anhnga;2408633. said:
Some car can recovered this problem by put the main board of CMU to microware for 5 minutes !
Good God! DO NOT DO THIS! NEVER EVER PUT CIRCUIT BOARDS IN A MICROWAVE.
A microwave induces large electric currents to flow in the metal of all components, heating some components - like transistors to destruction There is no way of knowing the damage you will cause.
I would first suspect a connector; either to the CMU or inside the CMU. So remove and refit external connectors; if that doesn't work do the same with any on the circuit board.
If the fault remains you could try to look for a 'dry' solder joint. Dry joints look a little cloudy and less shiny than others. A small soldering iron could be used to heat and reflow the solder using some fine solder wire that includes a flux.
But whatever you do - DO NOT PUT ANY CIRCUIT BOARD IN A MICROWAVE OVEN - unless you want it well and truly fried!
To see what I mean take a small piece of aluminium foil and place that in the microwave; switch on and watch the fireworks.
(When WW3 starts the plan would be for all sides to set-off a bomb in the atmosphere above target countries to produce a large radiation burst, (microwave energy), with the intention of frying all electronic apparatus below. And remember in 1989 the Canadian power grid was knocked out for 9 hours by a geomagnetic storm.)