my washer has been down for several months now and i have been in and out this thing and cannot diagnose what is going on. i have been on a couple forums but everyone seems to be stumped.

nothing happened that would lead up to having any sort of problem, it just stopped working and started showing f28 on the code list. i researched this and thought would be a simple fix, not the case. while running a diagnostic test, the test would not go any further than the door lock so i assumed that was interfering with the ccu and the mcu, so i changed the part. not the problem.

i have checked all the outputs of the ccu and everything is good. the only weird thing is that the neutral wire going to the mcu, while testing to the case, shows 80 volts for a second when starting a cycle. when checking for the power across the neutral and hot i get the full 120 volts. i also checked for the 5 volts dc and it is good.

on the mcu i checked the power and the 5 volts dc coming into it and it is good. i removed the mcu and did a continuity test on some internal components (part of a checklist i received) everything checked out fine.

i have ohmed the motor components out and it is fine also.

the only strange thing going on between the motor and the mcu is the grounding. i was checking my voltage to ground going into the mcu and when i was testing to the case it showed 120 volts and when i tried testing to the wire fastener in the case it showed around 80 volts. i scored the metal to get a better contact and it started showing 120 volts. this also increased my output of the mcu to ground when before it was only 80 volts. even though i am showing the 120 volts mcu output while testing to the case, when i test for the mcu ground output it jumps around and maybe hits 40 volts. the ground wire path goes from the case to the mcu, and then from the mcu to the motor (which is where i cannot get a good test) i tried a separate wire to ground the motor but to no avail. my big question is of the 5 black wires going to the motor from the mcu, are any of these a neutral? i checked a wire diagram and really couldn't answer my question. i know 2 of them are for the tach. i don't know about the other three. they are labeled u, v, and w on the diagram.

reason i ask is, it seems to me that if one of these is not a neutral then the ground is the return for the motor and without a good ground it will not operate. with the separate wire i used for the ground i was showing 110 volts output when checking to the motor case, but it still would not work and the f28 code came up.

can anyone shed some light on this problem

Hi bleonard:

Glad to see you resolved the problem with your motor by your finding that it was actually the motor control board not the motor. You seem to understand the test procedures for washer motors. Could you look at the problem I posted yesterday with regard to the E59 code (No Tach Signal in 3 seconds) I am getting. Did the tach circuit of your motor actually give the resistance values of 105 -130 ohms as specified in the diagnostic sheets?

Thanks

Joseph A. Stanko