Magnavox 50MF231D/37

[jhd2112]

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Hi my name is Joe and I am working on a Magnavox 50MF231D/37 that I got for Free! it had bad power supply because it smoked two capacitors 35V 470uF 105C replaced. I got power to all boards and adjusted all voltage to right settings + or - 2v. I do not have video or sound but all boards light up but the asic main logic board has one led power side light on and on start up one lower has two leds one lights and goes out and the other starts flashing. Is the main logic board fried?:

[jhd2112]

Re: Magnavox 50MF231D/37

got the tv in stand by mode just need to get reflashed by service mode because of problem with startup mode any one know where I can get a reflash program?

should I let the green led flash till it ends or just turn it off and take tv into tech to reflash IT?
Not sure what to do.

TV just go into green led mode flashes 1 long flash and 3second later flashes 4 quick flashes. Not sure can I still get a copy of USB flash drive to acept into it?

Where can I get it?

[ljintexas]

Re: Magnavox 50MF231D/37

I have looked for firmware and it used to be available from Magnavox...But I cannot find it anywhere. Ma have to email Mag support

[ljintexas]

Re: Magnavox 50MF231D/37

Logic board could be toast. I just bought one from TriState Modules for $20. Also could have damaged main board..

[jhd2112]

Re: Magnavox 50MF231D/37

Replaced asic Logic board, is Main board the Y and X sus? Got power but fails at start up. So no red Led flashes, right?

[jhd2112]

Re: Magnavox 50MF231D/37

Sorry, Main Logic Board, right?

[ljintexas]

Re: Magnavox 50MF231D/37

Have you tried the self test for main logic board? Find 4 pin jack on board pins are labeled 1,2,3,4 and they look liek hard drive pins..I used hard drive jumper across 3 and 4. then disconnect lvds cable..hook everything else back up and plug in..shoudl give you colored screens and test patterns if logic board is good.

[jhd2112]

Re: Magnavox 50MF231D/37

Ok I will give it a try Thanks I will let you know what happens

[jhd2112]

Re: Magnavox 50MF231D/37

Got nothing I will get another Board. Thanks for giving me a helping hand.

[jhd2112]

Re: Magnavox 50MF231D/37

put in another Main Logic Board but no life. I Checked power supply got good voltage at all points. I checked voltage at lower power supplied board have power there 5.16 volts but check power at first jumper wire ground good has 5.16 pin 3 but does not have 30V at pin 2. Are these the Y sus buffer boards they go across the bottom of TV?
put in another Main Logic Board but no life. I Checked power supply got good voltage at all points. I checked voltage at lower power supplied board have power there 5.16 volts but check power at first jumper wire ground good has 5.16 pin 3 but does not have 30V at pin 2. Are these the Y sus buffer boards they go across the bottom of TV? The X and Y sus have power. The 5v, 3v,& 1v are all there. What should I check next there are no blown fuses but it powers up but it is missing what start up signal. Any Ideal? If I plug it in starts up all lights are green but have one flashing on Main logic board telling me it needs one more signal to light the screen, all power lights stay green. Any Ideal? Thanks

[tw2005]

Re: Magnavox 50MF231D/37

The boards in this Tv , are they LG or Samsung?

[ljintexas]

Re: Magnavox 50MF231D/37

Mine are all Samsung...

[tw2005]

Re: Magnavox 50MF231D/37

I think to help this along some photos of the boards and some actual voltages with their correct identifiers would be handy.

Statements like
I Checked power supply got good voltage at all points.

Followed by

I checked voltage at lower power supplied board have power there 5.16 volts but check power at first jumper wire ground good has 5.16 pin 3 but does not have 30V at pin 2

I'm having trouble understanding especially the 30V. I don't know of a 30v source

I suspect at this point it's the voltage to the E,F,G buffers Va that's being checked which should be around 60V

I'd find the following identifiers and report what voltages are there.

these are just a guide

1 VS 207 V
2 VA 63 V
3 VE 94 V
4 VSCAN -190 V
5 VG 15 V
6 D5VL 5.2 V

With those lower buffers (bottom of panel) don't run the TV with the full width heatsinking strip removed or it will be the end of the panel.

