Unit won't turn on

Interesting, sound like a failure of the button because most system either work with a greeg lit up led or fail with an amber or orange lit or flashing.
In this instance the amber could mean something has gone bad but the fact you can hold the button and have it boot up is strange.

Does the led turn green after holding the button for a while to let the machine boot?

regards,
mike

It may have a faulty compressor relay or overload, best to change both at the same time. It's either that or a bad compressor.

I’m happy to assist further over the phone at https://www.6ya.com/expert/david_dc2f9e0a44104720

Check with Lexmark to see if there is a reset button for unit

do the following steps: God bless you
To start test program, press and hold both POWER SCRUB PLUS and RINSE & HOLD program buttons, then turn unit on by pressing ON/OFF button. When program buttons are released, lights above them will flash. To end test program, press ON/OFF button.To check program indicator lights (POWER SCRUB PLUS, REGULAR WASH and RINSE & HOLD), press and hold each program button. When REGULAR WASH program button is pressed, CLEAN light also comes on.
To start testing, press both POWER SCRUB PLUS and RINSE & HOLD buttons a second time. When testing has ended and a fault was detected, the following indicator lights will be lit:
POWER SCRUB PLUS = Heater fault
REGULAR WASH = Water filling fault (over or under filling)
RINSE & HOLD = NTC (temperature sensor) fault ? note circulation motor stops shortly after it started during an NTC fault
To check for heater, high limit or flow switch problems, start testing until heating starts. Using a meter with a current coil, measure current going into dishwasher. If current is ~ 11 A, then heater, high limit and flow switch are OK. If current stays at ~ 1.5-2 A, then heater, high limit or flow switch are faulty.
If water level switch (f1) has failed (opened), REGULAR WASH light will come on and unit will continually fill and drain where testing won't be completed. If flow switch (e5) has failed (opened), water won't heat (to 150?F) and water won?t stop circulating. If NTC probe (f2/f4) has failed (opened), RINSE & HOLD light will come on immediately and testing will end shortly after water has started circulating.
If more than one fault occurs, more than one light will be lit.

The most likely failure (after a power outage) is your start capacitor or start relay. I would check them closely.

Generally speaking, an amp attempts to protect itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'nekkid'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech.

If you are talking about the indoor blower, you can possibly take the door off the air handler, make sure the door safety switch is pressed in, and try turning the blower wheel with your hand and see if it will start. If it binds up and still won't start, the motor bearings are worn and you will need the motor replaced. If it starts up, and runs for a while, you may have a bad capacitor. The capacitor looks kind of like a battery and is mounted to the side of the blower wheel housing. Be careful working with electricity, I hope this gets you started in to finding the problem. Mark

Generally speaking, an amp attempts to protect itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech.

Light's on mean you have power.

Initiate the self test program by doing the following -

To start test program, press and hold both POWER SCRUB PLUS and RINSE & HOLD program buttons, then turn unit on
by pressing ON/OFF button. When program buttons are released, lights above them will flash. To end test program, press
ON/OFF button.
To check program indicator lights (POWER SCRUB PLUS, REGULAR WASH and RINSE & HOLD), press and hold each
program button. When REGULAR WASH program button is pressed, CLEAN light also comes on.
To start testing, press both POWER SCRUB PLUS and RINSE & HOLD buttons a second time. When testing has ended
and a fault was detected, the following indicator lights will be lit:
POWER SCRUB PLUS = Heater fault
REGULAR WASH = Water filling fault (over or under filling)
RINSE & HOLD = NTC (temperature sensor) fault – note circulation motor stops shortly after it started
during an NTC fault
To check for heater, high limit or flow switch problems, start testing until heating starts. Using a meter with a current coil,
measure current going into dishwasher. If current is ~ 11 A, then heater, high limit and flow switch are OK. If current stays
at ~ 1.5-2 A, then heater, high limit or flow switch are faulty.
If water level switch (f1) has failed (opened), REGULAR WASH light will come on and unit will continually fill and drain
where testing won't be completed. If flow switch (e5) has failed (opened), water won't heat (to 150ºF) and water won’t stop
circulating. If NTC probe (f2/f4) has failed (opened), RINSE & HOLD light will come on immediately and testing will end
shortly after water has started circulating.
If more than one fault occurs, more than one light will be lit.

Let me know what you figure out. I can repair these boards most of the time.

possibly the thermal overload sensor failed internally? as indicated in the instructions there is a overload sensor and thay will typically fail in others appliances.