Magnavox 42MF531D/37

[Fud]

Re: Magnavox 42MF531D/37

This time all were from the negative on the IC to the rest as numbered, this time in the right order and place. Tne meter was set at 200v before it was 300.

1 12.6v
2 neg
3 1.5v
4 .1 v
5 .1v
6 1v
7 .1v
8 165.9v

Sorry for the confusion earlier.

[Fud]

Re: Magnavox 42MF531D/37

There is no delete button on edit i posted the same as above again

[PlainBill]

Re: Magnavox 42MF531D/37

This time all were from the negative on the IC to the rest as numbered, this time in the right order and place. Tne meter was set at 200v before it was 300.

1 12.6v
2 neg
3 1.5v
4 .1 v
5 .1v
6 1v
7 .1v
8 165.9v

Sorry for the confusion earlier.

Those voltages indicate the controller may be working. It is time to investigate the output side of the SMPS. I'll try to look over the pictures later for clues.

PlainBill

[Fud]

Re: Magnavox 42MF531D/37

Not sure what to do now. Take out every capxon cap and replace them or just get a new board for about 180 ( way too much ). But that is better than throwing away a 1300 buck tv i guess. Guess a new board would make more sense than buying a new tv that would probably have the same problems down the line.

BTW the board shows me as logged in at the top but says i haven't logged in to post even after reloading...some bug? Could only post as a quote not a quick reply.

[retiredcaps]

Re: Magnavox 42MF531D/37

But that is better than throwing away a 1300 buck tv i guess.

$1300 for a replacement 42 inch? With the USA thanksgiving coming up, I'll guess that you can get a replacement 42 inch TV with warranty (maybe 2 or 3 years depending on your credit card or if you buy from Costco) for under $400.

[Dgtech]

Re: Magnavox 42MF531D/37

Ebay Item number: 130595808474

Power board replacement. Offer the guy 70, he might take it.

[Fud]

Re: Magnavox 42MF531D/37

Thanks Djtech, I think i'll get the used board from ebay or one of the refurbs there. What i meant earlier is I'm not going to throw away a tv that cost me 1300 bucks a few years back when at most the part is a 100 bucks or if it could be found just some small part that only costs a few bucks.

Besides i don't have the equipment to test capacitors.

[Fud]

Re: Magnavox 42MF531D/37

One last thing before I order a board from Ebay. When put back together the exact same thing, the led where the power doesn't light up at all pressing it or using the remote and no sound whatsoever coming from the unit as in no click or anything as if it's unplugged. Could that just be the switch itself?

[Dgtech]

Re: Magnavox 42MF531D/37

maybe the main fuse blew somehow.

[Fud]

Re: Magnavox 42MF531D/37

Checked the main fuse it's 1 ohm. Silly me thought it would be easy to fix like the last time a couple of years ago.

[Fud]

Re: Magnavox 42MF531D/37

Ok this is a little embarrassing. I got a replacement board from ebay for 70 bucks and the exact same thing no led no power on clicks just like the old one. I can't return the board saying it's broken because it could be fine but another problem. Absolutly no hum click or anything thing. Now i'm either stuck with the thing or take it to a shop which would probably charge 400 or 500 bucks. Just can't help but think it could be something obvious I overlooked. All the symptoms i posted earlier and the voltages etc.

Man i was so happy when i fixed it a couple years ago with just a few bucks in parts but not so much now .

[Fud]

Re: Magnavox 42MF531D/37

I kind of give up on this one, changed the PSU then put in all new caps replaced the capxon ones and nothing. It's like a switch is broken and there is not click or hum or anything when plugged in meanwhile the powerboard does have power to it.

So it's either give it to a tv repair shop and they will fix it finding just one little part and laugh their asses off and charge a ton. Throwing it out not into that really filling up land fills with broken stuff either. It's just that pushing the power on button doesn't do a thing nor through the remote, no click no sound no nothing no led, zilch but there is power going to it. So it makes me think there is a problem with the switch. No it isn't the fuse those were changed on two boards tried out and they were recapped as well.

Would hate to junk it if it's something simple like a reset switch but there are none to be found on the thing anywhere.

[bbjunkie]

Re: Magnavox 42MF531D/37

Don't give up on this one.. the satisfaction of getting it up and running again will be worth the effort.

Dgtech suggested this tv uses the same PSU as the 37MF321D so I have attached for you the schematic for that board.

Looking closely at this will help you see how the circuit is laid out and perhaps help with diagnosis.

Sorry, at this stage I don't know enough about these to give you any hints on where to check next. Hopefully some of the regulars will be along soon to help.

One thing I do find odd though is that the new board is throwing up exactly the same fault as the old one. How confident are you that it is ok? Perhaps this points to a problem on another part of the TV?

Good luck with your repair

Jim

[mr-electrician]

Re: Magnavox 42MF531D/37

Im sorry to post this here but i cant seem to find the "start new disscusion" i have a Magnavox 42MF531D/37 Chassis tpe1.ou la my tv was taking forever to turn on and then would flicker on and off ... and now is dead just a black screen....the led for power is lit up....my question is dose this tv have a bulb that may be bad and if so how do i find it... electronics are not my thing i am an idustrial electrician so i have some basic skills in this field.............the tv is worthless to me now and i have every intention of getting a new one..so with nothing to lose id love to make this one work and give it to a family in need.....any help would be great with pics

[mr-electrician]

Re: Magnavox 42MF531D/37

new update after a complete tear down i plugged the tv back in and the lights all contiune to flicker about 30 seconds in between flickers and the light is only on for about a second....any help is much appericiated

[ben7]

Re: Magnavox 42MF531D/37

I kind of give up on this one, changed the PSU then put in all new caps replaced the capxon ones and nothing. It's like a switch is broken and there is not click or hum or anything when plugged in meanwhile the powerboard does have power to it.

So it's either give it to a tv repair shop and they will fix it finding just one little part and laugh their asses off and charge a ton. Throwing it out not into that really filling up land fills with broken stuff either. It's just that pushing the power on button doesn't do a thing nor through the remote, no click no sound no nothing no led, zilch but there is power going to it. So it makes me think there is a problem with the switch. No it isn't the fuse those were changed on two boards tried out and they were recapped as well.

Would hate to junk it if it's something simple like a reset switch but there are none to be found on the thing anywhere.

You should check the output voltages of the power supply, if all are ok then check the voltages on the regulators on the main processing board. Probably a voltage regulator has gone bad/open-circuit making the TV not respond at all.

-Ben

[Fud]

Re: Magnavox 42MF531D/37

You should check the output voltages of the power supply, if all are ok then check the voltages on the regulators on the main processing board. Probably a voltage regulator has gone bad/open-circuit making the TV not respond at all.

-Ben

Looks like the main board is fried, the chips are almost impossible to replace on them, and used ones are not being sold anywhere at all, So i have two PSU for it which are pretty rare and those can be sold, those were tested and work.

Besides the main board used if found are over 250 so it wasn't worth it anyway.