Before you replace the main control board on a Samsung washer for "nd" error code
I have a Samsung front-loader (Model WF337AAW/XAA, 8 years old) that would intermittently not drain the water prior to the spin cycle, generating the "nd" error code each time. The problem occurred more frequently over a period of a week or so, and finally the washer stopped draining altogether. I first checked the drain pump / lines for clogs, etc. but found nothing, and as noted, it was working intermittently. I used the schematic on the washer (visible after I removed the top panel) to find the connections on the main control board that send power to the drain pump, put a multi-meter on the connections and started the spin cycle, but it read 0 volts (should be 120V to the drain pump).
Figuring it had to be "the board", I luckily found someone with a used board, same part number, for cheap on eBay, so ordered and installed it. That board allowed my washer to drain (!!) prior to the spin cycle, but the eBay board had a different problem that wouldn't allow the washer to spin up. No matter, now I knew my control board was definitely the problem, so took a closer look at it. Saw a row of 8 relays on the board, one of which is clearly labeled "drain pump". A failed relay (which is just an electrically powered switch) would definitely explain the symptoms, but how to replace it? All the parts on the board are swimming in 1/4" or so of hardened silicone sealant.
At this point, most anyone would just get a new board, but no local shops where I live had one in stock, and the online prices were around $250 for the board. Besides, I hate waiting, I love fixing things, and I had a "spare" board with a whole row of relays, most of which were probably good. I just had to figure out how to get past that silicone goop.
The main board and the display board are mounted in a plastic housing, back to back. And no WAY was that control board coming out of the housing; Samsung and silicone sealant had seen to that! Instead, I first removed the display board (held in place only by several plastic tabs), so now the housing (and of course, more silicone) was all that was in my way. After measuring and marking the approximate location of the row of relays on the back of the housing, I *carefully* Dremel-ed off a section of the housing, and pried it free from the silicone. Now I used a pencil-sized, pointed wooden dowel to cut through the silicone around the row of relays, front and back side, pulling the silicone off as I went, and finally used a small stiff plastic brush to remove as much of the remaining silicone as possible from the back side (soldered side) of the board.
I used a 12V power source and multi-meter to test the drain pump relay. Sure enough, no circuit was created on the load side of the relay when 12V was applied to the coil side. I checked all the other relays, and they were working fine. I HAD FOUND IT!! Feeling very confident now, I repeated the board surgery on the spare board, so I could get at those relays also. I used a soldering gun and soldering wick to free one relay, and carefully removed it from the control board. Cleaned off the remaining silicone sealant, fluxed and soldered it back into my original board, replaced the display board, and re-installed into my Sammy front-loader. Powered it back up, and miracle of miracles! I have a washing machine that works perfectly again!
So, not a repair for everyone (you'd need to have access to and be comfortable with a Dremel and soldering/de-soldering equipment), but it's totally do-able. If your washer won't drain, displays "nd" error code, and you're sure it's the board, this is an option. I Google'd the part number on the relays (F&T F3AA012E), and there were a couple of U.S.-based sources for purchasing them for less than $10/each.