Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

[1fg52]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

I have another faulty V173 showing Acer logo. Is like the MCU find every VGA signal as incomplete and went to a "parking" mode turning off backlights. I dissasembled the panel to see if there is an image without backlight but the LCD appears turned off completely.

I found a Service manual for a very similar monitor (same control board) and there is no hope: "No Image" troubleshooting end very fast with "change scaler and mcu" RTD2120L and RTD2025

https://www.manualslib.com/manual/23...page=35#manual

This fault is so pervasive and have same symptomps clearly these realtek chips had a point of failure.

[svagi]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

Hi, I have very similar symptoms on my Acer v173. When without signal is showing ACER logo and after that "no signal" information. When I connect VGA cable from the laptop it stays in the black screen with blue LED on, or the monitor is resetting with approx 3-4 s orange LED to blue LED light. I tested also BIOS mode for lower resolution but this no helped.

[budm]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

But does not make any senses since the backlights are just the light source it could not careless if the monitor is connected the PC with 98 640 res or not. It sounds like the provided DATA is wrong.
Post#1:
"The curious exception to this, is if I connect one to a Windows 98 system set to 640x480 display. They will usually display this. Not always but usually. I can disconnect and reconnect the VGA and it will usually come up and display and stay on. Not always, usually. I've gotten one to display an XP system and stay on once, and flash quickly a few times, but almost always it does nothing."

[Aeridyne]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

Well, in conclusion here, it seems the issue was actually the backlights all along. If I took good working backlights from other stuff and plugged them in to either of the test boards I had they would stay on. Not having any way to purchase backlights for them all I gave up actually repairing them, but I feel I did figure out the real problem.

[kc8adu]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

nailed it.if you have one that works 100% clone eeprom.

Hi Aeridyne, i suggest you to find the program Moninfo from EnTech Taiwan, use it on a pc with first a good monitor, to be able to open the prog., then attach a faulty one and do a grab command to the prog, so it reads EDID data from the monitors, i suspect that those series of monitors has edid eeproms prone to fail.. find the way you want to pubblish the result screens of the prog, so we can see them. Try with all the monitors you have if you want, especially if you see garbled / suspecting data..

[Aeridyne]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

I will try those three suggestions and post back soon. Knee deep in a home movie project for someone atm.

[Davi.p]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

Hi Aeridyne, i suggest you to find the program Moninfo from EnTech Taiwan, use it on a pc with first a good monitor, to be able to open the prog., then attach a faulty one and do a grab command to the prog, so it reads EDID data from the monitors, i suspect that those series of monitors has edid eeproms prone to fail.. find the way you want to pubblish the result screens of the prog, so we can see them. Try with all the monitors you have if you want, especially if you see garbled / suspecting data..

[budm]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

Did you try heating the main/logic board with hair dryer for 2~3 minutes first and then power it up to see what happen, and also cooling it using canned air duster upside down?
BTW, since the monitor has VGA and DVI, when try using either of them, it does the same problem?

[Aeridyne]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

Ok. Not sure how to go further in depth myself. That V reg was as far as I had gotten.

[budm]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

Yes, it is good and the output is within spec. More in-depth troubleshooting of the main board is required. may have corrupt firmware, etc.

[Aeridyne]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

It seems to be working. Measuring with orientation as the fat tab north & the black lead on the left leg (ground), the right most tab shows 4.97V and the center pin and the fat tab / output both show 3.27V

[Aeridyne]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

sorry, I don't know how to delete, I refreshed the page multiple times but I didn't see your reply until I had posted, I will check it according to the new information you have provided.

[budm]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

U101 is
A1
AS1117L-33
B0815 D1

it measures, with black lead on top "fat" tab, from left to right
3.2V / 0 / 1.8

FAT TAB is not GND, that fat tab and the center pin are connected together internally and they are OUTPUT pin.
You need to use circuit GND such as GND pin of the connector.
It is 3.3V fixed LDO regulator 1117 series IC, so if you look at the device with the tab up: Left pin is GND, Center pin is OUTPUT (should show 3.3 VDC), Right pin is INPUT (should show 5 Vdc)

[Aeridyne]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

U101 is
A1
AS1117L-33
B0815 D1

it measures, with black lead on top "fat" tab, from left to right
3.2V / 0 / 1.8

[budm]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

I see one regulator IC U101 on that main/logic board. What is the P/N on it and what DCV do you get on all 3 pins with ref to GND.
You can also try heating up that main board with hair dryer for a 22-3 minutes and then power up the monitor with running PC to see what happen.

[budm]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

Well, no BL-ON = No Backlights. That signal is generated by the main/logic board so main board troubleshooting will be next to find out why.

[Aeridyne]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

Its being a punk and won't display on the 98 system at the moment either, goes right back to black after 5 attempts to turn off/on. I can catch it while the lights are on briefly though and pin 5 shows 3V at that time.

[Aeridyne]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

thanks Budm, I didn't even noticed that the power output from the power/inverter board to the vga board was labeled! Good eye!

Ok so the Pin 1 & 2 says 5V and they look good. Pin 6 looks reasonable and the pin 5 / BL-ON pin has nothing, the power led is blue, back lights are off.

pin 1 4.9
pin 2 4.9

pin 5 (bl-on) 0
pin 6 (brightness) 2.67

[jiroy]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

Thanks for the replies, I've checked the refresh rate and it does not seem to matter what it is set to. These monitors are not ancient, they are LCDs from about 08 and capable of max resolution 1280x1024 I believe, they should display just fine on a wide range of systems just like any other would. Win 7 auto adjusts to the display. I've had them hooked up to 4 different systems and the only one that will display is the 640 res most of the time, not always, sometimes have to turn it off and on to get that to display. And I feel that is a fluke and circumventing whatever the issue is. I can only access the menu when it is displaying the 640 system, no other time. I navigated the menu and "reset" but it made no difference. Something is broken on them, the other ones I had that did work that I no longer have would display Win 7 no problem at high resolutions. I would get one out at random, if it didn't work hooked up to the 7 system I set it aside and grabbed another one until I found one that worked, it was about every other, now I just have the ones that didn't work left. So I don't think its a matter of monkeying with settings or that they are old and need certain refresh etc, they are busted somehow. I just need to figure out exactly what and how to fix it. I know they aren't working right.

Budm - How do I check for BL-ON signal? Resolution set to 1024x768 @ 75Hz when connected to working monitor to check on the 7 system. Also tried 1024 @ 60Hz and made no difference.

I did such procedure some hundreds of times .. It shows on the windows 98 640*480 cause it's a low resolution available in any monitor or LCD . We may even call it a basic display .
Some types of LCDs only need to boot a computer , and then off and on them like three times and they'll catch the resolution and ignite the signal . Others need to press F8 while booting while screen is black , or shut down the computer repeatedly to force him go to safe mode ..

Tempering with probable good screens with some capacitors waking up after a long sleep needs a little patience ..The rest is up to you .

[budm]

Re: Six Acer V173 LCD monitor all with same problem, only display Win 98 640res

https://www.badcaps.net/forum/attach...2&d=1484673696
Power supply/Inverter board:
Pin 5: on/off = BL-ON. <1 VDC = Backlights OFF, >2.5 VDC = Backlights ON.
Pin 6: Brightness = Dim control signal.
So you should check the Voltages of all the pins (except GND) when you do have backlights and pictures on the screen and when you do not (but Blue Power is still on solid).