• Please note, some of the links on our site are affiliate links (Learn More)

Speed Queen SWFT71WN trying to troubleshoot.


Nov 23, 2022
Model Number
Speed Queen
6-10 years
I have this commercial speed queen frontload washer (SWFT71WN) that stopped working. when you put coins in and press start and then it clicks a few times (like 30 seconds between each one) and then "Close Door" & "Final Rinse Spin" Leds start flashing. The panel has no digital display only knobs, LEDs and a start button. I called this national repair service and got the $69.99 diagnostic service. I tech comes out and tells me it is the door locking mechanism and would cost $370. I told him I would get back to him. I went online an ordered a brand new one for $40 and installed it myself in under 15 minutes. Super easy to do. That didn't fix the issue as it still did the samething as before. The door latch assembly has 2 functions: Check if door is closed (microswitch) and a sliding latch to lock it. I tested the microswitch for continuity and that was fine. I know the door latch works because it locks the door and you cant open it and it takes a couple of minutes after the LEDs start flashing before it auto-unlocks. Just to be 1000% sure the sliding latch part works I took the front faceplate off but still plugged into door latch assembly and tried starting it. I watched the latch engage and the little piece that pops out to prevent the latch from sliding back open. So I call the repair place back and tell them the diagnostic service I paid for was incorrect and to send the tech back. to make a long story short, they refused and I forced them to give me back my $69.99 -which they did.

Still left with a non working machine I decided to test the Hot n Cold intake valve because thats the next thing that should be happening after you press start. I checked for continuity and both were fine. I checked the screen and they were clean. the hoses weren't clogged either, the water pressure is in proper range. I removed the main controlboard and inverterboard and inspected them for any damage, blown resistors, capacitors, etc. using my USB microscope and they were visually fine. I am at a loss on what to check next and have a couple of questions:

1) If the pressure switch is faulty would that prevent water to initially flow into tub after pressing start?

2) Is the unbalanced microswitch normally open when washer functioning correctly and closed when load is unbalanced?

3) would a broken unbalanced switch prevent the washer from starting?

4) there is a two wire plug that if you jump them together it puts washer in test mode where you can advance through each phase (wash, rinse, final spin etc), but since it has no digital display Im not sure how to use that mode. Anyone know?

On a side note:
I looked up the flashing LED error code and it just said "mainboard communicatio error" which could be anything. I noticed on the schematic that it uses SPI for communication between both boards (MISO,MOSI,CLK,GND,VCC). Ive played around with JTAG,2Wire,UART on other micro controllers so I figured I might get a more detailed error code, then just those 2 LEDs flashing, if I sniffed the SPI traffic using my logic analyzer. I made a passthru cable and hooked it up, but the data I logged is just jibberish and not consistant. I think I have to mess with the clock phase and clock polarity bits in order to decode it properly. I havent used SPI so Im still trying to figure that out. I only mention this on the off chance someone on this forum has successfully sniffed the communication traffic on this washer or any appliance for that matter and can give me some pointers. I tried searching online but no one seems to be into this type of diagnostic debugging. either that or Im not looking in the right places.

if anyone can help it would be much appreciated. thanks in advance.
If you feel that you have benefited from this site, and would like to show your appreciation.