Need help with Subzero 642S refrigerator

[boss96]

Hi guys, I'm fairly new to the appliance side of things having been a tv,audio, etc, tech most of my life. I've been branching out into the appliance side for a little while now.
Anyway, I have inherited a repair from a previous tech that has a recurring problem with temp control. Apparently it won't get cold enough. I had gone along with him to watch at one point where we replaced 2 thermistors mounted behind the cover inside the refrig side. He also went back and changed the control pcb. So at this point I'm not sure where to go with this one, I don't know if the evap. is freezing over or not.
Would anyone have a serv. manual with trouble codes and so on available?
Thanks for the help
Bob

[dentdaddy]

Is your evap fan running properly? Condenser fan? Condenser clean? I've had several recently that just needed the condenser coils cleaned. Have you checked your frost pattern on your evaps?

[boss96]

I need to schedule a house call and want to be as prepared as possible. I will indeed check the fans as I understand how they would cause the problem. I'm not sure about how to check the frost pattern, what am I looking for and what does it tell me?
Thanks for the reply

[tgoods]

Subzeros are notorious for their leaking evaporators.  You will see a large chunk of ice at the evaporator inlet and not much frost.  There is a five year full warranty on the sealed system and twelve year part warranty. Subzero recommends replacing the compressor whenever there is a low side leak on a 134a system.

[boss96]

Ok, I went out there yesterday and did some checking. On top of the unit where the 2 compressors are located I found condenser fan was not turning, I gave it a "push" and it started working. So now the motor is on order and I will be going back. The only thing I noticed is the condenser coil is right up against the fan and I would think it has to be moved so I can get to the bolts holding the motor to replace it. We'll see when the time comes.
Thanks for the advice guys, it really helped.

[dentdaddy]

There's four 1/4" screws in the bottom of the fan motor. Difficult to remove, but has to be done. Clean your condensor before installing new motor or you'll blow dust all over the kitchen.

[boss96]

Thanks, I saw those screws and thought maybe i could slide the motor out. I imagine you have to take off the fan blade to get it out though?