typical fault in LCD TV

a customer sent me a LCD TV for repair. make and model no. is MEGNAVOX MODEL NO. MLCD32. it goes off while working in unspecific time. some times it keep on operating well even for a week and some times it goes off within a few hours. i have resolidered the power supply, tested the PCB's with heat treatment and also tested for dry joints. But couldn't get the solution for this hidden fault. Can any body help me ?

Muhammad Zulmanun in Islamabad, Pakistan said: this type of problems are with the coponent like relay . with the sparks of current there is cortion in it and some time it works and some time it not work.
if it work pleas reply
if not also reply.

Thank you customer could not wait.

And that why i got out of that biz...use to do well working on consumer products...but this day and age it either gets pitched..returned to the manufacture or will sit on your shelf to dispose of. In Home Customer Service is about the only area....but if you do warranty work for say like Sony...you will get paid more to drive your vehicle than you do for fixing the darn thing and in home service nay take two to three trips sometimes....there goes the profit.

By the way...your problem sounded like a shut down circuit back to the PS....at component level...could be a leaky cap.

Interesting input. You do seem to have a varied background of experience. Being a elect. tech do you have experience with older jukebox repair? I am searching out who can provide that service in this area. I do believe I have met you at the NL. If this is you, do reply. Thanks!

hey I ve got exactly the same model monitor - it's probably the same one as I just bought it off ebay

did you ever get a fix

Suzanne Holguin in Petoskey, Michigan said: Interesting input. You do seem to have a varied background of experience. Being a elect. tech do you have experience with older jukebox repair? I am searching out who can provide that service in this area. I do believe I have met you at the NL. If this is you, do reply. Thanks!

Whats wrong with the jukebox? I have fixed many. let me know the manufactor and what its doing? Get a air compressor, good trouble light, and if smell smoke or the motors 2 or 3 get hot then unplug. later...

It is the bain of us techs that one component, somewhere in the loop, has a thermal problem or perhaps a bad solder joint which increases current to other circuits that make the unit shut down unexpectedly. Further, the unit probably never "fails" while you are on-site. This frustrates the owner and obviously frustrates you because you can't fix a problem that doesn't exist at the time you are there.

Optimally, if you could run this equipment until it fails, you may have a good chance to find a fix. Since this is improbible, I recommend that you concentrate on the components of the power supply in regards to values and good solder joints. This may take time and cost money but you should be able to eliminate the power supply if everything seems normal and the joints are good. Again, the problem is easier to analyze when it is inoperable. If this situation is not a solution, you know that it is probably a weak component in the video (but not necessarily) circuitry. Without a computerized test station to pinpoint any and all abnormal indications, it is trial-by-error. I wish you luck.

25 yrs in electronic repairs...its all the same!
bad solder joint connections from the smt ove line.
after the bad connection heats up from the milli volt drop , then bam.
easy fix is to by some freeze spray,
spray entire circuit bd. see what heats up first
then look with magnification for cold solder, touch up the solder.BEWARE
if solder is resin free!
excessive solder resin will cause cap/ resistors value to changes.USE water soluable solder!

MGehl said: It is the bain of us techs that one component, somewhere in the loop, has a thermal problem or perhaps a bad solder joint which increases current to other circuits that make the unit shut down unexpectedly. Further, the unit probably never "fails" while you are on-site. This frustrates the owner and obviously frustrates you because you can't fix a problem that doesn't exist at the time you are there.

Optimally, if you could run this equipment until it fails, you may have a good chance to find a fix. Since this is improbible, I recommend that you concentrate on the components of the power supply in regards to values and good solder joints. This may take time and cost money but you should be able to eliminate the power supply if everything seems normal and the joints are good. Again, the problem is easier to analyze when it is inoperable. If this situation is not a solution, you know that it is probably a weak component in the video (but not necessarily) circuitry. Without a computerized test station to pinpoint any and all abnormal indications, it is trial-by-error. I wish you luck.

THIS TECH KNOWS WHAT HE IS TALKING ABOUT!

pinballpete@gmail.com in Easley, South Carolina said: Whats wrong with the jukebox? I have fixed many. let me know the manufactor and what its doing? Get a air compressor, good trouble light, and if smell smoke or the motors 2 or 3 get hot then unplug. later...

PBP: could you perform maintenance on a 1969 Rock-o-la 440 that has been sitting for six years? I suspect the grease has hardened and it may need other adjustments.

I am looking for some one that repairs Jukebox's in Sydney can anyone help me out

Peter in Sydney, Australia said: I am looking for some one that repairs Jukebox's in Sydney can anyone help me out

If you can bring them to me in Castle Hill Sydney I will do them for you. I have 37 years experience in electronics. I have my own workshop
Feel free to drop me a line "costas1011@gmail.com"