ACER v243h 2 seconds to black

[thetonywarren]

ive repaired quite a few monitors, but really only the ones that I can physically see that the caps are bulged and need replacement. Beyond that, I am in need of instruction as to how to begin to troubleshoot. I have basic multimeter as well as an esr meter and a Peak DCA55. I am currently working on an acer v243h monitor that looks to be giving me the 2 seconds to black issue. I hear a buzz/whine when I plug it into 120vac and I get the acer splash screen and the "no cable connected" image but then goes black. I dont see any bulging caps, can anyone direct me on what and how to check the various suspect components to repair? I have attached a few pics of the power board and video board.

Thanks!

[Davi.p]

Re: ACER v243h 2 seconds to black

It lacks the results of some test as from the 2 sec. to black sticky guide.. i know it's a long thread, maybe someone can make a summary..

[dj_ricoh]

Re: ACER v243h 2 seconds to black

you need to change the lamps

[selldoor]

Re: ACER v243h 2 seconds to black

If you click on troubleshooting computer displays at the top of the page the guide written by retiredcaps is the first sticky. Most of the tests are in post19 start to read from there.
First thing I usually test is the inverter transformer secondary resistance. These are the two black & yellow rectangular components.
No power to the board set your meter on ohms 2000 and test across pins 7 and 8
(numbered in your picture) on each transformer.

EDIT - As Di Ricoh has just posted on acers if they are used heavily the
lamps seem to wear out as a common failure.

[thetonywarren]

Re: ACER v243h 2 seconds to black

I will definitely go through the sticky, I will need some guidance there on a few tests though. I'll follow up on that. As far as the CCFL's go, is there any way to test them while still in the lcd panel, without tearing the entire LCD panel apart?

[thetonywarren]

Re: ACER v243h 2 seconds to black

as a follow up to the reading on the secondary transformer test points 7 & 8. The resistance is around 664 on one and 658 on the other, I would guess that they are both ok, given the sticky mentions if they are more than 3% difference then it would be bad. Can you confirm?

Thanks!!

[selldoor]

Re: ACER v243h 2 seconds to black

Inverter Transformers are good.

You can test bulbs to see if they are completely broken by plugging one in at a time and see if it flashes. NB ONLY confirms completely broken as against faulty.
You can buy a tester or do you have anything else you can plug them in to test.

A reverse test is if you have a good panel on something that you can plug
into the acer then if that works you know it is the bulb.

Another way is to build a test bulb - 2 is better from a cfl bulb - try and find a post by budm (lots of them) and in his signature there is a link to a guide.

[Davi.p]

Re: ACER v243h 2 seconds to black

or you can disable the protection, usually by putting to gnd an ic pin, if the lamps come one both bottom and top you have some old lamps, then you must dismount panel and see which one has darkened ends, them must be replaced, if one only side comes on you can probably have one half of inverter circuit faulty, so check for power mosfets.. you have to write here the p/n of the bigger ic on the bottom side of psu bd if you want to do this.