Acer AL2423W Recapped, backlight works but no display

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

Got some news
I bought another mainboard on eBay about a year ago, because it had a newer firmware:
The firmware version is actually printed on the back of the PCB on a sticker, this new one was CKS: 7F70 VER: 1.01
It did not fix the "no signal" issue but this one did support HDCP because it uses the Genesis gm5861H-LF processor vs gm5861-LF of the original board...

But then a few weeks ago I saw that a seller was offering the mainboard for a Acer X241W with firmware v1.02 & checksum: 0BEB
Based on the Acer service bulletin above it might still not be the right one, but I had to give it a try
It was installed just yesterday so it will be a long while until I know if it works or not since the issue is so intermittent.
I have attached both firmwares to this post
P.S: The X241W lacks the hardware for the speakers, I might just try to flash the board I bought a year ago and see if it works.
It was anyway time for a recap of it as you can see there is one bulging Teapo, great QC there Teapo: they all invariably fail eventually

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

I have now located another reason for the "no signal" message being shown while the monitor still displays a picture.
It's a firmware issue! See below quote from Acer service bulletin for the Acer X241.
(The X241W monitor is basically the same without adjustable stand and speakers).

I posted a screenshot of how the service menu looked in the first firmware I found way back then.

I did some more searching, and found a user that has uploaded another firmware on a Russian forum since after the first one I found.
The version string shown in the service menu in this version is still v1.00 but it's obviously different because there is a panel selection menu for example.
The first firmware I found did not have that, and it also did not support the actual panel that was installed in my monitor:
A Samsung LTM240M2-L02, which explains the issues I had with color balance after I got it working back then.

To see the firmware version: turn off the monitor with the soft-off button.
Then press Auto and the soft-on button simultaneously.
If successful the power LED should now be amber instead of green.
Next press "menu" and it should say "Factory mode" if it does you press "menu" again and you are in the service menu.
Be careful in here: just take a picture of the service menu calibration values.
Then power off the monitor with the soft-off button.

Then you can dump the current firmware for safe keeping using an external programmer, the chip is U8 on the PCB.
Next flash it with the firmware attached to this post.
I have run mine for 6 months now with this firmware and it seems solid so far
Clarification: the firmware attached to this post is not the same as the Acer service bulletin below references.

DATE: 04/03/08 NUMBER: mn_029

SUBJECT:
REVISED - The message "No Signal" sporadically appears on the screen.

AFFECTS: X241 monitors ET.L990B.029

ISSUE:
This is an update to the document original published 9/19/07
While the X241W monitor is in use, it might show "No Signal" on screen abnormally.
Sometimes, the monitor may still continue to display video.
Other times the monitor may be go black. For some customers, the problem will correct itself in a minute. These problems often occur during the first 20 minutes the monitor is powered on.

SOLUTION:
Short term #1 – Unplug the monitor to reset the video controller.

Long term #1 - The main board firmware can be reflashed to a newer version of
firmware by an Acer authorized monitor repair depot. The latest firmwares are listed below.

for monitor with s/n version “00” and ”10” FW = WDTD-D1AP0 V1.03
for monitor with s/n version “12” FW = WDTD-D1SP0 V1.02
for monitor with s/n version “13” FW = WDTD-D2AP0 V1.03

ACTION REQUIRED:
Confirm the firmware has been updated prior to returning the monitor to the customer
or to stock.
When an Acer service repair technician updates the firmware, they should record that
the part IN-MONITOR was used.

SPECIAL TOOLS
6K.ISPVE.001 Tool Kit with a corresponding DB-15 and Serial data cable.
USB-A to USB-B cable for power.

PARTS REQUIRED
Replace main board if firmware update does not resolve the problem. See spares parts list for p/n.

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

But the original issue with the "No signal" did come up again after a few days.
...
So for the next thing I went back to the main PCB, there where some low capacitance Teapo SH capacitors that I had not replaced.
After disassembly I noticed that there where two different values: 47uF 10v which I did not really have a good substitute for with me.
And 22uF 25v which I decided to replace with 22uF 50v UCC KMG capacitors.
I tested each one on my ESR tester and measured capacitance with my DMM as I desoldered them and got more and more annoyed because they where all measuring good at around 1.0 to 1.5 in ESR!

But finally on the 10:th and last capacitor I found a bad one at 7.4 in ESR!

The monitor once again did the "no signal" problem while still displaying a picture.
So this time I did the last remaining capacitors: the Teapo SH 47uF 10v where replaced with UCC KMG 47uF 25v capacitors.
And it's back to working again!
Now since it's been 7 years since I started this thread maybe I have to start all over again soon

This little monitor just keeps on giving!

