Magnavox 42MF337B/37 won't power on

[baconboy08]

Hello I bought a Magnavox 42MF337B/37 TV along time ago. Well I recently upgraded that tv with a new one. So I gave it to my mother in law. Well one night my wife got a phone call from her and said that the tv went out. They said that it would not turn back on. I told them I would look at it for them to see what is wrong with it.

I do not have much, if not any, tv repair skills. I can solder and follow directions really well though.

So I have been trying to firgure this out on my own. I have been reading all over the web about the this tv. I know it shares the model numbers with other tvs like, Magnavox 42MF337B/37, Magnavox 42MF437B/37, Philips 42PFL5432D/37, Philips 42MF337B/37, and Philips 42MF437B/37. I have been looking at all peoples problems with those model numbers.

The problem I am having is that the tv will not turn on. The power button led light wont even turn to red. I opened the back and the 4 caps that usually go bad, appeared to be fine. I replaced the 4 caps, just in case they did go bad and were not showing it. I plugged it in and tried to turn it on. It still did the same thing as before, nothing. I got a tester and saw that the diodes were getting 12v-15v of electric to most of them. I checked out the MOSFET at location Q901, Q902, and Q908 seemed to be getting some power, but D927 was not.

So I do not know what to do from here on out. So any help would be great, even it is telling me that I did something wrong and need to redo it.

[retiredcaps]

Re: Magnavox 42MF337B/37 won't power on

Now power LED suggests the problem may be on the main board.

The components circled in red are voltage regulators.

1) List each part number.

2) Put your black probe on a ground screw on the main board and leave it there.

3) For each regulator, number the pins 1, 2, and 3 left to right. The fat tab is "up" or "north".

4) Put your red probe on pins 1, 2, and 3 for each regulator.

5) Report your findings like this.

U101
AS1117-33
pin 1 = 0.0V
pin 2 = 3.3V
pin 3 = 5.0V

[cashkennedy]

Re: Magnavox 42MF337B/37 won't power on

Did you check the voltages exiting the PSU? try "turning it on" then test them again and see if any of the voltages that are usually off (12v, 24v) turned on.

I assume all the parts you mentioned testing are on the main board and not the power supply?

[budm]

Re: Magnavox 42MF337B/37 won't power on

One of these service manuals should match your chassis:
http://elektrotanya.com/?q=showresul...oria=&kat2=all
What is your power supply board number?
What voltages do you get at the top left white connector which goes to the main board?
This power supply has PFC Voltage booster circuits, it does not have standby 5 volt power supply, it has 12v standby power supply instead, the 12Vdc is on pin 3,4 of CN902.
CN902 pin 10 is for turning on and off the PFC Voltage booster circuits and the 24vdc power supply for the backlights inverter boards

[Unreal701]

Re: Magnavox 42MF337B/37 won't power on

I will start by saying I only have a basic knowledge of electronics, I am good with capacitors and resistors but once you guys start talking more in depth is when I start getting lost. I am experiencing the same problem as the original poster. Same model tv and the images of the boards are identical to my own, I have checked the caps and none are obviously swollen. What would my next step be?

[mrgcav]

Re: Magnavox 42MF337B/37 won't power on

Need a service manual for a 42MF337B/37 Magnavox. Need to identify some burnt parts.
Please Post off site or send S/M to MRGCAV@gmail.com
I have limited download capability from sites outside the USA.
thanks

[nomoresonys]

Re: Magnavox 42MF337B/37 won't power on

with meter on dc mode, check expected voltages at the connectors on power supply board, should be a label of expected voltages by the connectors, don't know how everyone does it, I check m with tv powered on, if you don't at least have the 5 volt standby, check your fuse on power supply board, as always be careful working with power supply, HIGH VOLTAGE, on primary side can be deadly.

[mrgcav]

Re: Magnavox 42MF337B/37 won't power on

Still require a service manual. Please help.
All it does is chirp We replaced the main filters already.
Magnavox 42MF337B/37

[mrgcav]

Re: Magnavox 42MF337B/37 won't power on

Finally found the manual. Can not search by model number but rather by chassis number TMP1.0u-la

Phillips TV 15MF227b,15MF237s,19MF337B,19PFL5402d,19PFL5422D,19PFL5622D Chassis TMP1.0u-la.PDF

http://www.electronica-pt.com/esquem...artdown/23907/

[budm]

Re: Magnavox 42MF337B/37 won't power on

Finally found the manual. Can not search by model number but rather by chassis number TMP1.0u-la

Phillips TV 15MF227b,15MF237s,19MF337B,19PFL5402d,19PFL5422D,19PFL5622D Chassis TMP1.0u-la.PDF

http://www.electronica-pt.com/esquem...artdown/23907/

Not for 42", only for 15" and 19''. Philps uses same chassis numbers but you also have to match the model also not just the chassis number.

[mrgcav]

Re: Magnavox 42MF337B/37 won't power on

But it does not cover the 42" version. Just my luck.
Their are two parts to this manual
Part 1
Phillips TV 15MF227b, 15MF237s, 19MF337B, 19PFL5402d, 19PFL5422D, 19PFL5622D Chassis TMP1.0U-LA Part 1.pdf
Part 2
Phillips TV 26MF337B27. 26MD357B37. 32MF337B27. 32MD357B37. 37MF337B37. 37PFL5332D37. 42MF337B37 TPM1.0U-LA Part 2.pdf
Since it is a PDF it should be one manual.
I obtained Part 2 from
http://www.manual-archives.com/Membe...ads/95033.html
and had to pay a $5.00 membership randsome.
I am beginning to hate this TV.

If you need a copy email me
MRGCAV@gmail.com