

In the meantime i have checked.power board and the 5.12v is present in the other side of the 360kohm resistor, so I wonder...isn't it means that the power board is ok?

[questore]

Re: P2317H not turning on

I think I can borrow another same type power supply to test that theory.
Thanks, I will get back to you with the result.

[R_J]

Re: P2317H not turning on

Your problem is likely with the power supply not the main board, the power supply can't supply any current on the 5v standby line.
I would suspect the small electrolytic (PT504?) in the primary for the vcc line of the controller ic.

[questore]

Re: P2317H not turning on

After letting is rest 24 hours unplugged. The following changed:
The LX has only 0.28v
Also cheched power button line and seems to have no broken resistor and when button pressed, the voltage drop reaches the main IC.
Any idea why 5v not raising after button press?