...And giving

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

This little monitor just keeps on giving!
After posting the message above that the monitor was working fine even using the same capacitor that Behemot said he had problems with mine developed the same fault!
So I fixed one "no signal" problem where that message would just be displayed while the monitor was still working, only to be replaced by a new one: monitor shut down completely after some time of use!

So I looked at the specs of the startup capacitor and just like Behemot said the one we both used as replacement was quite far off from the original.
So I searched Elfa and found this one which matches the original quite well when you take the ripple frequency in the datasheets into account Elfa partno: 167-04-347
It's a NIC Components NRSZ Series capacitor partno: NRSZ100M50V5X11
It's been working fine since putting that in some weeks ago. (Touch on wood).
Let's see if I broke it again by just saying that!

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

I gave this monitor to my parents years ago, it started developing a problem quite a while ago that I have not taken the time to try and really fix until now:
The monitor would turn on fine from cold but would after being on for some time display a "No Signal" message on the screen even though it was still working fine.
In the very first post I mention this:

(Actually I cheated and did not replace the 10uF CapXon because I had problems removing the grounding shield, also I did not replace the 450v bulk filter cap next to it)

So I thought this would be a good place to start, I replaced the 82uF 450v CapXon KM with a 450v 100uF Nichicon PT capacitor.
And the 10uF 50v CapXon KF I replaced with a United Chemicon KMG 10uF 50v capacitor.
As I was curious to find the actual culprit I did not do anything else with it. (The old caps measured good though).
And only after did I find this quote in another thread:

Which caps would you recommend instead of CapXons KF 10 uF/50V (120 ripple, 2 impedance)? I tried Chemi-Cons KMG, but it was not working (power supply went into safe mode almost directly). Samxon's GK 22 uF worked for ten hours, than I gave it to a guy for long run test and it went into safe mode after 10 minutes. What about GK 10 uF? According to Joe's web, they have 285 ripple, 0,03 ESR.

My monitor did not seem to be worse off with the KMG capacitor though.
But the original issue with the "No signal" did come up again after a few days.
(It was a very rare intermittent problem that I only witnessed myself once or twice)

So for the next thing I went back to the main PCB, there where some low capacitance Teapo SH capacitors that I had not replaced.
After disassembly I noticed that there where two different values: 47uF 10v which I did not really have a good substitute for with me.
And 22uF 25v which I decided to replace with 22uF 50v UCC KMG capacitors.
I tested each one on my ESR tester and measured capacitance with my DMM as I desoldered them and got more and more annoyed because they where all measuring good at around 1.0 to 1.5 in ESR!

But finally on the 10:th and last capacitor I found a bad one at 7.4 in ESR!
It sat right next to the input power pins that connect to the power PCB (old picture here with it in the top left on the green PCB).
Which looking at the markings on the PCB seems to be related to the "ON/OFF" circuit of the monitor, so quite logical after all
This was around a month ago now and the issue has not come back so it seems it was a good fix

[ndugu]

Re: Acer AL2423W Recapped, backlight works but no display

Hello, Per.
All the same I managed to recover the monitor. The last time when the monitor has again refused to work, I has thrown it in a far corner. Then, after a while has decided again it to look. Has checked up an oscillograph all power supplay - all normally. Has then looked Flash-rom - activity on information outputs is watched, i.e. the processor and flash work!

Began to look further, and in at last has found the reason - diode D18 in the voltage regulator on 1.8 volt.
On it too big voltage fell, and this defect was not to constants (that appeared disappeared). Has replaced, flash-rom didn't become flashing, at once has included - the monitor has worked.

Per Hansson, the same adjustments at me too aren't saved, but I any more don't pay attention to it.
Earlier I had a version firmware 1.3, and they be 1.0.

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

Posting an update on this.
The monitor did not fail but it started to behave erratically, would hang on startup with the Acer logo.
Would be impossible to turn off, and other misc problems like that, leaving it unplugged for 10 mins and then starting it always did bring it back tho...

Per the advice of ndugu I bought a new SST25LF040 Flash chip, the seller ecking767 on eBay has them for sale at $10....

So I again desoldered the original SST chip that I had flashed with the Russian firmware
Since I now had something to compare with I could find some things out
Address;
7D384 = settings in service menu for "7500" setting in HEX format
7D387 = settings in service menu for "9300" setting in HEX format

So this confirms that I am using the calibration data from the Russian guys monitor who originally dumped this firmware. (Originally I thought maybe the settings where saved in some other chip...)
I did have a look in the original firmware from my monitor that I had dumped 5 weeks ago before reflashing it. But the flash was corrupted at this address, infact almost the whole flash was corrupted, thousands of lines did not match...

Now the reflashed original SST chip I had been running with up untill today was corrupted after address 7D086, which matches quite well with what ndugu says above aswell...

