I'm seeking assistance with an ongoing issue with my Zephyr beverage cooler (model PRB24C01BG, Serial: 1016588LQF).

The unit will cool normally for several hours, dropping from ambient temperature (around 73°F) down into the low 60s, but then the compressor shuts off unexpectedly, and the display reads “HI.” The temperature then rises. The compressor is warm but not excessively hot at shutdown. When the door is opened, the compressor restarts and cooling resumes, but the same cycle repeats.

To rule out common causes, I have completed the following troubleshooting steps:

1. Confirmed the “R” indicator/light remains on (unit indicates it is calling for cooling / compressor operation)
2. Confirmed there is no ice buildup on the evaporator coil
3. Moved the unit into an open space with improved airflow/ventilation to rule out overheating from restricted airflow
4. Replaced the compressor relay
5. Replaced the compressor starter/overload
6. Replaced both cabinet temperature sensors with new OEM Zephyr sensors
7. Performed a door magnet/switch test using an external magnet (including with the door fully sealed) to rule out a faulty door switch or door magnet
8. Performed a multimeter compressor ground/continuity test (no prong-to-shell short; compressor runs and cools before shutting off)

Despite these steps, the issue persists unchanged.

At this point, the only remaining component I can identify is the main control board, but it looks fine. I would appreciate any insight into whether this symptom pattern aligns with a known control board issue or another concern.

may be overlooking