I bought this side by side fridge about 6 years ago. And in 2004 the adaptive defrost control board (ADCB) was replaced due to the the fridge not cooling (frost on the cooling coils). Now I have the same problem, the cooling coils are covered in frost causing the cooling issues. So I suspect it could be the ADCB agian. I tried testing the ADCB by shorting the L1 and Test pins on the ADCB and nothing happens. Shorting the pins is supposed to cause the fridge to shut off and when I short them, the fridge does not shut off. Does this mean the ADCB is bad? Also, I checked the resistance of the Defrost Heater and is reads O ohms. Not sure if this means it's broken. I heard that some of these heaters don't have any resistance and 0 ohms is normal?


Any help would be appreciated.


Rich

Hi Rich,

0 ohms is ok. Same for the defrost thermostat. Here's how I do it, there are only three componets to the defrost system. Check continuity through heater and terminator, if both check ok, replace adaptive timer. That's it.

Rick

__________________
SERVICE TECHNICIAN: BEEHIVE APPLIANCE....... 1985-1988
SERVICE TECHNICIAN: HANSEN REFRIGERATION. 1988-1998
OWNER/SERV TECH: RICK'S APPLIANCE REPAIR...1998-2001
SERVICE MANAGER:Used Appliance store..... 2004-PRESENT
ONLINE SERV TECH: ApplianceBlog.com ApplianceJunk.com
LINCOLN TECHNICAL INSTITUTE:..................... 1977-1979
CERTIFIED TYPE 1; TYPE 2.....REFRIGERATION SERVICE E.S.

ha ha I thought i was the only one who did that lol

Thanks for the help, I suspect it's probably the ADCB again.

The heater and Thermostat switch seem ok. I checked the continuity for the Thermostat and got continuity (0 ohms) when the switch was cold and an open when the switch got warmer. So I figured the ADCB must be bad. So I replaced the ADCB and the problem still exist. Two hours after replacing the ADCB the frost on the cooling coils is still present. So what esle could it be? Is it the defrost Heater ? Not sure how this whole circuit is supposed to work. I checked for 120 volts to the heater and I get 0 volts. Should the 120 volts be present all the time? and power gets to the heater when the Thermostat switch closes?


Need help


Rich

Rich,

Right now there is too much frost on the coils for the heater to ever get rid of. For that much frost, your going to have to use a hair dryer and defrost it. You'll have to make sure it's all defrosted or it will frost back up. Once you get it defrosted, the timer and heater will take care of it.

Rick

__________________
SERVICE TECHNICIAN: BEEHIVE APPLIANCE....... 1985-1988
SERVICE TECHNICIAN: HANSEN REFRIGERATION. 1988-1998
OWNER/SERV TECH: RICK'S APPLIANCE REPAIR...1998-2001
SERVICE MANAGER:Used Appliance store..... 2004-PRESENT
ONLINE SERV TECH: ApplianceBlog.com ApplianceJunk.com
LINCOLN TECHNICAL INSTITUTE:..................... 1977-1979
CERTIFIED TYPE 1; TYPE 2.....REFRIGERATION SERVICE E.S.

Rick, I understand what your saying, but it seemed like the frost got worst after replacing the ADCB. I had defrosted them yesterday and of course today they were frosted again but not as bad. I just got thru defrosting the cooling coils again, so I'll wait and see if they get frosted up again. I have the cooling coil panel removed so that I can monitor the frost.

Rich

Rich,

Is the frost uniform from top to bottom on the evaporator coils? The coils will frost up 3 to 4 times faster with the evaporator cover off. How thick would you estimate the frost is on the coils?

Rick

__________________
SERVICE TECHNICIAN: BEEHIVE APPLIANCE....... 1985-1988
SERVICE TECHNICIAN: HANSEN REFRIGERATION. 1988-1998
OWNER/SERV TECH: RICK'S APPLIANCE REPAIR...1998-2001
SERVICE MANAGER:Used Appliance store..... 2004-PRESENT
ONLINE SERV TECH: ApplianceBlog.com ApplianceJunk.com
LINCOLN TECHNICAL INSTITUTE:..................... 1977-1979
CERTIFIED TYPE 1; TYPE 2.....REFRIGERATION SERVICE E.S.

Rick- After I sent you the e-mail- I went and carefully checked the coils for frost and realized that there was a lot of ice built up toward the rear of the coils. Note that the coils are located inside the freezer on the back wall. So I completely defrosted it with a blow dryer. I powered up the Fridge without the cover for the coils so that I could monitor it. And within 1 hour I could see a thin layer of white frost already building up uniformily on the coils. So it sounds like I need to put the cover back on to slow down/prevent the frost build up?

Rick,

attached pics of coils after 1 hour of operation after defrosting. You can see there already is a light frost on them.

Attached Thumbnails