Sadly the monitor still does not remember the settings changed with this new eeprom in the normal menu system, "warm", "cool" or the RGB values under "user"
It also does not remember the Offset settings in the service menu, but it does remember the 7500 and 9300 settings just like before.
Now since I managed to find these settings in the eeprom it would seem logical that the other settings are stored in some other chip
However that seems contradicting because when I was poking with the monitor before I tried the menu option "auto color" which reset the gain to R:2 G:2 B:2 and And Offset1: R:104 G:124 B:79, which then could not be changed, but it was saved...
However now that I replaced the eeprom these setting where restored to what you can see in the picture posted a few posts back...

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

My monitor has an annoying problem, I can change the values in the service menu, except "Gain" and "Offset1" which I can not move the cursor to
However the option "Offset" can be changed, but it is reset to firmware defaults after a complete powerloss (standby works fine)
The issue is the same for the setting "user" in the normal menu (not service menu) It resets the RGB values to 100/100/100 after a power loss
The monitor does however save most of the other settings, like "7500" and "9300" in the service menu, and contrast/brightness in the user menu, language too (now English)

I have created a thread about calibrating the monitor on this forum here, it was then I ran into this issue...
http://www.avsforum.com/avs-vb/showt...php?p=19048839

ndugu; this retailer sells the logic boards, there is even one that says "HDCP" in the name, they should work since they are listed as spare parts for monitor type Acer AL2423W
Look under the section "main board"
http://www.zandparts.com/acer/index....=3a&language=1

[ndugu]

Re: Acer AL2423W Recapped, backlight works but no display

Yesterday again reflash my chip, at power up - then the screen short-term seemed has gone out, to buttons did not react. Has checked up flash - the code is corrupt after 7D002 address. Has anew programmed, the screen monitor has ceased to switch on, to buttons does not react. Again the code is corrupt after 7D004 address.

It seems that the processor, флэш here not has died and. Indirect tags that the processor unsuccessful it not datasheets on a site of the manufacturer, also are not present support in GPobe.

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

Just managed to get into the service menu, this is what my monitors settings are right now;

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

That is interesting PlainBill
I can't of course know if the settings my monitor now has where saved in nvram in some separate chip on the board
Or if the settings infact are stored in the flash chip I reflashed (I guess it very well could be that way, since the default language became Russian after the flash, and I downloaded the firmware off a Russian board...)

Of course I do now have a backup of my original corrupted firmware too, so if I'm really crazy some day maybe I'll try to find a partition table or something in it with the nvram parameters and try to read what they where

Here are some other fun tidbits from the firmware;

Revision:  1.72
Time=%d.*RSP Auto OK.*RSP Auto Fail.IA

Auto corrupt the firmware when warranty time is out?

V1.72 Beta_01.0525 14:00

Typical Acer QC control^^

16:30:14 Dec 22 2006.AUO_WUXGA_M240UW01_V0.BOARD TYPE: EV_BD.TCLK = %dMHz

AU Optronics MVA panel, very nice panel

HDCP_Init: error reading BKSV.&&&&&&&&&&&&&&&&&TEST0 %x.HDCP_Init: error reading BKSV.aaa.HDCP_Init (gencrypt enabled): NVRAM addr 0x%x.HDCP_Init (gencrypt disabled): NVRAM addr 0x%x.bbb.*************TEST %x.HDCP_Init: gm_ReadNVRAMAbsolute error reading keys

I think this will always fail, because the cheap bastards didn't implement the HDCP cryptographic chip AFAIK!

Also I should add that I replaced the 3x capacitors on the backlight preemptively before I put the monitor back together
They are pictured below, I can't make out the brand name (NK Con?)
They are rated at 180uF and 30v, they are 8mm wide and 9mm tall, I measured them at 0.11ESR and 178>180 microfarad (yes, really!)
The colors are very very close to Sanyo/Suncon, however the bung not so...
I replaced them with Rubycon ZL 220uF 35v caps, they have the same width but are 11.5mm tall, it was a very nice snug fit under the backlights metal cover

[PlainBill]

Re: Acer AL2423W Recapped, backlight works but no display

PlainBill & retiredcaps, thanks for the kind words and encouragement, I hope you have luck fixing your monitor too PlainBill!

ndugu; thank you for the heads up, if my display fails again I'll send you a mail (you could also just subscribe to this thread)

I did reprogram the same flash chip, I did flash erase, erase verify, than flash & verify
Then I disconnected the programmer and reconnected it again, and read the chip, and manually HEX compared it with the file I used to flash... All matched...

