Acer AL1917 restarting

[Rtech]

Re: Acer AL1917 restarting

Chances are it is them.

[Behemot]

Re: Acer AL1917 restarting

Those DIP-8 chips? They're actually the lately comon two-transistors-in-one-package? I haven't checked them, thought they are some drivers actually

[Rtech]

Re: Acer AL1917 restarting

The two Mosfets fail regularly on DAC Boards,and thats probably the problem.

[Behemot]

Re: Acer AL1917 restarting

Here are the images finaly, if you can advice comething from it, would be cool

ATM, there are some caps recapped, some original as I tried if the problem is not in in too low ESR of replacements and so

[Behemot]

Re: Acer AL1917 restarting

Tried CCFL from the other display, still restarting, seems that problem is in the inverter itself.

Will ask friend of mine for camera, I left mine at home and as you see withotu camera it would be difficult to take pictures

[Behemot]

Re: Acer AL1917 restarting

I told ya I cannot do it right now, wait a while, OK? If it is supposed to be any good, I need room, time and equipment for that. I do not have any right now, there are computer parts everywhere and I need to finish this first.

[retiredcaps]

Re: Acer AL1917 restarting

Yep, AL1917 C (line below it says: Version: 1917 Cs). Can they change whole interior with new revision??

Yes, that is why we always ask for pictures.

[Behemot]

Re: Acer AL1917 restarting

Yep, AL1917 C (line below it says: Version: 1917 Cs). Can they change whole interior with new revision??

[budm]

Re: Acer AL1917 restarting

Are you sure this is AL1917? Those 4 tiny transformers are the high voltage balancers for lamps.

[ben7]

Re: Acer AL1917 restarting

Even though there are two transformers in invertor, there is only one tube. At least I believe so. THe thing is, there are another four tiny transformers with CCFL-like connector, and I don't have any idea where it is attached to…

Didn't check transistors but I think if they were bad (short), it would restart/go to protect mode immediatelly, no? They are before the transformers thus still under voltage from the power supply part.

One could be open circuit.

There must be more than one ccfl in this thing.

Could be get some pictures?

[Behemot]

Re: Acer AL1917 restarting

Even though there are two transformers in invertor, there is only one tube. At least I believe so. THe thing is, there are another four tiny transformers with CCFL-like connector, and I don't have any idea where it is attached to…

Didn't check transistors but I think if they were bad (short), it would restart/go to protect mode immediatelly, no? They are before the transformers thus still under voltage from the power supply part.

[ben7]

Re: Acer AL1917 restarting

Check the MOSFETs that drive the transformers.

Is it happening with only one ccfl? or both?

Try changing the startup capacitor too

[Behemot]

Re: Acer AL1917 restarting

Yeeah I checked for cold joints right away, didn't see anything bad. Seems that Delta made good work in soldering.

[ben7]

Re: Acer AL1917 restarting

Check to see if there are any pinched HV wires. Also check for bad solder joints!

[Behemot]

Re: Acer AL1917 restarting

Not even close…gimme some time, I have to finish some reviews and computer builds, than I will return to this again

[budm]

Re: Acer AL1917 restarting

Does your board look like this?
http://lcdalternatives.com/Repair-Ki...-P2060847.aspx
It sure does not sound like what you have, the AL1917.
Can we see the pictures?

[Behemot]

Re: Acer AL1917 restarting

24 V without load, than it drops down to 22 V or so.

It has 5 V, 13,8 V for data/audio board, another separate 16-17 V rail and this 22 V for inverter. Most likely for better efficiency. Delta board.

[budm]

Re: Acer AL1917 restarting

"Changing all the caps on inverter power supply (various 25V caps, there is up to 24 V on it)" If it really has 24VDC on them, that is way too high for 19" monitor, typical 19" will use 14~18VDC for running the inverter circuits.
You can also use this for testing inverter circuits.
http://s807.photobucket.com/albums/y...g%20old%20CFL/

[Behemot]

Re: Acer AL1917 restarting

Well U usually resell whole display if electronics is bad, never encountered bad CCFLs so far.

[senndogg]

Re: Acer AL1917 restarting

yes, you can use them from a second monitor.
if you think you will be repairing more and more monitors, you have to collect several ccfls (of different sizes). they will be handy!