Choice vend cvc-224

I have a Choice Vend CVC-224. Up until recently it ran great. Then I noticed the compressor began cutting out but the condenser fan continued to run, never did this before, in the past when the comp. cut off so did the cond. fan.
Now the problem has progressed to the point that the comp. only ran for about 15 seconds and stops. I topped off the R-12 as I needed to last year when I aguired the machine but no change. I bypassed the cold control no change and installed a 3-in-1 starter booster today and it would run a bit longer, maybe a minute then the comp. cuts out. One thing I noticed is if I unplug the evaporator fan plug the unit will continue to run and the evap. temp will get to 30 degrees and falling, as soon as I plug the evap. plug back in, within seconds the conpressor cuts off again. If you continue to let it run the comp. kicks back on but only for seconds.
With the evaporator plugged in, at about 85 degrees ambiant, the High Side pressure ran about 125 psi and the low side ran about 37 psi, are these in the range?
I'm at a loss, am I looking at a compressor here? any help would be appreciated. Thanks in advance.. Denny