I get the second flash to black issue on these mostly.
These are all Acer model V173 monitors. They all basically do the same thing, or I can't recall but a few might not power up at all. If important I can plug each of them in again and double check.
On the two that I've been focusing on, they do the same thing. One had one clearly going bad cap, the other one's power board looked totally fine. I replaced all but the two smallest on the board that had the one bad one on it. And on the other I did the one big cap anyway. (I then tested the removed cap that looked fine on the 2nd board with cap function on a matco meter I have and it was actually fine.)
Doing any of the caps has made no difference. I removed the two smallest from one of the boards, the only two I didn't do on the one board that I did all the others, and I tested them with the cap function and they were good too. So I have one board that has been mostly recapped and the ones I didn't replace test good when removed. (So basically, all caps on both boards are either new, or verified good.)
When turned on, if not connected to a VGA source, they will come on with the ACER logo fine, lamps light right up, and then show a "no signal" box. Then go dark. The light goes from blue to amber at this point.
If connected to a source when turned on, or simply connected to a source after turned on, the light will go blue, but nothing will come up on screen. If the VGA is then disconnected from the computer, it will again light up and show the "no signal" box, then go dark again. And by dark, the back lights are off.
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.
I'm stumped on these. Usually I can do re-caps but these seem to be a different animal. I have also tried swapping out the ccfls one at a time from other monitors and a laptop monitor. Pretty much same behavior, also visually inspected bulbs and they look 100% good on the ends. Also, obviously capable of staying on since they can display the 98 system usually, they just don't seem to want to stay on for some odd reason on anything else.
(BTW, behavior is the same whether I have the actual LCD panel connected to the VGA board via the ribbon cable or not)
I don't know how to check much else but I did check a few other things,
Each of these I put black lead on fat tab, and the readings are left to right as if fat tab is up.
(numbers on these two components U501 & U502 are; Nikos P2504BDG QN19K0501)
U502 (transistor?) - (not lit) 16.7v / 0 / 16.7 : (lit) 5.7 / 0 / 7
U501 (transistor?) - (not lit) 0 / 0 / 0 : (lit) 5.34 / 0 / 7.09
U101 (on VGA board, looks like 1117 series 3.3V) lit or not lit same = 3.2 / 0 / 1.8
There are three other "IC" (I think they are?) on the board.
(IC803)
A1
AS431A
A0814
(Q801)
C1815
GR8E
(IC801)
0823
817B
I also have two other Acer monitors, AL1706b, one dead as a doornail, and the other comes on sometimes and will display but has wavy picture. I will save those for after these I suppose, thought it worth mentioning though because they have very similar power boards, and also did not physically appear to have any caps bad, but still don't work right.
Any and all help much appreciated. I was tempted to just recycle these and say screw it, opting to fix only easily cap replaced ones, but I've spent the last two days trying to fiddle with these already and trying to learn about voltage regulators and such so at this point I'm not prone to giving up on them until I figure it out! But I fear I will never get there without the knowledge of others. I will try to post a few pics of the boards.
These are all Acer model V173 monitors. They all basically do the same thing, or I can't recall but a few might not power up at all. If important I can plug each of them in again and double check.
On the two that I've been focusing on, they do the same thing. One had one clearly going bad cap, the other one's power board looked totally fine. I replaced all but the two smallest on the board that had the one bad one on it. And on the other I did the one big cap anyway. (I then tested the removed cap that looked fine on the 2nd board with cap function on a matco meter I have and it was actually fine.)
Doing any of the caps has made no difference. I removed the two smallest from one of the boards, the only two I didn't do on the one board that I did all the others, and I tested them with the cap function and they were good too. So I have one board that has been mostly recapped and the ones I didn't replace test good when removed. (So basically, all caps on both boards are either new, or verified good.)
When turned on, if not connected to a VGA source, they will come on with the ACER logo fine, lamps light right up, and then show a "no signal" box. Then go dark. The light goes from blue to amber at this point.
If connected to a source when turned on, or simply connected to a source after turned on, the light will go blue, but nothing will come up on screen. If the VGA is then disconnected from the computer, it will again light up and show the "no signal" box, then go dark again. And by dark, the back lights are off.
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.
I'm stumped on these. Usually I can do re-caps but these seem to be a different animal. I have also tried swapping out the ccfls one at a time from other monitors and a laptop monitor. Pretty much same behavior, also visually inspected bulbs and they look 100% good on the ends. Also, obviously capable of staying on since they can display the 98 system usually, they just don't seem to want to stay on for some odd reason on anything else.
(BTW, behavior is the same whether I have the actual LCD panel connected to the VGA board via the ribbon cable or not)
I don't know how to check much else but I did check a few other things,
Each of these I put black lead on fat tab, and the readings are left to right as if fat tab is up.
(numbers on these two components U501 & U502 are; Nikos P2504BDG QN19K0501)
U502 (transistor?) - (not lit) 16.7v / 0 / 16.7 : (lit) 5.7 / 0 / 7
U501 (transistor?) - (not lit) 0 / 0 / 0 : (lit) 5.34 / 0 / 7.09
U101 (on VGA board, looks like 1117 series 3.3V) lit or not lit same = 3.2 / 0 / 1.8
There are three other "IC" (I think they are?) on the board.
(IC803)
A1
AS431A
A0814
(Q801)
C1815
GR8E
(IC801)
0823
817B
I also have two other Acer monitors, AL1706b, one dead as a doornail, and the other comes on sometimes and will display but has wavy picture. I will save those for after these I suppose, thought it worth mentioning though because they have very similar power boards, and also did not physically appear to have any caps bad, but still don't work right.
Any and all help much appreciated. I was tempted to just recycle these and say screw it, opting to fix only easily cap replaced ones, but I've spent the last two days trying to fiddle with these already and trying to learn about voltage regulators and such so at this point I'm not prone to giving up on them until I figure it out! But I fear I will never get there without the knowledge of others. I will try to post a few pics of the boards.
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