Asus VW246H will not power on

[swofra]

Re: Asus VW246H will not power on

It did for a while but now it does not. Regardless, Anytime it was on it was the same all white screen

[budm]

Re: Asus VW246H will not power on

So LCD screen connected or not you see the same all white screen, correct? If that is the case, the integrated T-CON on the LCD panel may be be getting the Voltage for Logic board to run.
https://www.badcaps.net/forum/attach...6&d=1577135961
Do you see the Triangle marking on the LVDS connector for pin 1 marking? Check that pin when turn on the monitor to see if what DCV you have on that pin.

[swofra]

Re: Asus VW246H will not power on

5VDC showing at pin 1 on LVDS - with and without the ribbon cable attached to monitor and with the monitor attached to computer. Screen still full white. Power comes on and stay on.

[swofra]

Re: Asus VW246H will not power on

so if showing steady 5v at pin 1, is there anything else circuitboard based / other voltages it could be?

[swofra]

Re: Asus VW246H will not power on

Does anybody have ideas on what could be wrong or what the next step should be? Thank you, any assistance is much appreciated.

[jpbnd]

Re: Asus VW246H will not power on

Hello Guys from Germany! I have the problem that my VW246H will not power on. I used a hair dryer to heat it up a little but and it worked! Afterwards it put outside (0° degrees) for 20 minutes and then it didn't work. If I understood correctly correctly this means there is a cold solder joint on the boards.

To locate the part where the heat has an effect I decided to heat the parts separately (Plate with buttons, main board, power supply). The procedure was to remove one item, heat it up, install it and try it again. It came out that when I heat up the main board the everything worked again. Due to that I would say there is a cold solder point on the main board. I checked the board visually, but I cannot identify anything "abnormal" (To be honest I am noob).

Do you agree that it must be cold solder joint or could also be something different? Would it make sense to renew all the solder joints on the backside of the MB?

Regards
Jan

[jpbnd]

Re: Asus VW246H will not power on

Sorry for my bad grammar. I wanted to correct some mistakes, but I cannot edit. :-)

[momaka]

Re: Asus VW246H will not power on

Hi Jan and welcome to the forums!

It came out that when I heat up the main board the everything worked again. Due to that I would say there is a cold solder point on the main board. I checked the board visually, but I cannot identify anything "abnormal" (To be honest I am noob).

Do you agree that it must be cold solder joint or could also be something different?

It could be a colder solder joint, indeed. However, I am more inclined to think the issue is related to bad electrolytic capacitors. In particular, I see what appears to be two voltage regulators at the upper-right corner of the board shown in this picture:
https://www.badcaps.net/forum/attach...1&d=1610274625
If you look carefully, you can see that the PCB around and under them has become darker, likely due to the regulators running hot. This doesn't mean the regulators are bad. Linear regulators do tend to run hot, so this could be normal. However, the heat from these regulators can (and often does) make cheaper / inferior quality electrolytic caps go bad over time.

The two small green caps (looks like Lelon or Ltec brand) close to those regulators likely filter power from the regulators. So my suggestion is to start by removing those two capacitors and checking their ESR - if you have a capacitor meter, that is. If not, just replace them. While at it, you may also want to replace the other electrolytic caps on the logic board too, as they could be starting to fail too.

When replacing electrolytic capacitors, make sure to use a good quality brand and low impedance / ESR. For an application like this on the logic board, ESR/impedance is not too important, so anything from "entry-level" to "very low" ESR should be OK.

Here is a list of capacitors suitable for power supplies and generally all monitor applications:
Manufacturer................................Series
Nichicon ................................ PW, PM, PS, PJ, PV, HE, HD, HV, HW
United Chemicon (UCC) ............ KY, KYA, KYB, KZE, LXV, LXY, LXZ, KZH, KZN
Panasonic .............................. FC, FK, FR, FM, FS
Rubycon ................................ YXJ, YXG, YXF, YXM, ZL, ZLJ, ZLK, LZQ

Last but not least, post a picture of your power supply board, if possible.
Even if the power supply board is not causing a problem at this point, chances are it probably has cheap electrolytic cap brands on it as well (not all monitors come with cheap caps, but many do.) Thus, if you are buying caps for the main/logic board already, the cost of getting a few more caps for the power supply may be worthwhile guarantee that you won't have any problems there down the road too.