Struggling with my PSI23SGNABS to keep temperatures

[Newdl]

Hello and thank you for your time and attention,

I have a GE Atrica PSI23SGNA BS and it started getting randomly warmer (like roughly 16/41) then normal again (0/37) about 3 weeks ago. Eventually after a few days this became more of the higher temp than the now correct temps.

I emptied the fridge/freezer and opened the back freezer panel to the evap coils and found some ice. I defrosted and installed a new heater as it looked burnt out and didn’t pass continuity test. I verified new new one worked both testing and visually seeing it turn on. I have a new defrost thermostat and temp sensor I can install but the current ones seem to be working. When it did start back up I noticed the evap coil did frost from the bottom up and not all at once. The top 2 lines never got frost on them so I recharged the system with more R134a. The pressure now hovers between -1 and 0 depending on the cycling of the compressor (I think).

The fan for the evap coil sounds/feels like it is running when I push the door switch and the fan for the condenser coils is running. I don’t know if they are supposed to have a 2nd stage or not but they are moving.

Freezer still at 12 fridge at 41. I have cleaned the coil as best I can (is it in a cylinder shape so hard to clean) with a vacuum and compressed air and checked the main control board for burns or obviously failures. I see nothing. 

I am trying to determine if I am missing something or if this fridge is not worth repairing.

Beyond this issue it is in wonderful condition.

I am happy to post photos or videos of anything that may help.

Once again, I appreciate anyone’s time who has the opportunity to reply.

[Slav]

The evaporator coils should be evenly covered in frost. Since it's not, the sealed system may be low on refrigerant, or has a restriction. In your case possibly traveling/temporary restriction like debris or air due to a leak on the LOW side.

Also, the condenser fan may be too weak. Move your fridge away from the wall and put a small fan pointing towards the condenser. See if helps the frost coverage on the evaporator. If it does, replace the condenser fan motor.