Norcold Board Replacement

MJH071651

Member
I have a 2005 Norcold N621 that is showing odd displays and I have no control at the front board in the coach. Can't change the temp setting or mode. It usually just cycles. I was advised by a mobile repairman to replace the power board. I got the board kit that has both boards in it 633292. Both boards have been installed and there hasn't been any change. Same problems as before. Anyone know what to do? Please don't say replace the refrigerator becaues that's not an option for us.
 

wdk450

Well-known member
Besides the circuit boards, you just have the 12 volt DC logic power source for the circuit boards, the temperature measurement thermistor, and the board outputs - controlling the 110 VAC heating element, the boiler propane flame (and the ignition of the flame along with flame present detection on the same spark wire). I would suspect connections/wiring and would spray all connectors (especially the ones connecting the 2 circuit boards) with electrical contact cleaner like Caig Cramolyn DeOxIt. New circuit boards have been known to be defective. Dinosaur Electronics makes replacement circuit boards of a higher quality than the OEM boards, and offers some technical support. I would also measure the 12 volts supply to the back of the refrigerator from the rig. Low voltage can cause the circuit boards to shut down.

Here is a link to a Norcold refrigerator troubleshooting manual. Although this is for the Model 1200 series, these refrigerators are generic enough that this should provide you with some help. http://manuals.chudov.com/RV/Norcold-Troubleshooting-Manual.pdf
GOOD LUCK!!!
 

OnTheGoGA

Member
Agree, sounds like it could be a connection problem like was just said. Wouldn't be a bad idea to give The Norcold Guy a call or send them an Email. They've helped me with troublesome issues in the past. They give support and sell parts.
 

MJH071651

Member
I found my service manual online on a bryant website. There is nothing like this listed anywhere within it. The connections are all really clean. The board plugs were only disconnected to connect the new and since there is a tight seal I don't see how that could be the problem. The voltage readings are all constant even up at the front board. I was on Norcold Guy earlier looking over their technical blog but I didn't see any articles on this issue. I will give them a call in the morning
 

wdk450

Well-known member
When checking the voltage readings on both boards, did you use a ground point on the board in question as a reference for the voltage readings. I am thinking if you get NOTHING on the front panel board, there may be a ground return problem. BTW, does the interior light light up? That is a simple, direct 12 VDC lamp circuit routed from the main circuit board.
 

MJH071651

Member
No no, I'm getting power to the optical board. Clean voltage without any spike. The interior light works fine as well. The only thing abnormal is the front controls and it's not a connection problem. I left a message for Norcold Guy tonight on their chat window. Hopefully tomorrow they will be able to help determine the problem. I will post a reply tomorrow on whether or not they were helpful. In the meantime if anyone has anything else to check it would help!
 

MJH071651

Member
I got a response to my question early this morning from Norcold Guy. They wanted me to check for "AC ripple" on the inbound DC lines to the refrigerator power board. I didn't get anything coming up on my meter but I don't think mine can read millivolts. They recommended I connect an independent 12v battery direct to the refrigerator board. They thought right away that this was not a refrigerator problem and I was pretty confident they were wrong. :confused: A bit reluctant, we did this. Guess what? The refrigerator works perfectly with an independent battery. So, the issue is with my inverter and charger not with the Norcold. Thank you for recommending them! They're going to sell me a new inverter once I get the specs off the old one. :D

As I'm sure you can tell I am very pleased with them. Highly recommend using them for help and Norcold parts. I will use in the future if I ever need parts for the fridge:
http://thenorcoldguy.com/
 

cookie

Administrator
Staff member
I have a couple of questions.
Since your Norcold is in a 2005 coach has the battery ever been changed?
Have you checked voltage at the battery?
Have you had the battery checked?
How many volts did you see at the board? A good battery should be giving about 12.7 volts when the converter is idle and 13+ volts when charging. If you see the 13+ volts then the converter is working properly.
Have you checked all of the neutral wires to be sure they are tight?
Checked for corrosion at the battery terminals?

And I'm pretty sure you are talking about a converter, not an inverter.
These a just a few things to check before spending cash on a new converter.

Peace
Dave
 

wdk450

Well-known member
I got a response to my question early this morning from Norcold Guy. They wanted me to check for "AC ripple" on the inbound DC lines to the refrigerator power board. I didn't get anything coming up on my meter but I don't think mine can read millivolts. They recommended I connect an independent 12v battery direct to the refrigerator board. They thought right away that this was not a refrigerator problem and I was pretty confident they were wrong. :confused: A bit reluctant, we did this. Guess what? The refrigerator works perfectly with an independent battery. So, the issue is with my inverter and charger not with the Norcold. Thank you for recommending them! They're going to sell me a new inverter once I get the specs off the old one. :D



As I'm sure you can tell I am very pleased with them. Highly recommend using them for help and Norcold parts. I will use in the future if I ever need parts for the fridge:
http://thenorcoldguy.com/

Glad you got it solved!!

Usually, the big battery acts like a huge smoothing capacitor across the output of the converter/charger, and ripple isn't a problem. I would want to do a test on your battery with the converter disconnected, because I am wondering if it is acting like an open circuit instead of a filter capacitor.
 

MJH071651

Member
Yes, it's a converter/ charger. As for the questions on the battery, the battery was definitely not the issue. Keep in mind here that the only thing taken out of the equation here was the converter, so nothing else could be the issue. I hooked up one of my independent batteries direct to the refrigeartor and it worked fine. Also, you said the converter is good if it's charging the batteries at 13vdc. Not right. I got a better meter today and looked for AC ripple on the dc lines like they suggested. I was getting 0.8AC volts on my DC line. They said anything over half a volt of AC on the DC line can cause refrigerator problems. My batteries are 2 years old and working fine. I did a load test on them and they're able to hold charge properly. I have a new converter on order and will let you know how the install goes.
 
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