I have Amana tandem 7300 washing machine and when I turn it on and set the cycle to normal it just beeps and says to add garment and when I go to open the door it's locked so I have to push power of f

Question edited for typo 'Tanden', not 'Tamden'.

Information on mainboard resetting in the link

https://howtodiscuss.com/t/amana-tandem-7300-washer-3-beeps/95090

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Am technician I need you support me voxy not working engine

The only reset is to unplug the machine from power for about 5 min's and if that fails you may need to replace the washer timer control board.

Sometimes this can happen when the power button does not return completely when pressed in. My cheap & cheerful solution was to use a bit of Blu-Tak on the button, so I could pull it all the way out.

It may think the door is open, front load machines will not proceed to fill if they cannot sense a locked door...

Pump blocked .down at front of machine water willcome out so be prepared with towels etc.clear blockage

It's a computer too. discommect it from power for 15 minutes and re-plug it. start initial setup again. Here is the link to the manual.
https://www.manualowl.com/m/Amana/NFW7300WW/Manual/206242tj3x46

It is possible that the machine does not start off the cycle because there are errors due to feedback from the inputs. For the program to start up the main program controller must initiate the INLET/MOTOR/DRAIN pump/ valve to open up and allow each function to be driven starting from the flow of water into the drum as also the drain valve to open to exit the water at the point of the program cycle. If this does not happen then the voltage at the valve/motor/pump must be checked or the fault relates to no voltage from the controller. This means the controller is a suspect.

If the water flows though the inlet then the flow pressure should be good, if not the inlet valve is bad or there is dirt in the filter. Also check the flow at the inlet of the water line. Once the water comes into the system the WATER LEVEL SENSOR - normally a pressure switch- must activate at the preset/chosen level to give the signal to the program controller to switch on the motor. What is most important for the motor to start functioning is that the door switch must be ON when the door is shut or this will be an error for starting the motor for rinse and wash.

Test a pressure switch: Click on : http://www.youtube.com/watch?v=HZZ2bDMspj8

Check this link to replace the inlet valve:
http://www.espares.co.uk/advice/washing-machines/a/7/1408/how-to-replace-the-inlet-valve-on-a-washer-dr.html

Why does my washer stop mid cycle an won't restart

Door won't unlock
Did all of the water drain out of the washer during the spin? Select DRAIN & SPIN to remove any water remaining in the washer. The washer door will unlock at the end of the drain.
Is the door locked and is the "Add Garment" light on? Press START/PAUSE once. The door will unlock.