Mastercool model 69788 shows square blocks when turned on, what do I look for

Possible source - call them to request assistance.

https://indoorcomfortsupply.com/mastercool-pad-28x40x12-6500-for-adobeair-symphony-coolers-dpm220b-gpad220/

Possible similar model part diagram:
https://indoorcomfortsupply.com/adobeair-mastercool-hc64-a-h-parts-breakdown-list/

Saw several (but very limited) videos related to this online. All have indicated it as a problem with the control panel itself. I had a technician examine and that also was the conclusion with my own MC window evap not working. Fan would turn on briefly, go from high to mid to low on its own, then shut off. Lights woild also flash as it would toggle from each fan speed aling with oump going on then off on then off like crazy. I plugged the cable for the pump into an extension as indicated by one of thos very limited online videos and that has worked without any problems. My pump has been providing the needed water since doing that for hours. The fan blades however do not have a separate means to run without installing a control for the nlade speed it seems. So a delimna there. Changing the control panel costs about $100 for the part. Maybe the newer model part which runs $49 might work? The very limited videos that do nothing to show the process of how it’s done all show them installing their own control panel whether that is a turn switch or a thermostat system.

the solenoid is broken and it needs to be replaced, it also maybe a fuse with a relay unit all together in one unit. you will need a service manual,
www.manualsonline.com/
www.instructionsmanual.com/
www.manualsdir.com/
www.manualslib.com/
www.ask.com/
/mfg.name/make/model/service/manuals/dealers/parts/

try searching on line for a water dispenser manual rather than a water cooler manual

If the "blocking" of your screen appears to be a random pattern, you have a cluster of dead pixels, and it is best to replace the entire set (as repairs are unreasonably expensive). If you are seeing a black SQUARE at the bottom of the screen, turn off all closed caption and text options.

had this problem a few months ago, needed to replace the motor.

disconnect it from the duct via the screws on the underside. use a spirit level and screw it back on level. I would charge about $180 for this as a minimum callout and labour charge in qld

Go to the Mastercool web site:
http://www.mastercool.com/pages/vacuum_pumps.html
Pick out your model number and then click on "instructions" to download a manual. The most important thing is to change the oil frequently. This unit is used in HVAC to draw a vacuum on an evacuated AC system after repairs were made to insure it is free of any condensables.

Check the compressor relay (in the outside unit) Most likely it's stuck.

AC removes moisture from the air which helps us feel a lot more comfortable.  After you turned the AC off all the water that it took out from the air poured out.  Below are some of the reasons which may have caused it.:
Improper Installation Buildup of Ice inside the AC Leakage of warm air (warm air mixing with the cool air inside causes moisture to form) Blocked drain - you just need proper cleaning for this