[jhd2112]

Re: Magnavox 50MF231D/37

Ok here are the voltages from power supply.
VS 202.4V 8V6 8.7VOn both Y and X boards
Y board
Vest 190.4V SND P 17.3V
Both X & Y
Va 65.5V 5V2 5.2V

Ve 110.5V 12V 12.4V

Vsc -185.6 5v sw 5.3V

Vset 190.4V S_ND Pos 5.3V
Not sure how to check Vsc_h but using other location on board got?
Vsc_h -65.5V snd_N 17.3V
When checking Voltage on buffer boards
Have correct voltage at I believe E buffer board
Board to board jumper E to F
Listed on board
Pin 1 Ground
Pin 2 is suppose to be 30v got 5.3v
Pin 3 is 5.3 volts got 5.3v
Pin 4 NC no volts
Pin 5 Va got 65.5V
Not sure how to test E, F, G boards but lacking power on pin two might be a problem with start up mode? I have no Ideal? I also will post some picture for help. Thank you for your responces

[tw2005]

Re: Magnavox 50MF231D/37

Ok here are the voltages from power supply.
VS 202.4V 8V6 8.7VOn both Y and X boards
Y board
Vest 190.4V SND P 17.3V
Both X & Y
Va 65.5V 5V2 5.2V

Ve 110.5V 12V 12.4V

Vsc -185.6 5v sw 5.3V

Vset 190.4V S_ND Pos 5.3V
Not sure how to check Vsc_h but using other location on board got?
Vsc_h -65.5V snd_N 17.3V
When checking Voltage on buffer boards
Have correct voltage at I believe E buffer board
Board to board jumper E to F
Listed on board
Pin 1 Ground
Pin 2 is suppose to be 30v got 5.3v
Pin 3 is 5.3 volts got 5.3v
Pin 4 NC no volts
Pin 5 Va got 65.5V
Not sure how to test E, F, G boards but lacking power on pin two might be a problem with start up mode? I have no Ideal? I also will post some picture for help. Thank you for your responces

I think pics would be handy. I'm not exactly up with these but the 30V is confusing. At least it appears the voltages are normal. I was hoping Va was down and that was it but appears not

[jhd2112]

Re: Magnavox 50MF231D/37

sorry Forgot VS
vs both boards
VS 202.4v 8V6 8.73V

[tw2005]

Re: Magnavox 50MF231D/37

Ok here are the voltages from power supply.
VS 202.4V 8V6 8.7VOn both Y and X boards
Y board
Vest 190.4V SND P 17.3V
Both X & Y
Va 65.5V 5V2 5.2V

Ve 110.5V 12V 12.4V

Vsc -185.6 5v sw 5.3V

Vset 190.4V S_ND Pos 5.3V
Not sure how to check Vsc_h but using other location on board got?
Vsc_h -65.5V snd_N 17.3V
When checking Voltage on buffer boards
Have correct voltage at I believe E buffer board
Board to board jumper E to F
Listed on board
Pin 1 Ground
Pin 2 is suppose to be 30v got 5.3v
Pin 3 is 5.3 volts got 5.3v
Pin 4 NC no volts
Pin 5 Va got 65.5V
Not sure how to test E, F, G boards but lacking power on pin two might be a problem with start up mode? I have no Ideal? I also will post some picture for help. Thank you for your responces

I think you may be chasing a ghost. From what i see at the PSU end there are only 3 of those pins connected, 1,3,5. Viewed from the top at CN8005, left to right, first pin Va , 2nd NC, 3rd 5V, 4th NC, 5th gnd

[jhd2112]

Re: Magnavox 50MF231D/37

Pins are listed on board E to F jumper with volts listed on board. that is on E board pin 2 has low volts i believe.

[tw2005]

Re: Magnavox 50MF231D/37

ok, i think i've just clicked on where you refer on the connection E buffer - F buffer pin2 35V. Not sure , may have one of these I can look at but notsure it's relevant. can you trace that pad because just because it's labelled 35V may not mean that is so. Only 5v and 60v going into this board so either it's developed on this board from the Va or it's simply wrong label.

[jhd2112]

Re: Magnavox 50MF231D/37

“I think you may be chasing a ghost. From what I see at the PSU end there are only 3 of those pins connected, 1,3,5. Viewed from the top at CN8005, left to right, first pin Va , 2nd NC, 3rd 5V, 4th NC, 5th gnd”

Yes I barrowed the Ground from power supply to test jumper wires because pins are pretty tight, (I wanted to avoid a short) but uses same supply for voltage test. All power leads tested well at power supply. I know PSU is good but TV is stuck in Stand By Mode