Re: Magnavox 42MF438B/27 - either shuts off completely or loses picture but keeps sou
Thanks all. Followed your advice and seems to be working fine again.
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Re: Magnavox 42MF438B/27 - either shuts off completely or loses picture but keeps sou
Thanks Martino. So you think the solder joint was loose and that's what caused it to burn? No need to replace whatever that piece is?
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Re: Magnavox 42MF438B/27 - either shuts off completely or loses picture but keeps sou
UPDATE
OK, so after nearly a year working well, this TV has developed a problem similar to the original. It doesn't power off completely, but the picture goes black while the sound stays on. This is usually accompanied by a burning smell and the back of the TV feels hot. Thinking it may be low quality capacitors used in the first repair, I pulled the back off the TV and noticed no obviously bad caps. However, the Power Supply Board has an obviously burned spot on the large component just...
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Re: Magnavox 42MF438B/27 - either shuts off completely or loses picture but keeps sou
FIXED! I went back and touched up the solders on a handful of the replaced caps. TV has been good for 2 weeks now.
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Re: magnavox 42mf438b/27
I am having problems with this same TV. Did you get yours fixed? Mine turns on and works ok for a while then will either power off and need to be unplugged or the back lights will go out but sound will remain.
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Re: Magnavox 42MF438B/27 - either shuts off completely or loses picture but keeps sou
Suggestions, anyone? Kids really miss their TV...
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Re: Magnavox 42MF438B/27 - either shuts off completely or loses picture but keeps sou
budm,
The INV_on measures 3.244 as long as the power light is on. The voltage doesn't change regardless of the screen's backlights being on or off, as long as the TV is getting power. When I press the power button to turn the TV completely off, it drops to 0 V.
Is the main board something I can fix or will it have to be replaced?
Thank you!
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Re: Magnavox 42MF438B/27 - either shuts off completely or loses picture but keeps sou
I found the pin labeled INV_on and measured with my multimeter. It measured the same whether the screen was lit or not (3.244 V). On the SSB, I noticed two green LED lights. They both stay on even after the backlights go out. Not sure if that is relevant, just thought I would mention it.
I took measurements of all the pins just in case (power was on but the backlights went out):
CN6
3V3 ST = 3.313 V
standby = 15.6 mV
GND = -1.7 mV
GND = -1.7 mV...
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Re: Magnavox 42MF438B/27 - either shuts off completely or loses picture but keeps sou
Ok thank you for the replies. I will try to test the inverter boards today. Is this something I can do with a basic $50 multimeter? Like I said, I'm very inexperienced with electronics...don't want to break anything or get fried. Thanks.
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Re: Magnavox 42MF438B/27 - either shuts off completely or loses picture but keeps sou
Forgot to add pics to original post....
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Magnavox 42MF438B/27 - either shuts off completely or loses picture but keeps sound
Magnavox 42MF438B/27, Chassis LC8.1U LA
The TV will come on and I can watch for anywhere from 5-30 minutes before either powering off completely, or losing the picture only (sound will still play). I would then unplug it and it would do the same thing after restarting. Usually, after the second time unplugging it and restarting, it would stay on. Leaving it unplugged overnight seemed to allow it to stay on longer.
I replaced all 22 cylinder shaped capacitors (although none showed obvious signs of failure) on the power supply board, but the problem remains. It actually...
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