The unit will not turn on - Coby DVD-755 System

You may have a dirty coil so unit shuts off on high head pressure.
Turn unit off and clean coil

Sounds as if the control board took a power surge.

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Hello, there is a short to ground somewhere, check all the wiring from the inside un it to the outside unit and make sure nothing is touching metal.

Thanks for your detailed information. But solution is very simple. The compressor contactor in out door unit. Struck. And hence, when you power on, without indoor commanding, the out door starts running.

Replace same type Contactor relay (In out door unit) immediately. Hope, it's helpful.

There could be one or more problems with your notebook, a black screen could be a system board problem. Does the power light come on? If so turn unit off and unplug it, remove the battery and plug the power supply into the unit. Turn unit on. If the unit turns on it is a battery problem. If it doesn't power on then turn unit off and reinstall the battery and turn the unit, if you unit has a vga port on the side hook a monitor up to it and see if you get output. If you don't it is probably a system board problem.

your contactor that supplies power to the compressor has its contacts welded together and even if you turn up the thermostat and the coil that holds the contacts closed will de-energize,but with the contacts welded together this is no longer possible,you need to replace the contactor

Turn the thermostat off to see if the unit turns off. If it
does than you must have had a call for heating or cooling.

Put into heating mode let unit turn on, lower the setpoint and unit should turn off. If unit is not heating
than you have a problem with the outdoor unit.

Putinto cooling mode, turn thermostat all the way down, let unit start turn thermostat all the way up
if unit shuts off, unit is operating properly

Chances are your A/C unit can be repaired for a lot less than a new one -- I'd call for service.

The Mitsubishi units have to be reset by turning off the indoor units by switching the remote or thermostat to off. Then turn off the breaker to the outside unit(s). After 30 seconds,turn on the breaker and then you can turn on the remote for cool. If no lights come on on the inside units, most likely you have blown a fuse soldered on the main PC board. At this point, call your technician. A goos tech will be able to wire in an in-line fuse holder so if it should happen again, you can easily replace the fuse. If you do see a light or two come on at the indoor unit but the outdoor unit does not start after 3 or 4 minutes, sounds like you will need to call a technician. Most likely you have a blown fuse on the main PC board of the outside unit. It is not an easy one to replace. Good Luck!

You have a bad speaker on this unit or the audio output circuit is in need of repair. Try to disconnect all of the speakers and then turn on the unit. If it still stays in protect, you will need to have this unit serviced, unless you understand how these solid state circuits work. If the unit does come on without the speakers, turn off the unit and add one speaker at a time until the unit will not turn on. Disconnect that speaker and have it checked out or have the wiring checked out. Good Luck