MAGNAVOX 47mf437b37 No picutre

[Welchs101]

Hi,

I am not an electronics expert but i try to fix "stuff" instead of just throwing it away. I encourage all my friends to try and do the same. Well, a friend tried to fix his tv.........he brought it to me and i said "yep those caps" need replacing...the bulging ones. We did this together and then the tv worked. It worked for about 4 months then quit working ........we did not replace all the caps on the power supply board just a few. So my friend ordered a repair kit online which contained the following caps:
"This Magnavox LCD TV repair kit consists of 11 capacitors, 2200uf, 1500uf, 100uf, 47uf, 10uf, 6.8uf and 2.2uf. It also has two zener diodes to replace the zener diodes ZD902 and ZD904 on the Power Supply Board."

But after replacing all the caps the tv did not work. Prior to replacing the caps when he would try to turn on the tv nothing happened no led lights nothing. after replacing caps from the kit the led lights come on but no picture.

Note: He did not replace the ZD902 or ZD904. I checked these using a multimeter in resistance setting. ZD902: Measured 2.2Mohm in one direction and 1.9Mohm in the other. ZD904: Measured 2.2Mohm in one direction and infinite in the other


If any of you have any ideas on what to look at please let me know.

if you need additional information please let me know.

[wills123]

Re: MAGNAVOX 47mf437b37 No picutre

diodes shouldt have a reading in both directions only one, do you have diode test function on meter? if so use that, might have to desolder the diode that reads both ways and test out of circuit to confirm its faulty

[Welchs101]

Re: MAGNAVOX 47mf437b37 No picutre

will do......

using multimeter diode test function:
ZD902: ~ 0.55V
ZD904: ~ 0.54V

[Welchs101]

Re: MAGNAVOX 47mf437b37 No picutre

oh wait......but i measured those "in circuit" i did not take them out......do i need to take them out? if so just let me know......

[anotherdude]

Re: MAGNAVOX 47mf437b37 No picutre

wouldn't it just be easier to replace them considering you already have the parts?

[Welchs101]

Re: MAGNAVOX 47mf437b37 No picutre

yes, i can replace them but i dont have them at the moment. Did not know he had those as well........but can we not tell something from the measurements i made if the diodes are good or not? just hate to wait a few days to get the parts from him, put them in , and then be right back where we started..........but hey i am the one asking for help so if thats what you want me to do i guess beggers cant be choosy.......

[anotherdude]

Re: MAGNAVOX 47mf437b37 No picutre

yes, i can replace them but i dont have them at the moment. Did not know he had those as well........but can we not tell something from the measurements i made if the diodes are good or not? just hate to wait a few days to get the parts from him, put them in , and then be right back where we started..........but hey i am the one asking for help so if thats what you want me to do i guess beggers cant be choosy.......

but if you have to test them out of circuit, then you'd be able to replace them easily anyway

sorry if I came across as abrupt

[Welchs101]

Re: MAGNAVOX 47mf437b37 No picutre

no problem..........my friend is going to come over one night during the week and we will put the diodes in together then.......will keep you updated on the progress.

thanks.......and no worries!

[hfox]

Re: MAGNAVOX 47mf437b37 No picutre

Sorry to jump in on your discussion, but I have the identical problem and using the same kit of capacitors and diodes, I replaced all of them. The power led will go to green when I turn on the set and stay on, but there is no light from the screen. I measured the 12 volt power section and it is fine. However the 24 volt section shows 2.3 v with no load. I am looking for another source of the problem. Thanks for any assistance.