LCD monitor troubleshoot (flatron LG W2246) - Page 1
Forum section: electronics / repair

author: Libas
author_rank: Regular Contributor
timestamp: October 17, 2023, 08:55:16 pm
content: Hi there,could somebody help me with diagnostic of this faulty LCD monitor?After power plugged in screen turns on for approx 1 second, then turns off....after few seconds turns on again for 1 second and turns off again forever.Any advices what could cause such a symptomps?I will also very apreciate any study materials how to diagnose LCD monitors in general.

author: fzabkar
author_rank: Super Contributor
timestamp: October 17, 2023, 08:59:13 pm
content: It sounds like a backlight problem.Service manual:https://elektrotanya.com/lg_w2246s.pdf/download.html

author: RayRay
author_rank: Frequent Contributor
timestamp: October 17, 2023, 09:04:34 pm
content: There are different possibilties, such as a shorted power button, bad power board or t-con board.How to proceed really depends on your level of knowledge & equipment. Of course most faults are fixable with the right knowhow, but if you don't wanna go that route, each board has a part number, which you can look up to find a replacement.

author: Libas
author_rank: Regular Contributor
timestamp: October 17, 2023, 09:09:02 pm
content: Backlight and also picture looks good. Of course Im interested in troubleshoot and board repair...thats why Im here...to learn something newI have equipment available...just dont have enough experience with LCD monitors yet.

author: RayRay
author_rank: Frequent Contributor
timestamp: October 17, 2023, 09:13:15 pm
content: Well, I'd suggest you start by measuring the voltages from the power board (where the connectors go to).You could also do a 50/50 with the flat cables going from the t-con board to the upper (left/right) lcd controller boards (and by that, I mean disconnect one of em, and see it anything changes, try each standalone without the other one connected)

author: Libas
author_rank: Regular Contributor
timestamp: October 17, 2023, 09:14:23 pm
content: It looks to me like power board and also t-con board works "fine"....there is just some fault which shuts if off nearly immediately

author: Libas
author_rank: Regular Contributor
timestamp: October 17, 2023, 09:18:59 pm
content: all electrolytic caps look OK...no bulging visible

author: RayRay
author_rank: Frequent Contributor
timestamp: October 17, 2023, 09:20:14 pm
content: Quote from: Libas on October 17, 2023, 09:14:23 pmI see a huge problem here! You're making quite a bit of presumptions and showing major lack of interest in actually figuring out the problem. So given this, your only repair options are to:1. Verify that the backlight is good by using an lcd backlight tester (personally, I think it's unlikely to be the case, but those testers are quite affordable)2. Try sourcing replacement power/t-con boards by their part number (can be either on a sticker or printed directly on em)If you're not willing to do these things, then just forget about it.I'm being practical.

author: p.larner
author_rank: Frequent Contributor
timestamp: October 18, 2023, 03:44:21 am
content: have you shone a torch as the screen to see if its not just a backlight issue?.

author: Libas
author_rank: Regular Contributor
timestamp: October 18, 2023, 08:45:23 am
content: Quote from: p.larner on October 18, 2023, 03:44:21 amYes...very good comment! I totally forgot such a basic check.Picture is OK...just backlight switches off.Thank you!

author: RayRay
author_rank: Frequent Contributor
timestamp: October 18, 2023, 09:44:13 am
content: Quote from: Libas on October 18, 2023, 08:45:23 amKeep in mind that this doesn't necessarily mean that there's a backlight issue (you'd have to use a backlight tester to know for sure though). It could still be an issue with the power board or t-con

author: Libas
author_rank: Regular Contributor
timestamp: October 18, 2023, 07:03:54 pm
content: problem solved...one CCFL tube had broken connection.As I saw in the internet its common fault. Details for example here in this video:HOW TO FIX HP LCD, monitor turns off after 3 seconds (common repair)