How to fix portable A/C unit

[TheGadfly]

So I found an IDYLIS portable air conditioner (#416710) on the sidewalk a couple days ago (there's a lot of move-out "garbage" on the streets of Boston these days). I've been on the market for a new unit for my apartment and this unit looked clean and relatively new so I took it.

I plugged it in and it seemed to work fine for about a minute. Then I realized why it was on the sidewalk:

When turned on, the compressor runs for about 30-60 seconds before shuttering to a stop (the fans still run continuously). After another 30 seconds, the compressor kicks back on. While the compressor is running, cold air is coming out of the unit and generally runs long enough to bring the room temperature down by one degree; however, soon thereafter the compressor shuts down and room-temperature air comes out. This cycle continues no matter how long I run the unit. The net effect is a near zero-degree difference in room temp.

Just to rule-out any obvious problems:
-The unit is plugged-in properly and turned to the correct setting
-The temperature is set to the coldest setting (68-degrees F)
-The unit is accurately sensing the ambient temperature in the room (usually about 80-degrees F).
-The unit is properly vented out of a nearby window and the rest of the windows in the room are sealed.
-The water reservoir is completely empty and I have a continuous drainage hose hooked into the back.

I took the cover panels off of the unit and didn't see any obvious problems. Both the condenser and the evaporator are clean (and I dusted them off for good measure). I didn't find any leaks or traces of oil. No apparent damage at all.

Could this be a control board issue? I also noticed that this unit has a temperature sensor on the evaporator. Could this (or another sensor I'm not seeing) be malfunctioning? I'm happy to change these things out (or remove them if the unit can operate without them) but I want to rule out any mechanical problems with the unit before I start swapping out circuit boards and sensors.

Thanks for your help!

[sisto]

It's most likely low freon or a control board problem. You could try checking the freon level and you may be able to find a manual for it online and see if there are any test points on the control board.

[Spork]

As much as I love the challenge of getting something cheap or free, fixing it up and getting it working... The first thing I would do is to shop for a similar AC unit new.  Window units are extremely cheaply built (and can often be pretty damn expensive to run).  It is often cheaper to buy a cheap ass $150 unit at Home Depot than to try to fix a broken unit.  They're semi disposable and often have a very short lifespan.

Probably the reason it was left on the side of the road is because there is generally a $5-20 disposal fee for freon-containing units.  Someone didn't want to pay to throw it away.

[TheGadfly]

Probably the reason it was left on the side of the road is because there is generally a $5-20 disposal fee for freon-containing units.  Someone didn't want to pay to throw it away.

I also considered this but I knew I was talking my chances.

The more I think about this, the more I'm wondering whether the vent hose is too narrow or has too many (i.e. two) bends to properly discharge the heat. Do you think this could be causing an overheating situation where the compressor shuts down periodically to avoid causing any damage?

Since the unit didn't come with a vent hose, i had to buy a 5" aluminum hose to discharge the heat. The unit also sits just below my window so there are two 90-degree bends in the hose. Do you think this is enough to cause the compressor to overheat?

I can't image this is the reason someone would throw away an air conditioner. Perhaps the compressor is overheating for some other reason?

[sisto]

I still think it's most likely low freon.