Hotpoint FZA34G freezer not working

Evening all,

Wondered if anyone can shed some light on the above freezer problem.
The unit is not working, so I have returned it to my workshop to investigate.
The unit powers up, yet the compressor only kicks in for short intervals.
i.e. for 3-4 seconds, half a dozen times per minute.
I removed the display panel at the front of the m/c expecting to find a thermostat.
However, the only unit evident is a pcb/control unit.
I’m aware that these are difficult to inspect and test (especially for independent engineers!) and wondered if anyone could help, as I am inexperienced in the refrigeration field.
Also, would it be wise to attend a training course on refrigeration – if so, are there any establishments in Yorkshire? I am prepared to learn, and would consider full refrigeration engineering training.
Otherwise, does one try and learn along the way including using good text books (any recommendations) ??

Regards,

Jontymox