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Replacement parts for MAYTAG MDB8600AWW | AppliancePartsPros.com

Here is a service manual and a tech sheet
http://www.servicematters.com/m...ibrary/docs/16021814.pdf
http://www.servicematters.com/m...ibrary/docs/16026390.pdf

First make sure the units power connection is OK. Have seen a number of units where the wirenuts (if used) were not properly connected and finally caused problems.

Could be a bad door switch but from your description it is more likely a keypad problem. The tech sheet gives the procedure for checking the keypad using a meter.

Also very possible that it is just a bad ribbon cable connection.
Looks like the end of the ribbon cable just has some insulation removed. It can be cleaned using a pencil eraser. Do not use an ink eraser as it is too abrasive. The connector on the board can be cleaned using electronics cleaner or isopropyl alcohol and a tooth brush. Just be sure that all the solvent has evaporated before reconnecting.
Be sure to disconnect the unit from power when doing this.

If the keypad and the door switches check out OK then odds are high that it is the control board.

If you do not own a meter, I would suggest you purchase a one. You can get a decent digital multimeter for under $20.00. You do not need fancy though it is nice if the leads are a couple feet long.
If it saves ordering one unnecessary part it has paid for itself and you end up owning a useful tool.
Most places will not let you return electrical parts so if you order it, you own it.
A couple things to watch when measuring ohms and continuity
1. Always remove power from the machine otherwise you could blow your meter.
2. Always disconnect at least one side of any device you are checking. This eliminates the possibility of measuring an alternate/parallel circuit path.
3. When checking for closed contacts and continuity use the lowest scale (Usually 200 ohms). Then try higher scales. This scale is 0 to 200 ohms so if the device you are measuring is 300 ohms this scale would show an open circuit which it is not, you are just measuring outside the scale's dynamic range.

There is a good STICKY at the start of this forum about it's use.