magnavox 32mf231d/37 no power backlights flicker

[shelby5041]

hi

i know this was a thread before but there was no fix

i have this tv it does not power on...no power light...no picture..no sound....whats really odd is that when plugged in the backlight immedialtey turns on and flickers on and off and i hear a buzzing sound coming from power supply......i have replaced the 1200uf and 2200 uf caps....no change

i do get 16v and 24v going to scaler board....when i check voltages going to inverter board the voltage fluctuates as the bl flicker ....low to high voltage....

as the backlight flickers there is a blue led light on the inverter board that flickers also.....

if i unplug the power cable to the inverter board i get no voltages coming from power supply.to the inverter cable...i only get voltages going to inverter when i have the cable actually plugged in to the inverter board.........

im looking for any help.....i got help frokm this forum last month and ended up fixing the tv so i hope i can get some help again....i learn from you guys and i appreciate it

i also checked 5 diodes located near the large transformer on the power supply using ohms and on 4 of them i get no reading one way and a reading the other way.........but on one i get a low reading both ways.....suspect?

thank you

[football0062]

Re: magnavox 32mf231d/37 no power backlights flicker

do you have voltage at fuse 1U01 on the scaler board? next to the big coils for your audio circuit? if not flip the board over and check IC 7003 in the audio circuit. its an 8 pic surface mount with a center pad underneath.

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

ill check for voltage and get back in a few min

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

no voltage at all....0v

the fuse is good

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

what am i checking on the ic7003?

[football0062]

Re: magnavox 32mf231d/37 no power backlights flicker

ya fuse should be fine. unplug and check resistance from fuse to ground

[football0062]

Re: magnavox 32mf231d/37 no power backlights flicker

checking for shorts or physical defect(blown open)

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

not sure how to check for shorts on the ic

[football0062]

Re: magnavox 32mf231d/37 no power backlights flicker

whats your resistance from that fuse to ground? use tuner housing as a good ground

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

does it matter which end of fuse?? ill do both ends and give you readings

[football0062]

Re: magnavox 32mf231d/37 no power backlights flicker

not if the fuse is good it wont matter lol

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

if i touch black to top fuse and red to tuner ground i get 76 ohms

if i touch black to bottom fuse and red to tuner i get .3 ohms

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

oh let me use red on fuse one sec

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

sorry did it wrong first time..i get 20 ohms both ways....

[football0062]

Re: magnavox 32mf231d/37 no power backlights flicker

same thing that happen to mine. i have a new board on its way i will let u know how it works out, but my IC 7003 on the bottom was cooooked. black carbon all over. fuse is fine and resistance is around same as what your getting on your board. i dont have a schematic but i know most boards will shut the unit down if its not receiving the correct voltage to the audio circuit, which would be where that fuse is. im guessing your screen lights up for 2 sec max then shut back off?

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

do you suspect its a bad power supply or bad main board?

any ideas?

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

backlight flickers on and off....tv does not actually power on at all..i get no led power light at all....no picture ......just backlight flickering on and off

i got a great price on a power supply board and main board tonite

i got the power suppply for 22.95 shipped
and i got the main board for only 34.00 shipped

two diff ebayers.....i guess i cant go wrong....the one i dont need i just can resell and maybe even make a little profit since i got incredible price

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

ill let you know also on my results when i install the boards i ordered in a few days

[football0062]

Re: magnavox 32mf231d/37 no power backlights flicker

ive replaced with 4 different power supplies, still flickers on ever single one of them. finally got a 4am 24v LED driver for $12 and ran the inveters off that and no flicker but still shuts off. thats when i noticed the main board issue. will let u know when i receive the main board. also ive replaced the inverters on this set too. still flickers. this main board is the only thing left really. ive actually torn it down to the bulbs and they are fine as well.

[shelby5041]

Re: magnavox 32mf231d/37 no power backlights flicker

the main board on this tv is a very common issue.....so im thinking the same but for such a cheap price i got both...that way i can be for sure....i got the tv for 10.00 so it would be worth fixing i think....even though its getting more and more not worth fixing any lcd tv anymore since a brand new 32 inch is 149.00 at walmart