Magnavox 40mf401b/f7

[ryan74]

i have a magnavox 40MF401B/F7 that when you turn it on the stby light in front blinks 18 times for about 5 sec and then goes out. when the light goes out the screen lights dim about 50%. no picture, no sound, no input display(time/channel).

voltage from psu seemed ok but some tp werent labeled or couldnt read so i skipped them. there is a slight hum coming from the long narrow board left of psu.

I think this is common but i couldnt find a thread. I would apreciate help.

another quik question.. is there a good info source for beginner lcd tv repair? a guide to repair with symptoms/solutions. anyone heard of "Mike's tv repair histories"? I found it here www.tvrepairinfo.com after watching youtube videos.

[ryan74]

Re: Magnavox 40mf401b/f7

pics of the 2 connectors on power supply. inverter and main board. i retested them.

inverter con:
pwm-sel = .772v
bl-adg = .76v
bl-5w = 2.95v
error = 3.2mv
24v = 23.90v

main board:
tuner35v = 37.68v
lcd12v = 12.17v
lcd12v = 12.17v
G
G
p-on+3.3v = 3.38v
G
+6.5v for 1v = 7.71v / 190mv
G
p-on3.5v for reg = 3.68v
G
p-on+5v = 5.27v
G
24v for amp = 27.46v

[ryan74]

Re: Magnavox 40mf401b/f7 blinking light

there is a slight hum coming from the long narrow board left of psu.

i meant the inverter board.

[ryan74]

Re: Magnavox 40mf401b/f7

any help? please

[budm]

Re: Magnavox 40mf401b/f7

The inverter is getting all the correct voltages from the power supply and from the main board but it is sending ot an ERROR signal, if the Inverter board is fucntioning, the ERROR pin will be >3VDC, rught now it is LOW= ERROR.
I need to see GOOD CLEAR FOCUSED pictures of the area around the connectors of the inverter board and the whole board that the cables from the power supply board are plugged in. I think you have a blown fuse for the PWM IC. See fuse F5 in the picture.
I also need the LCD panel model number, there should be a sticker on the LCD panel showing the model number.

[ryan74]

Re: Magnavox 40mf401b/f7

panel number:
Samsung
1124 lta400hm09
p7ah 7hbf30136g f02

inverter:
samsung
ss140008a01 rev 0.2
03241awb32156h0

main board:
a17po-mjc
e7215900

power supply:
a17po-mpw
e7215910

i see a 10a 125v ceramic type fuse but nothing else.
if your sure its just the inverter board i can just replace it. shopjimmy has it

[budm]

Re: Magnavox 40mf401b/f7

I will have to look up the panel number to see what you should have at the ERROR pin.

[ryan74]

Re: Magnavox 40mf401b/f7

i retested error pin grounding to chassis and got 4.8v. last time i grounded on the board

[budm]

Re: Magnavox 40mf401b/f7

I cannot find the datasheet form the site that does not need you to join to get access to download the spec, Panelook.com require registration to download the spec sheet.
By the way, is the fuse on the inverter OK? Do you get 24VDC on both ends of the fuse?

[ryan74]

Re: Magnavox 40mf401b/f7

23.88v on both sides of fuse

[budm]

Re: Magnavox 40mf401b/f7

I am not 100% sure yet if the inverter is bad since I cannot really verify that the Error signal is correct or not. If the Error signal is correct then the inverter board is receiving all the correct signal and also sending out the correct signal, then the TV should not show an error code lights. I will have to look for the service manual to see what the error codes (18 blinks) mean.

[ryan74]

Re: Magnavox 40mf401b/f7

i saw codes for a similar model. code 18 was channel decoder i2c-com error with mt5112(reserved for bds modules), but that didnt seem right to me but what do i know.. thats why im here.

[ryan74]

Re: Magnavox 40mf401b/f7

thanks for the help. I guess I may have to take a chance and buy inverter board for $40. I hope that fixes the problem. If your 80% sure I will take the chance. This model is from 2011 so I guess there isn't much info out there yet. I'm afraid of wasting $$ if its something else.
Anyone else have any ideas.

[ryan74]

Re: Magnavox 40mf401b/f7

I'm rushed to fix this for a friend by next weekend. Sorry if I seem impatient but do you think its worth the risk to buy the inverter board or is there something else I can check or should I shut up and wait for more help? Lol
Does it pay to contact magnavox support for service manual?
What's a good resource for thenewest models?

[budm]

Re: Magnavox 40mf401b/f7

I cannot be sure until I find out what the darn blinking mean. Do you get the same blinking code if you disconnect the power cable to the inverter board? You may have more then one problem also.

[ryan74]

Re: Magnavox 40mf401b/f7

Well I talked to my friend and got the warrant/service number from his owner manual. I called and found this tv is still under warranty so they will send me packaging to ship it for repair. He just has to wait for a 3 week turnaround they said. Sorry I wasted your time but maybe this will help someone.

I also found out my friend tried calling the same number a while ago and they said he had to pay shipping and parts... weird I get warranty

[ryan74]

Re: Magnavox 40mf401b/f7

I unpluged the inverter board, plugged in power. Solid front led
Turned on power, heard 1 click, red led flashed 18 times and went out
Pressed power and it solid red
PressedPower again, click, 18 blinks, led goes out
It repeats every time

Unplugge!d power
Reconnected inv
Reconnect power, 18 blinks
Backlights comes on led goes off
Pressed power, backlights go off, shutdown
Front led comes on

[ryan74]

Re: Magnavox 40mf401b/f7

magnavox support first said it was covered and they would send out shipping packaging.
i called today and now they said it is not covered by warranty and wont fix it.
so now im back to figuring this out.
when i power it up the front led blinks fast 18 times but i dont think its a code.
then backlight comes on but no pic, no sound, no menu, nothing but a white screen.
i rechecked voltages. last time i must have error tested on bl_sw. there next to each other.

pb con to inv:
pwr_sel = .77v
bl_adj = .77v
bl_sw = 2.97v
error = 0
g
g
g
g
g
24v = 24v
24v = 24v
24v = 24v
24v = 24v

pb con to main board:
tuner35v = 37.68v
lcd+12v = 12.16v
lcd+12v = 12.16v
g
g
p_on+3.3v = 3.38v
g
+6.5vfor1v = 7.68v
g
p_on3.5vforreg = 3.5v
g
p_on5v = 5.2v
g
24vforamp = 27v

pb ribbon cable to main board:
g
protect3 = 3.0v
protect1 = 3.1v
bl_sw = 3.28v
bl_adj = .71
pwrreset = 2.8v
p_on_h2 = 3.1v
p_on_h1 = 3.3v
g
g
g
all4.3v = 4.3v
all4.3v = 4.3v

it all looks good to me. what do you think?
from the main board theres 2 ribbon cables that go to hdmi jacks and from there to top of lcd panel. does video signal travel through inverter or is that just for backlights.

[budm]

Re: Magnavox 40mf401b/f7

The inverter does have all the required signals and voltage, it looks like you just have to try the new inverter board, there is no easy way to test the lamps in the panel.

[ryan74]

Re: Magnavox 40mf401b/f7

all i get is backlight. (white screen) see pic.
i will start looking for one online.

the lines in pic i dont see on tv