Repair Touchscreen Monitor 5005L - Page 1
Forum section: electronics / repair

author: SimonPbr
author_rank: Newbie
timestamp: July 27, 2015, 12:21:23 pm
content: Hi everyone,this is my first post on the forums. Been following Dave's blog for a while now and it certainly got me into trying repairing things again instead of buying new.Today I got this 15 inch touchscreen monitor by some chinese company without a name (at least I couldn't find one). The modelnumber is: 5005L and it was manufactured in 2010.When I plug it in and press the power button it turns on, then a weird crickling noise comes from the part which I'll post a picture of (and that I'm pretty sure causes the problem) but can't identify. It will probably easy to you guys but I have absolutely no EE background and am a pure hobby youngster.So my questions are: What is this part and obviously is it replaceable (and is it worth doing so)?I got some soldering skills. I replaced some of the caps already as that was my first suspection for the cause of the failure.Thanks ahead and I'm looking forward to learning something from you guys. (Of course I'm happy to provide more info if needed and apologize if I'm missing something crucial)Best regards,Simon

author: SimonPbr
author_rank: Newbie
timestamp: July 27, 2015, 12:50:46 pm
content: Ok, just lifted the yellow heatresistant tape and revealed the part number. I'm quite sure now that it is an inverter (even though I still don't really know what it is good for). I thought parts like that would never break but it seems like some kind of black substance is coming out on the one side (sorry, can't see that too well on the picture).The part number is ktc-401-0319-22114G. Does not look too promising in terms of fixing, or is it possible to find out the specs of that part without a datasheet?

author: amyk
author_rank: Super Contributor
timestamp: July 27, 2015, 01:53:14 pm
content: It could be the transformer or some other part on the primary that's failed. Be careful as they can put out very high voltages.CCFLs and their inverters are pretty generic. If you figure out the input voltage and the controller pinout you can replace it with any other one for the same number and length of lamps.

author: SimonPbr
author_rank: Newbie
timestamp: July 27, 2015, 02:23:05 pm
content: Thank you amyk for the reply!I desoldered the transformer and checked it for any obvious breaks but couldn't find any besides the before mentioned black glue (or some kind of insulation).I still assume that this is the faulty part however as the strange noise upon powering the main board is gone. I checked and the pcb that the transformer is on receives 5V from the main pcb. There are two power cables going away from the transformers pcb. Can I assume it supplies two lamps or should I try to get in and really check the lamps out?I'm not quite sure how to figure out the controller pinout though.

author: BennVenn
author_rank: Regular Contributor
timestamp: July 27, 2015, 10:18:57 pm
content: Its a generic CCFL driver, you can pick them up on ebay for a few dollars. The brightness control voltage may or may not be in phase with what is currently used, that is 0-5v dim-bright etc...You can fit the generic driver and set it up at a set brightness or build a circuit to invert the signal to what is expected. Or it may just work out of the box!