EEVblog Electronics Community Forum

Electronics => Repair => Topic started by: Shirakaba on October 25, 2015, 05:19:07 am

Title: HP L2445w 24" TFT repair
Post by: Shirakaba on October 25, 2015, 05:19:07 am
I have been troubleshooting the SMPS in a dead HP L2445w 23" TFT monitor for the past week. Finally found the culprit, a 0.1nF ceramic disc bypass capacitor on VDD of the SG6902 PFC/Flyback PWM Combination Controller. When the capacitor was removed, the switching returned, so I replaced with a similar one from a SMPS in my scrap bin.

When I got the power back I could see a whole bunch of dead pixel islands in the bottom of the screen. The person I got it from said it was barely used and worked perfectly until it went black, so my guess is that it is due to transport damage. Is there anything that can be done about this kind of damage, or is all hope lost?
Title: Re: HP L2445w 24" TFT repair
Post by: SeanB on October 25, 2015, 06:51:50 am
Nothing you can do, it will eventually enlarge to a black irregular shape in that area, but if you can live with it it will last years still.
Title: Re: HP L2445w 24" TFT repair
Post by: Rasz on October 27, 2015, 06:57:31 am
person that sold it to you might of lied :/

are those blobs static? or do they show up few seconds after powering up?
Title: Re: HP L2445w 24" TFT repair
Post by: crispy_tofu on October 27, 2015, 07:04:09 am
person that sold it to you might of lied :/

Hmmm... I wonder if they had pictures of it working in the listing, unless it wasn't from the Internet  ;D
Title: Re: HP L2445w 24" TFT repair
Post by: Shirakaba on October 27, 2015, 07:17:34 am
It was sold as "not powering on", so there were no pictures of it running. The symptoms pointed in the direction of being an smps issue, which it was (see my first post). I asked the seller specifically if there was anything else wrong with the monitor and he replied it was working perfectly fine until not starting anymore. Of course he could be making it up...  :-//

Quote
are those blobs static? or do they show up few seconds after powering up?

As far as I can tell they are permanent.