Viking dfsb483d not cooling

[Frank P]

Woke up this morning to a thawed freezer. Compressor wasnt running after doing some research I got to the relay board and tapped the compressor relay and it kicked on along with the fan.  Still not getting cold.  Got to coil in freezer only the top part where cap tub enters has some frost on it.   Measured low voltage going to inverter from mother board red to red and black to black getting -3.6vdc is this normal? I haven't seen a negative control voltage discussed anywhere in the forum.  Normally 4-6 vds. Compressor is an Embraco VEGY 8H. 

 

[16345Ed]

2 minutes ago, Frank P said:

Woke up this morning to a thawed freezer. Compressor wasnt running after doing some research I got to the relay board and tapped the compressor relay and it kicked on along with the fan.  Still not getting cold.  Got to coil in freezer only the top part where cap tub enters has some frost on it.   Measured low voltage going to inverter from mother board red to red and black to black getting -3.6vdc is this normal? I haven't seen a negative control voltage discussed anywhere in the forum.  Normally 4-6 vds. Compressor is an Embraco VEGY 8H. 

 

I’m guessing you had meter leads backwards explaining negative reading. 

Sounds like sealed system issue if entire evaporator not frosting. 

Edited August 12, 2018 by 16345Ed

[Frank P]

Had red on red  and black on black but not sure whats positive coming off of board just assumed red was positive. 

 what options do I have to diagnose the sealed system. Units been working fine since I got it last year. 

[Frank P]

Ok black is positive and red negative found in schematic.  So 3.6 v seems low compared to 4-6 which I have been seeing.