Magnavox 30MF200V/17 Won't Power Up

[kevinm34232]

Re: Magnavox 30MF200V/17 Won't Power Up

? I dunno there is another line that has about 160VDC but this particular line has 85V standby and jumps up temporarily to around 315-320VDC before it shuts down.

[tom66]

Re: Magnavox 30MF200V/17 Won't Power Up

The service manual states 288V should be what 400V_HOT measures... I think it's limited by capacitor 2804/2803.

[kevinm34232]

Re: Magnavox 30MF200V/17 Won't Power Up

I got the new standby/audio board from SJ and still same problem. Ive got so much time and money in this old TV now it's war.

I just want it to work so I can throw it out the window afterwards.

[kevinm34232]

Re: Magnavox 30MF200V/17 Won't Power Up

If Im getting 5V at the SOST pin of control IC7001 MC34067P, does this indicate a problem with power board or somewhere else like backlights?

At this point I'm all in with this one.

[tom66]

Re: Magnavox 30MF200V/17 Won't Power Up

I believe SOST should be high for it to work.

[kevinm34232]

Re: Magnavox 30MF200V/17 Won't Power Up

I think after all this time it may be a bad Darfon transformer on the inverter. I had just given up on this one and was tearing it down for parts, when I noticed the 4006A transformers on the inverter board under the shield. One of them has open secondary. I ordered it will see what happens.

No 2 seconds to black just would do green led for a second then back to red.

[tom66]

Re: Magnavox 30MF200V/17 Won't Power Up

There could be an error feedback signal from the inverter, but I've only seen that on Sony, Panasonic and Sharp sets.

[kevinm34232]

Re: Magnavox 30MF200V/17 Won't Power Up

This is the board. There is a single wire connection that goes from the circled connector into the panel but other than that looks typical.

[tom66]

Re: Magnavox 30MF200V/17 Won't Power Up

That appears to be the ground return for a different CCFL bulb drive design, I have seen it a few times before. Not often though.

[Peter Chiu]

Re: Magnavox 30MF200V/17 Won't Power Up

took out the ballast board, couldn't find any problem, put it back ,now is working.

Probably bad connection.