Whirlpool Duet Dryer Repair

Our Whirlpool Duet Dryer stopped working. Lights would light up, but pressing the start button would cause a "F01" error code. Turns out the dryer comes with a troubleshooting manual, which was in a pocket attached to the inside of the lower front panel. 

Very thorough

The recommendation for the F01 error code was replacing the main board, which is expensive. I followed some of the other troubleshooting steps, particularly for the motor, since that wasn't starting. The control board is accessible by removing 3 screws in the back and sliding the top of the dryer towards to back and off.

Main control board. I took pictures of all of the
cables before disassembling.

One step had me measure the resistance across two pins on the main board, which came out to ~2 Ohms, meaning they were shorted. The recommendation was then to replace the main board. Using the circuit board and the circuit diagram, I figured out that that was measuring across the motor power relay. The relay also smelled like magic smoke. Ah ha! Relays have a limited life span, and after some googling, I found out that this relay often dies in these dryers: youtube link. 

This relay smelled toasty.

Control board was held in with one screw and
had tabs that slid out of slots in the sheet metal.

I used popsicle sticks to push back the 6 plastic tabs holding the control
 board into the plastic carrier, which then allowed me to pull the board out. 

Yup, motor relay let out the magic smoke...

This dryer has an AC power relay, and I'm guessing it has logic to not close the power relay if it detects a short elsewhere, which was likely why the (DC) controls seemed to be working, but the motor and heater were not. Anyways, the motor relay is a strange package, so I had to find an exact replacement: Omron G8P-1A4P 12VDC 30A 250V. Unfortunately, they don't make them anymore, but there seems to be ample stock on eBay and Amazon, along with some non-Omron substitutes. When replacing relays, make sure to get the correct coil voltage (the 12VDC) and at least the stated power ratings (30A, 250V). If I hadn't been able to find this relay in this package, I would have bought one with the same specs and used wires to solder to the correct pads.

Luckily this relay is through-hole, so removing it was easy using a solder sucker. Unfortunately, the death-throes of the old relay burnt one of the pads. I could still sort of solder to it, but the connection to the trace was poor, so I added a wire to take some of the current. 

Replacement done.

It lives!!

I reinstalled the control board, and powered up the dryer for a test: it worked. I took the opportunity to vacuum under and in the dryer while the panels were off, then reinstalled the panels. 

Total cost was $14, maybe 2 hours total of my time. Replacing the control board would have easily been $400, and I don't want to think about how much a new dryer costs these days. It pays to know how to fix things.