Some advice please.

Smallish floor mounted dehumidifier on casters, about size of a small
filing cabinet.

The colour and style of the overall unit suggest it was the sort of
thing sold by say Sears some 20+ years ago. (We also have a newer one
that is very similar but different colour and details).

Problem. Compressor runs but after a few minutes cuts out.

Problem has been tracked down to the compressor itself. It's a
typical fridge type sealed compressor. The compressor is marked as
follows;

"aose a" , "115 v 60 Hz", also "A5160A 144CG25". The compressor is
also labelled "Thermally protected".

After checking and bypassing all other parts of the circuit (the
humidistat, drip pan float switch and some sort of 'cut-out' clipped
to the output end of the cooling coils are all OK) it is found the
compressor runs but shuts down after several minutes without getting
particularly warm!

On the side of the compressor, plugged into two of the three pins
projecting from the sealed unit, is a typical compressor starter
relay marked [FSP] "920235" and "960A042-172" and "P4S".

Adjacent to the starter relay under the same cover and in series with
the hot lead from supply to the starter relay is a round bi-metal
device which the mounting clip presses against the outer surface of
the compressor. It is marked Klixon and "MR26ALK-3164" and "T.150-IK45
[FSP] 950234".
We presumed this circular device to be a bi-metal thermal protection
switch. However when it is temporarily by-passed the whole unit runs,
the cooling coils start to form frost but the compressor still cuts
out after a few minutes.

Is there another thermal protection circuit inside the sealed unit????
And if so there is presumably no way for a DIYer to fix it, nor would
it be worthwhile/safe to attempt. Correct?

We were going to chuck this unit but decided to give it another try
before doing so. Any knowledgeable advice would be most welcome.TIA.

BTW the unit is marked R12 (refrigerant) so if we dispose of it we
will call the Environment/Recycling people to determine where to take
it.

Although in one middle - eastern country where we were for several
years have seen car AC systems 'serviced' by letting the refrigerant
blow off and then recharging the whole thing!