Vizio M70-C3, P602ui-B3, M80-C3,... Anyone fixed the main board?

[jason123]

Hi folks,
I'm seeing more and more of the P602ui-B3, M70-C3,... coming in with the same symptom: TV appears to turn on (front LED activity, fades off), but no picture, backlight or..

Replacement of the main board has fixed every one of these. These boards are becoming more and more expensive. boards warm up (heatsink fairly warm / hot)

The common issue is if you monitor a USB board connected to this main board, or the Optical Audio red light, i consistently seems to be rebooting after almost exactly 60 seconds (red Audio LED, and front LED go off, then back on shortly after)

I've had both the large Vizio processors under the heat sink reflow professionally (with board temperature measurement, and profile appropriate for the IC size / lead free) and no luck. I did this on multiple boards.

Anyone made any progress on repairing this board? suspecting bad EEPROM given the 60 second reboot / Watchdog triggering.

Any thoughts or experiences here?
Thank ou

[electroman5946]

Re: Vizio M70-C3, P602ui-B3, M80-C3,... Anyone fixed the main board?

It's a BGA chip problem . Reflow from back of th board.

[alfatv]

Re: Vizio M70-C3, P602ui-B3, M80-C3,... Anyone fixed the main board?

It's a BGA chip problem . Reflow from back of th board.

Why from the back?

[Gracchi]

Re: Vizio M70-C3, P602ui-B3, M80-C3,... Anyone fixed the main board?

I had the same mainboard problem that you detailed in your other thread, with all the same symptoms. I was able to repair the main board instead of replacing it.

I removed the mainboard, removed the heat sink, and re-flowed both chipsets with a heat gun at 400°C(750°F) for 3 minutes each. I only applied heat to the top of the chips, where they make contact with the heatsink.

This video was helpful for this particular issue,

[alfatv]

Re: Vizio M70-C3, P602ui-B3, M80-C3,... Anyone fixed the main board?

re-flowed both chipsets with a heat gun at 400°C(750°F) for 3 minutes each.
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This is a very bad advice including video, I don't see how proper temperature profile is followed.
Most likely it will be too little or too much.

[diif]

Re: Vizio M70-C3, P602ui-B3, M80-C3,... Anyone fixed the main board?

That's a good video for diagnosis but shockingly bad for the reflow. No preheating of the board, the smallest nozzle possible, movement that doesn't cover the whole chip and some weird pressing with a screwdriver, we don't actually see the chip move, that wasn't a decent reflow.

If the option is buy an expensive second hand board or to go for a heat gun reflow I say got for it. Lead free solder melts at 218c, keep some distance with that 400c heatgun.