Aoc n20wb

[ronhayes]

Re: Aoc n20wb

Thank you Vince
I have tried to re-measure the transformer while it is out and i get nothing like that ?
In the 2k range i get primary .001 and secondary i get .471 then in the 20k range i get primary 0.00 and secondary i get 0.46
can you look at this picture am i right with the primary and secondary ?

[vinceroger69]

Re: Aoc n20wb

thats certainly how i would measure them, those readings the ebay seller sent me certainly did sound odd im hoping budm will have a idea im still learning so unsure hence usually wait for budm or a more experienced member to confirm

[ronhayes]

Re: Aoc n20wb

Yes my measurements are no where near what they say .
Hopefully budm can confirm it ?
Let me know what you want for a ccfl tube if you have a spare one you can let me have.
Thank you Vince .

[budm]

Re: Aoc n20wb

At this point I am not convinced that we do not have bad lamp/s because the lamp tester does not have protection circuit, it still light up one lamp without shutting when not all 4 lamps are connected to the tester.
If it is my board I would use the two test lamps to find out if the board is good or not, that is how I always verify the board when I have 3-second to black problem.
I really do not know for sure if the secondary winding should be around 500 Ohms or 600 Ohms or not, the primary side will have very very low Ohms.

[vinceroger69]

Re: Aoc n20wb

ron ive posted you two 19in ccfl and two 15in ccfl you should get them tomorrow hope these help with your fault finding on this project and future ones you may even be able too use one of these if you find that ones faulty in this monitor

[ronhayes]

Re: Aoc n20wb

Thank you Vince
After what budm said i thought i would wait until i had a ccfl so i could carry out this test.
Just let me know if i owe you anything for them?
Really do appreciate you help.

[vinceroger69]

Re: Aoc n20wb

no you owe me nothing, glad i can help you i always keep ccfls tubes out of laptop/monitors and tvs as never know when you may need one for testing/repair,
and yes i do understand what budms saying now regarding the protection circuit of your tester and thanks again budm for your input into this fault/thread

[ronhayes]

Re: Aoc n20wb

I received the ccfl tubes today from Vince (thank you Vince) i have been to hospital for more tests so could only test the tubes now. there are two tubes running along the top of the screen and two running along the bottom i un-plugged one at a time starting at the bottom of the screen and substituted each one with the ones i received from Vince !
It turned out that one of the tubes on the top two was faulty as when i replaced it the back lights stayed on .
So i now need to strip the screen down to remove the tubes so i can measure them but it does look like they are 18" . A big thank to (budm and vinceroger69) with out there help i would not have sorted this issue.
If any one knows of the best place for me to get replacement ccfl tubes from it would be very helpful.

[budm]

Re: Aoc n20wb

Glad to hear and now we also have to pay caution to how the CCFL tester function and its limitation, the company that makes it probably does not provide full details info on how it functions as far as the protection is concerned.

[vinceroger69]

Re: Aoc n20wb

Ron im not sure what size tubes i sent you so dont know if there too long or too short maybe you could use one of the shorter ccfl i sent you and mount it central in the metal bracket? one you have the old tube removed measure the exact tube size i will see what else i have spare, and hope your hospital tests etc come back ok.Ron also check the wiring on both ends of faulty tube as have seen these at fault before and a quick re solder sorted it and be careful with these tubes they break really easily on removal/replacement and aliexpress are the cheapest for the tubes ive found just measure length and how thick the ccfl is.

[vinceroger69]

Re: Aoc n20wb

Glad to hear and now we also have to pay caution to how the CCFL tester function and its limitation, the company that makes it probably does not provide full details info on how it functions as far as the protection is concerned.

yes like you say its was good too find out this testers limitations as it was hard too tell if the inverter was at fault or not but we have rons readings of the winding ohms that are good for future reference.

[budm]

Re: Aoc n20wb

Test lamps always save me time to narrow down the problem, definitely one of the required test pieces.
I have lots of them!
https://www.badcaps.net/forum/showth...274#post807274

[vinceroger69]

Re: Aoc n20wb

Test lamps always save me time to narrow down the problem, definitely one of the required test pieces.
I have lots of them!
https://www.badcaps.net/forum/showth...274#post807274

Thats a lot of spare lamps budm, certainly be able too save a fair few more monitors etc from the landfill for a few more years and saves buying them as there not cheap new so makes a lot of monitor uneconomical too fix when you have to purchase new parts.

[ronhayes]

Re: Aoc n20wb

Vince here are the ccfl tube carrier removed they are 2.4mm tubes and 18" long as seen in the photo . not sure how to remove the end rubber caps without braking the tubes ?
The ones you sent me are 14" and 19" but they look the same diameter 2.4mm.
Don't worry if you don't have any.
They told me that i will have to have more P.E.T.scans after my next lot of chemotherapy as they have seen another mass further down in my stomach and they need to put a camera down to check it out.
I have only had one session of chemotherapy so far which was carried out over two days.
But so far i am feeling fine but they tell me it will get worse with more chemotherapy.

[ronhayes]

Re: Aoc n20wb

Sorry forgot to add these photos.

[vinceroger69]

Re: Aoc n20wb

i will have a look when im back at home and see what size i have in my spares is the white end cap rubber im sure i just pull them of the ends i usually cut and double heat shrink the ccfl wires as save trying to solder on too the tube pins as solder dosnt seem to like to stick too them.

[vinceroger69]

Re: Aoc n20wb

ron the nearest i have measuring like you are is just under 16.5 i have a pair of these i think came out of a monitor.

[ronhayes]

Re: Aoc n20wb

Hi Vince
I was working on the tv today and trying to determine which tube was faulty when i had removed them, So i connected one with one of the ones you sent me it powered up and stayed on so i tried the other one to confirm it was the faulty one but that one powered up as well so i then connected them both up and the backlights powered on and stayed on.
I tried gently tapping and moving the tubes to make sure they stayed on and did not flicker on/off ,they stayed on. So i put all the monitor back together and connected it to my pc for testing it has now been on most of the day with no issues so hopefully it is a fix. (it must have been a doggy connector as you had said it could be.
A very big thank you to you and budm for all your help with this one with out your help i would never had solved it myself.
I have been put on the sick for six months so hopefully i can get more practise on these lcd's and gain much more needed experience.

A big thank you to you and budm for your patience with me thank you.

[vinceroger69]

Re: Aoc n20wb

Thats good news i have repaired a couple where the wiring on the end of the ccfl has broke (under that white rubber/plastic bit on the end of the tubes) some times you do see a burn mark,but like you say its working for now and may continue too for a lot longer and yes ron keeping busy the next few months will/may do you good and with this electronics hobby were always learning.