Acer P243W A - Help needed

[spintop]

This monitor fails to turn ON at all.
Found the power supply was badly shorted.

- Power supply: 6832194100P01; PTB-1941; 08/07/07
- Shorted MOSFET 13N50C, F11NM80 & SRF20150C
- Burn resistors - 0.33 2W, 0.4 2W

However, this resistor R827 on the back of the PSB was badly burnt beyond recognition. The IC is SG6901ASZ.

I hope someone with the same board could share what value of resistor is it, or a schematics will be even better.

Thanks.

[Redion]

Re: Acer P243W A - Help needed

Hey there

I have a different short. Located at C825 right under connector for the inverter. Doesn't even turns on as well.

R827 - 2701

diagram -

[spintop]

Re: Acer P243W A - Help needed

Hi

Thanks for the schematics.
After replacing all the shorted components, i managed to revive the LCD and i got display. The tough part is sourcing the SMPS IC.

Have you solved your problem?

i still have a problem - the PSU is giving out a loud continuous cracking noise.
the sound disappeared when i increased the brightness to more than 85%.
It seems to be coming from around the big cap100uf 450V and the brigde rectifier. Replacing the big cap and resolder all the inductor and transformer did not solve the issue.

anyone has any suggestions or solutions?

thanks

[Redion]

Re: Acer P243W A - Help needed

Hi good to hear. I fixed mine an hour ago. Now testing it!

the problem on mine was a short. for some reason tracks shorted out and melted together. So i piled some of them off (the part that melted) and PSU started up no problem!

Regarding the noise i just live with it ))))

I also noticed that this particular LCD panel is compatible with some other brands that have the same connector LCD panel connector.
Also the PSU can be replaced with other PSU from different brand. I was gonna replace it with PSU from HP or EPSON printer. Those have +24V and +5.5V so that could of worked if mine didn't started up.

[spintop]

Re: Acer P243W A - Help needed

Thats great.

The noise coming from my LCD is just too unbearable, quite loud too. I will try to replace the Brigde Rectifier if it is not too expensive, hopefully it is the cause. If not i will have to adjust the brightness to 85%, to kill the noise. A very strange phenomenon though.

[Redion]

Re: Acer P243W A - Help needed

Thats great.

The noise coming from my LCD is just too unbearable, quite loud too. I will try to replace the Brigde Rectifier if it is not too expensive, hopefully it is the cause. If not i will have to adjust the brightness to 85%, to kill the noise. A very strange phenomenon though.

can you circle Brigde Rectifier on one of your pics. Thanks

[spintop]

Re: Acer P243W A - Help needed

can you circle Brigde Rectifier on one of your pics. Thanks

Its D802 - Screwed to the biggest heat sink, top left of my pic.
But i am not sure if this one is causing the noise. seems to be coming from there.

How bad is your noise from your LCD?
try to adjust brightness to see if it kills the noise, mine did at 85%

[Redion]

Re: Acer P243W A - Help needed

How bad is your noise from your LCD?
try to adjust brightness to see if it kills the noise, mine did at 85%

Its not bad, very high pitch sound. I have other monitors that make noise.

I don't remember diode bridge making noise ever. Wired

[spintop]

Re: Acer P243W A - Help needed

Its not bad, very high pitch sound. I have other monitors that make noise.

I don't remember diode bridge making noise ever. Wired

Maybe not, or it could be coming from the 3 coils around the same areas.

[spintop]

Re: Acer P243W A - Help needed

Finally isolated the noise to come from L801 and the 2 cap besides it, C855, C856. After removing the 2 caps, the noise was greatly reduced, though still some humming from L801 but its rather faint sound.

I believe these 3 parts are for filtering right after the rectifier. Though without the caps the LCD still works, they are there to clean up unwanted high freq in the power line.

Its now easier to just figure out if the fault is in L801 or the caps

[capsn]

Re: Acer P243W A - Help needed

Finally isolated the noise to come from L801 and the 2 cap besides it, C855, C856. After removing the 2 caps, the noise was greatly reduced, though still some humming from L801 but its rather faint sound.

Its now easier to just figure out if the fault is in L801 or the caps

thx for the info.
Did you manage to further isolate or fix the noise on that power supply ?

got me a cheap second hand unit of this monitor p243w.
i do have the humming noise as soon as the power cord is plugged in (monitor off) and would like to fix it, i expect it to be some coil in the rectifier area, i usually glue them to death.

[spintop]

Re: Acer P243W A - Help needed

thx for the info.
Did you manage to further isolate or fix the noise on that power supply ?

got me a cheap second hand unit of this monitor p243w.
i do have the humming noise as soon as the power cord is plugged in (monitor off) and would like to fix it, i expect it to be some coil in the rectifier area, i usually glue them to death.

I bought 2 new caps to replace them, didnt solve the problem. I removed the 2 big caps, the humming noise reduces greatly. It is now running without the caps, and I don't see any impact to the video quality. Well i think that will depend on your power lines quality in your country.

Hope it helps you. Let me know if you found out more.

[capsn]

Re: Acer P243W A - Help needed

thx for the quick reply.

those two big caps still being C855, C856 next to L801 right ?

did you try to further glue that L801 coil ?

i would assume that those caps have an impact on the coil behavior so removing them would change the noise emitted. Or maybe the coil being glued to the caps, as shown on your picture, makes things worse.

I haven't disassembled the monitor yet, i'm browsing the web prior to doing anything.
I'll try to take a look at it over the weekend and get back to this thread when i've done something.
I usually plug the power board without anything connected to it and push (not bare hand) on the various coils, transformers or capacitors, until i hear something different, then i drown it in glue.

A last quick question, did you hear the noise when the monitor is switched off but powered.
It's louder when the monitor is switched off but i can still hear it when it's on, the pitch is also different i believe.

[spintop]

Re: Acer P243W A - Help needed

yes the 2 big brown cap - u can try remove them and see if the noise is reduced.
I poured glue - but no improvement. pushing all the parts still cannot isolate the issue.

Good luck !