MAGNAVOX no picture powers LED 47MF437B/37

[scatman0000]

Re: MAGNAVOX no picture powers LED 47MF437B/37

Using the 200k Ohm selection on meter this is what I got.

Q901 - Pins 1 & 2 = Just infinite reading
Q901 - Pins 1 & 3 = Just infinite reading
Q901 - Pins 2 & 3 = Numbers rise then goes infinite

Could The "Q901" reading be that way because I do not have the ZD902 & ZD904 back in yet?

Q902 - Pins 1 & 2 + 2 &3 = Numbers rise then go infinite
Q902 - Pins 1 & 3 = 27.3

[budm]

Re: MAGNAVOX no picture powers LED 47MF437B/37

oops.

[scatman0000]

Re: MAGNAVOX no picture powers LED 47MF437B/37

Oops! ?

Sounds Bad

[budm]

Re: MAGNAVOX no picture powers LED 47MF437B/37

I see why the D912 is reading shorts in both direction, it is in parallel with the Source resistors R880, R981 (on the bottom side, I cannot really read the designators), and R949 on the component side of the board of Q901. So you D912 is OK after all.
If the two Zener Diodes (ZD902, ZD904) has low leakage resistance, the switching circuits will not work.

[scatman0000]

Re: MAGNAVOX no picture powers LED 47MF437B/37

so hopefully after installing the new ZD diodes (ZD902, ZD904) it should work correct?

[budm]

Re: MAGNAVOX no picture powers LED 47MF437B/37

That is what we are hoping for.

[scatman0000]

Re: MAGNAVOX no picture powers LED 47MF437B/37

I would like to thank you guys!!

I will wait until I get my new diodes installed and then go from there.

Thank you again!

[scatman0000]

Re: MAGNAVOX no picture powers LED 47MF437B/37

Success !!! Received new Diodes soldered them in and wham TV is working now.

One problem though, There is a Faint Black Line In the middle of the screen.

It is almost gone in bright scenes, Most visible during dark scenes.

Any input on that?

Thank you for helping with the power supply everyone!!!!

[Mr Bill]

Re: MAGNAVOX no picture powers LED 47MF437B/37

Success !!! Received new Diodes soldered them in and wham TV is working now.

One problem though, There is a Faint Black Line In the middle of the screen.

It is almost gone in bright scenes, Most visible during dark scenes.

Any input on that?

Thank you for helping with the power supply everyone!!!!

My cousins 37" philips has a faint circle in the screen. ABout the size of a golf ball. You can't really see it unless your looking for it. We are thinking that the screen may be delaminating itself due to the heat from the bulbs and from the power supply but thats only a guess.

[retiredcaps]

Re: MAGNAVOX no picture powers LED 47MF437B/37

One problem though, There is a Faint Black Line In the middle of the screen.

It is almost gone in bright scenes, Most visible during dark scenes.

Clean and reseat every connector whether you touched it or not while fixing the power supply.

[scatman0000]

Re: MAGNAVOX no picture powers LED 47MF437B/37

I will open it up tonight and try the connectors.

Thanx

[van18]

Re: MAGNAVOX no picture powers LED 47MF437B/37

I finally found a new Magnavox Philips power supply 715T2454-2 996500045188. I powered up my TV today and BINGO. This is on ebay...not a repair but a replacment. Thanks to everyone for there help!!! here is the link if anyone is interested!!!

http://cgi.ebay.com/ws/eBayISAPI.dll...m=120899479032

[scatman0000]

Re: MAGNAVOX no picture powers LED 47MF437B/37

Hello, Well I tried reinserting any connectors. No luck on the black line.
Here are some photos of what it looks like.

Not the end of the world if it cant be fixed, Its not bad enough to make you not watch it.

It is almost completely gone in some scenes. It runs from the top to about 3/4 of the way down.

Read somewhere that it might be that two lcd screens were joined together and are now separating at the joint.

Thank you for any insight that you guys might have.

[van18]

Re: MAGNAVOX no picture powers LED 47MF437B/37

Date is 7-3-2012 Just ran across this POWER SUPPLY Guys....if your still looking for the Magnavox Philips power supply 715T2454-2 996500045188..its much more reasonably priced too!! Happy 4th all
http://www.ebay.com/itm/140790251982...84.m1555.l2649

[bjkeds]

Re: MAGNAVOX no picture powers LED 47MF437B/37

Can anyone tell me what ZD diodes (ZD902, ZD904) I need to get for this board??

[Mr Bill]

Re: MAGNAVOX no picture powers LED 47MF437B/37

P6ke120a

[bjkeds]

Re: MAGNAVOX no picture powers LED 47MF437B/37

Thank you kindly. This was a very helpful forum. Attempting to rectify non startup issue with 47MF437B. Hopefully the suggestions on your board will help.

[c.teaman]

Re: MAGNAVOX no picture powers LED 47MF437B/37

Hey everybody, I can see this thread hasn't been active for several months, but I figured I'd check here anyway. I have the same model, 47MF437B, operating with the same problems. No power and chirping. I purchased it from someone who didn't want to try to fix it. It appears someone has already replaced the caps in an attempt to make it run. However, caps C951, C952, and C953 appear to have been replaced with 1500uF/35v caps. It looks like the caps in the pictures earlier on this thread are 2200uF, not 1500uF. I was wondering if someone would be able to verify for me which i should be using?

[c.teaman]

Re: MAGNAVOX no picture powers LED 47MF437B/37

and thanks to all of you who have already posted your help on this thread... reading through the past 5 pages has been extremely helpful. I tested the ZD diodes and they appear to be working properly... about .559 one way, 1 the other.

[c.teaman]

Re: MAGNAVOX no picture powers LED 47MF437B/37

I would really appreciate it if someone could give me some feedback... several of the diodes on my board are reading as bad in the board, but test fine once I remove them. What would cause this?