ACER GD235HZ - Won't turn on

[G2idlock]

So it's come time for me to learn a couple things.

I have this oldie but goldie monitor that i want to get running again, it's been 2ce so far this monitor went out cold on me. First time was around 8 months ago when i had a power outage and the screen would not turn on. Took it to get it fixed, it stayed there for 3 days and came back alive and working. Not 40 days later, another power outage and my screen went dark again (Yes, I've learned, I now have all my current components plugged into a surge protector). It's been dead since (about 6 months now).

Here's the issue in a single sentence:
- Plugged in.
- No lights, no backlight, nothing. Completely dark.

Now I'm not about to drop another $150 to get this fixed again, if it's going to come back to life, it's going to be by my hands. BUT, I don't know how.

I found a thread on here, pretty dead since 2016, where the person involved had a very similar problem but I have no clue what was fixed, how it was fixed.

https://www.badcaps.net/forum/showthread.php?t=55249

At this point I have the necessary tools to diagnose the problem, but 0 knowledge on how to do it.

Any guidance would be greatly valued.

Thank you!
Andrew.

[G2idlock]

Re: ACER GD235HZ - Won't turn on

Wouldn't let me edit my original post. Adding pictures of PS and main board.

[G2idlock]

Re: ACER GD235HZ - Won't turn on

So, I took a gander with my lack of knowledge. Checked the PSU and was getting 5v off of both pins to the mainboard...

So It's come down to the main board.

Anyone have an idea where I should check first?

I'll keep doing research, haven't found any documented guide / video or schematics of the board, so I'm a bit overwhelmed.

the 5v pins on the PSU go into the main board on the red and orange wires on the front facing top left connector of the main board.


EDIT: Following Budm's advice on the other post. Don't know how to check DCV on the board, but am checking the I202 and I203 Inverters???

[G2idlock]

Re: ACER GD235HZ - Won't turn on

I'm stumped I've reached the ever so slowly extending cap of my knowledge. As in the other post I checked the I202 and I203 (Not inverters, linear regulators) on the logic board.

I202 and I203 are CMOS LODs Type AME8815BECSxxx

http://www.ame.com.tw/datasheet/AME8815.pdf

The diagram on the schematics shows me that pin 1 is ground, 2 out and 3 in. I'm using my $8 multimeter on diode testing ( ->|- ) mode to check if they work... But, color me stupid, I clearly don't know how to do this. I've tried red lead on 3, and black lead on 2 in I202 and get a increasing reading that caps out at 1850, then I switch black lead to 1 and get same number. On I203 same methodology but get 862 on pins 3&2 and 1850 on pins 3&1.

What?

What does this mean?

[CapLeaker]

Re: ACER GD235HZ - Won't turn on

5 VDC STBY on the PSU should be always on and goes to the main board. From there, when you press the power button, the main board should turn on the PSU (PSon) and the inverter (BLon). You should see somewhere between 2 VDC and 5 VDC on one or two of the pins on the returning to the PSU, in order for the PSU to turn on all power rails and the inverter. If there is only 5 VDC going into the main board and nothing coming back out from the main board to the PSU, the main board is toast. My best guess it would be then the main IC on the main board. Either it is bad, or it is a BGA issue.
If you can figure out on the PSU what pins are PSon and BLon, you can force the PSU on yourself with out the main board by using two 1k resistors and jumping STBY to PSon and BLon and plug the PSU in. Once plugged in, the backlights should be on and all power rails on the PSU should be on too.

PS: get a better DMM too while you're at it.

[televizora]

Re: ACER GD235HZ - Won't turn on

Heat the caps. Try to turn it on then. Measure for short between the legs of the diodes and transistors. Any suspicious so noises coming from the PSU?
Disconnect the lamps and try to turn it on. Usually it's either the caps or short diode. Or rarely the voltage regulator for the MC on the control board.
If it's neither of these, I'm not sure that you can fix it. Usually it's the caps. When they are heated with a hair dryer, the capacity goes up and the ESR down. And it turns on till the next time. If this is the case, you can fix it for 5$
It's a CCFL monitor. Soon the CFLs will die. You will need to replace with new or put led stripes.

[stratcat]

Re: ACER GD235HZ - Won't turn on

Hi,

I had the exact same issue but it wasn't due to a power outage. No power, no light. If I unplugged it from the wall it wouldn't come back on. The first time I let it sit for 3 weeks, tried it again and viola the light came on and the monitor worked for 3 months until I had to pull the power one day and it never turned on again...

I started investigating and found a short to ground on pin 6 of I207 which led me to the BGA chip. I wound up re-flowing the BGA chip and it's now working again.

I used the schematic linked in this thread to check voltages which was a big help (thanks to lepak06). It seems the 235hz and 245hq share a lot in common - https://www.badcaps.net/forum/showth...highlight=acer

Good luck!