*Possible Purchase Magnovox 32mf338/27 Turns on for a second

[XtraTN]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

I just edited my last post in case you didnt catch it. the pin measured as follows (left to right)

pin1: 6.26V
pin2: 3.3V
pin3: 2.05V

[Mr Bill]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

If the green led flashes a handful of times then turns on this is normal. The emerson LC320EM9 that i have (uses the same power supply) turns on exactly the way you describe.

So you fixed a broken tv by resoldering a cold joint on the inverter transformer. Good Job!

[XtraTN]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

Hmm, I dunno it seems odd to me.

Looking at the block diagram, theres a transistor Q650 that I think is supplying the 5.5V to the LDO. I measured the pins on the transistor and heres what I got.

Pin1: 5.63V
Pin2: 8.80V
Pin3: 6.32V


When the TV is on:

Pin1: 5.80V
Pin2: 35.9V
Pin3: 6.32V

Also, I'm getting a hissing sound on the board with the inverters. Sort of sounds like a gas leak and it happens as soon as the backlights go on.

[Mr Bill]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

Hmm, I dunno it seems odd to me.

Looking at the block diagram, theres a transistor Q650 that I think is supplying the 5.5V to the LDO. I measured the pins on the transistor and heres what I got.

Pin1: 5.63V
Pin2: 8.80V
Pin3: 6.32V

On my tv I'm getting
Pin1: 5.54v
Pin2: 8.45v
Pin3: 6.25v

When the TV is on:

Pin1: 5.80V
Pin2: 35.9V
Pin3: 6.32V

Im getting:
Pin1: 5.97v
Pin2: 36.3v
Pin3: 6.3v

Also, I'm getting a hissing sound on the board with the inverters. Sort of sounds like a gas leak and it happens as soon as the backlights go on.

When i first turn on my emerson it has a loud buzz/hiss in the inverter area too but it goes away after about 20 seconds or so. Maybe run the tv with the back off and see how it does in a real world application.

[XtraTN]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

Hmm i guess its normal then. The only question now is how that burnt mark got there but oh well guess we'll never know . Got a 32" lcd tv for 50$!

I spent over 5 hours disassembling and cleaning every single piece of the TV right down to the backlights. The thing was infested with literally hundreds of dead cockroaches... The most unsanitary thing I've ever seen =/. Eh at least I was able to get an easy fix of of it.

[Mr Bill]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

HaHa
I wonder if one of those cockroaches caused the zap on the board. Atleast it was a an easy fix that didn't cost anything but your labor.

[XtraTN]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

I learn something new with every TV I work on. I'm not opening anymore TV's in my room unless I know its clean. :p Anyway thanks for all the help!

[XtraTN]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

Ugh so theres a new problem....

Theres a vertical blue strip going along the right side of the TV...
Might be a bad panel then =/ but maybe not

It seem to be random as I switch off and on the TV. Somethings it would disappear while I leave the TV on for 5 minutes, and sometimes not.

I unplugged one of the CCFL to simulate the problem I had in the beginning where it would turn on for a second and go off. And everytime I did that, the blue strip would not appear when the TV when on and back off.

So I took off that board and started to reflow and resolder all the joints near the CCFL connectors. But now the blue strip is stuck there and won't even go away now no matter how much I turn on or off the TV or leave it on.

For now I'm going to disassemble the panel to the tabs connecting to the LCD and see if pressing on them causes the blue strip to react.

But any thoughts on this?

[mswillia1]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

I have a Emerson LC320EM9B with Inverted ba8af0f01032. My set doesn't turn on, looks like the board has gotten hot. Do you have the manual for this set?

[Eel_dahc]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

I have this TV as well. $20 pawn shop as is. Sometimes it turns on fine. Sometimes I have to go through the process of pressing power, the light blinks then back to standby, 2 or 3 times before it finally comes on. With the back off and when it tries to turn on but fails, the middle inverter transformers make a buzzing sound. When it works it stays on, no problems. Just sorta turns on when it wants to.

[dskall]

Re: *Possible Purchase Magnovox 32mf338/27 Turns on for a second

Probably bad ccfl