Magnavox 32md359b/f7 White Screen and with sound only

[tom66]

Re: Magnavox 32md359b/f7 White Screen and with sound only

OK can you test the voltage on it relative to chassis ground.

[YEROC37]

Re: Magnavox 32md359b/f7 White Screen and with sound only

What am I looking for, I'm getting 14.6v second slot then 4th slot 4.6v

[tom66]

Re: Magnavox 32md359b/f7 White Screen and with sound only

I think it's pin 5 you should be testing.

[YEROC37]

Re: Magnavox 32md359b/f7 White Screen and with sound only

Pin 5 no volts,,I'm checking on my schematic to see if it mentions anything

[tom66]

Re: Magnavox 32md359b/f7 White Screen and with sound only

Just be careful you're not transposing it with ground, as they are symmetrical.

[YEROC37]

Re: Magnavox 32md359b/f7 White Screen and with sound only

Ok, so when doing this reading...What would be the best way, I was using the chasis as the ground

[YEROC37]

Re: Magnavox 32md359b/f7 White Screen and with sound only

I'm getting readings from first 5 pins and as I test down on other pins, voltage also seems to be visable

[YEROC37]

Re: Magnavox 32md359b/f7 White Screen and with sound only

on the first pin, I get no voltage and I believe it says INV +16v,

[tom66]

Re: Magnavox 32md359b/f7 White Screen and with sound only

Are you seeing anything on the LCD+16V pins? Hmm, maybe it is a PSU fault after all. I will trace where INV 16V is generated.

[tom66]

Re: Magnavox 32md359b/f7 White Screen and with sound only

It looks like it's generated from the LCD 16V supply which is protected possibly by an overvoltage protector - it's hard to tell from the schematic, but if LCD 16V is missing, then you will not get power for the inverters.

[YEROC37]

Re: Magnavox 32md359b/f7 White Screen and with sound only

Do you have schematic? I can send you what I have

[tom66]

Re: Magnavox 32md359b/f7 White Screen and with sound only

Yes. I am working from it when I give you suggestions.

[YEROC37]

Re: Magnavox 32md359b/f7 White Screen and with sound only

On that first Pin I get nothing....from top of TV down starting with first pin on power board I get 0volts

[tom66]

Re: Magnavox 32md359b/f7 White Screen and with sound only

My guess is then the main/digital board, which is where troubleshooting gets tricky.

Although I never asked, but what is it in standby? Some TVs use inverse logic where a high signal indicates backlight off.

[YEROC37]

Re: Magnavox 32md359b/f7 White Screen and with sound only

stanby? The backlight is on and I can see light light shadow of menu selection as I make selections

[tom66]

Re: Magnavox 32md359b/f7 White Screen and with sound only

What I mean is, what is the pin you are testing measuring when the TV is off (in standby mode.)

[YEROC37]

Re: Magnavox 32md359b/f7 White Screen and with sound only

No voltage on either pins

[tom66]

Re: Magnavox 32md359b/f7 White Screen and with sound only

So it would appear to my limited eye that the main board isn't switching on the backlight (or it is switching it off quickly) which is unusual. Can you post a picture of the connector you are testing, I need to double check it is being tested properly.

[YEROC37]

Re: Magnavox 32md359b/f7 White Screen and with sound only

I hope this helps, I placed testing probe next to pin slot I'm testing

[tom66]

Re: Magnavox 32md359b/f7 White Screen and with sound only

Oh, I didn't expect that. I thought it would be some kind of multi-wire connector but it's flat flex.

Can you see an R1035, or R1036, or Q1005 on the top side? They will probably be near that connector you have been probing, on the inverter side.