old Hotpoint acting up

First time poster. Issue with cycling pattern. Old Hotpoint RT175DRW3. Cannot find this model in any data bank,so no manual.
Diagnostic is : result of freezer door accidentally not closing fridge was dead in the morning.Replaced defrost timer. Fridge worked.temp in both compartments good.
Unit ran for total of 71/2 hrs. befre cuttting out
Cycle was from start up: 2hrs 20mins ON --- 40 mins OFF ---55 mins ON --- 30 mins OFF --- 50 mins ON--- 45 mins OFF---!5 mins ON---- stopped and did not restart.
not sure where the the problem would be.
any suggestions would be greatly appreciated
thanks

is the evaporator fan ok? or heater? We had similar issue and it ended up been the evap fan seizing

You replaced the defrost timer?
Since you had the patience to record run cycles, my best theory is your defrost timer has failed to terminate it's defrost cycle. Use a flat blade screw driver to gently advance the timer's over-ride CLOCKWISE.