The flash chip is for sale here on eBay for example; http://cgi.ebay.com/SST25LF040A-33-4...-/200470003143

Though I do think it is strange the flash chip would be damaged by poor capacitors, so maybe you are correct, it could be some other defect.
Because I found after I had flashed my chip the settings in the monitor seemed to be preserved, so probably the nvram for settings is in one of those EDID chips (24AA02)
(So the question is why the flash becomes corrupt, if the monitor is not writing nvram settings to it that is...)

While it is possible the flash chip was damaged by bad power, the phenomena of the contents becoming by an unstable power supply is well known. Perhaps the most notorious example was several RCA TV chassis with poor solder connections.

As I recall the preferred solution was to repair the solder joints, use the service menu to view the various settings, replace the eeprom, and reenter all the settings.

PlainBill

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

PlainBill & retiredcaps, thanks for the kind words and encouragement, I hope you have luck fixing your monitor too PlainBill!

ndugu; thank you for the heads up, if my display fails again I'll send you a mail (you could also just subscribe to this thread)

I did reprogram the same flash chip, I did flash erase, erase verify, than flash & verify
Then I disconnected the programmer and reconnected it again, and read the chip, and manually HEX compared it with the file I used to flash... All matched...

The flash chip is for sale here on eBay for example; http://cgi.ebay.com/SST25LF040A-33-4...-/200470003143

Though I do think it is strange the flash chip would be damaged by poor capacitors, so maybe you are correct, it could be some other defect.
Because I found after I had flashed my chip the settings in the monitor seemed to be preserved, so probably the nvram for settings is in one of those EDID chips (24AA02)
(So the question is why the flash becomes corrupt, if the monitor is not writing nvram settings to it that is...)

[ndugu]

Re: Acer AL2423W Recapped, backlight works but no display

I congratulate. However take your time to rejoice, in my case breakage has repeated in 1-1,5 months. Tell you has programmed the same Flash chip or new?

It I to that can be because of the bad power supplies Flash chip have acquired some deficiency and in due course the data are distorted. Then would be correct to deliver a new chip.
In my city on sale there is no given chip, therefore I cannot check up my theory.
Please inform me on rus_69@mail.ru if breakage repeats. If will not complicate.

[PlainBill]

Re: Acer AL2423W Recapped, backlight works but no display

That's great news. I've got a Dell monitor around here somewhere with the same symptoms.

PlainBill

[retiredcaps]

Re: Acer AL2423W Recapped, backlight works but no display

IT'S ALIIIIVE!

Soldered the EEPROM back in place and the damn thing booted right up, all seems to be working well!

Congratulations! Well done and great perseverance.

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

IT'S ALIIIIVE!

Hi guys, I'm sooo happy now
Me and a friend tried all day to piggyback my Willem USB programmer ontop of the EEPROM while it was still on the logic board, we even managed to read it about half way or so once
Some more trials of duct tape etc later we where no closer to the solution though...

Anyway, finally he convinced me to take the bull by the horns;
So I desoldered the chip, and then we connected some wires to it and read it with the programmer, turned out the firmware did look corrupt
So next we flashed it with the firmware that I linked to on that Russian board above
Soldered the EEPROM back in place and the damn thing booted right up, all seems to be working well!

There are some Russian error menus on it now but I guess I can live with that, me having such a love for Russian software like nginx and the likes
Also it is always good to know what "no signal" means in Russian
(And after navigating the menus for a while maybe I'll manage to find what "English" means in Russian too )
Thank you allot all who helped me in my trials with this monitor!!!

Btw, I should add that I tested the serial port again, both with Hyperterminal and the gProbe software, however I got nothing at all, so probably some kind of special adapter is needed here...

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

A friend came over with a 10Mhz oscilloscope, we have the same basic understanding of how a scope works; bloody none

Anyway after poking at the buttons and dials for a while we kinda made it make something which almost looked like something
When the monitor is started there is a very small (0.5sec or so) blip on pins #2 & #5, then nothing
And on Pin #6 there does seem to be a signal present... (Pin #6 = "Serial Clock To provide the timing of the serial interface.")
I guess this kinda jives well with the fact that I only got one small blip when I connected up to the serial port of the monitor that I soldered on...
I will try to read the EEPROM with my Willem programmer in some way now, I don't have an adapter that fits but maybe I'll manage to jig something up with a couple of wires and some ducttape

[Per Hansson]

Re: Acer AL2423W Recapped, backlight works but no display

ndugu; Well I don't actually own a Oscilloscope, so therefore I am searching under the lantern light meanwhile
Hopefully a friend will help me out during the weekend...

[ndugu]

Re: Acer AL2423W Recapped, backlight works but no display

Parable:
- What do you search under a lantern?
- The key has lost.
Where you have lost it?
- Yes on that road.
Why here you search?
- Here is more light...