Kenmore 417.42142100 washer Strange Spin Behavior during Rinse Cycle

[sdnyer]

Greetings,   

This is a Kenmore branded Frigidaire model(417.42142100) front load washer.   Recently it has started acting strange during the rinse SPIN cycle where it exhibits the following behaviors

• First Rinse Spin Cycle does not stop.. just continues running until I manually advance the timer.
• Last Rinse Spin Cycle does not start and the appliance just sits there with the pump running.   Manually advancing the timer to the next stage allows the cycle to complete.
• All other cycles appear to be working as expected.

Things that I have done.

• Ran the speed control board tests and motor tests as specified on the wiring sheet.  Tests pass.   Noticed after the fact that you can measure the resistance across the Tach on the motor which I did not complete(I suspect this is prob OK)
• Checked the door latch/switch.   The wax motor for the door lock did not work so I temporarily connected the 2 contacts inside the switch that the wax motor would normally close to "fool" the machine into thinking the door is locked so the spin cycles can run..  The machines behavior did not change after doing this.  Only adults in the house so not a safety issue.
• Checked the timer contacts to make sure they were clean and not burnt.  Timer appears to be OK.

Looking at the timing/cycle sheet I see that the timer motor is not powered on all the time and periodically gets power to advance the timer from speed control board based on the other sensor inputs?  Could it be that closing the c

Not sure what all else to check at this point in time??  Appreciate your help.

TIA!!

[Ashton]

If the washer fills, agitation, spin and drain fine, but you need to bump the timer to advance. Replace the timer.

[sdnyer]

Found an online document Electrolux 2004 Technical Training Manual which describes possible failures on this unit.    It states that the timer can cause interference and send corrupt signals to the speed control board as highlighted below.   I have a timer on order and will give it a try and will keep this forum posted.

PROBLEM: Cycle Not Advancing or Timer Stalling Symptoms Update on Tumble Action Washers

CAUSE: The root cause of washer stalling in cycle (timer not advancing) on horizontal axis washers is
electrical noise generated primarily by the timer contacts opening and closing which can interfere
with proper operation of the speed control board. At times, depending on ambient environmental
conditions, this electrical noise can cause the motor controller board to receive corrupt signals
and remain on “stand by condition” resulting in the cycle not advancing. By manually advancing
the timer to the next step in the cycle or by turning the washer’s power off and on, the electrical
noise is discharged and the washer will perform until electrical noise may happen to interfere once
again.

SOLUTION: To resolve this issue, three jumpers have been added to the current motor controller board to
reduce electrical noise levels around the microprocessor. Testing has proven this change to the
board significantly reduces occurrence of control lock-up. The motor controller board assembly
with external jumpers is Part Number 134306000, identified by an information label with the number
134058400 Rev C or 134258700 on it. The label may be yellow, orange, red, white, green, etc.
134306000 will replace the following part numbers:
131770700
131887601
134149200
If the SCU 134306000 has been replaced and the timer continues to stall, replace with SCU
131887601GE.

[Budget Appliance Repair]

@sdnyer sorry to tell you this but I hope you ordered that timer from Appliance Parts Pro or Repair Clinic that will allow returns because the timer isn't going to fix your problem.

Where in that service bulletin do you see it anywhere say to replace the timer to correct the problem?

The SCU (Speed Control Unit) is what it is talking about needing to be replaced, it gets it's brain corrupted and locks up doing the same mode over and over instead of giving the timer the single to advance.

The timer is almost never the problem on these units - it's the speed control board getting stuck in a loop and not finishing it's routine to give the timer the single to advance, (if the timer advances OK in other parts of the cycle where the timer motor is directly powered thru the timer contacts then the timer is not the problem).

During certain routines that the timer gives the speed control a binary code thru it's four contacts the supply the speed control with the code for each routine the speed control is then in control of doing what it was told and when it is finished it sends the power to timer motor thru the speed control board to advance the timer then the timer is in control of the timer motor again.

[sdnyer]

@Budget Appliance Repair  Thanks for your feedback and detailed explanation.  You are absolutely correct that the SB states the SCU needs to be replaced. 

I went with the timer solution prior to seeing the SB and was just sharing my findings.  Additionally, I marked the 2 spots on the dial where the issue occurs and it is always at the same exact spots.  Got it down to exact timing so I know when I need to bump the timer to finish a load.  This is why I initially suspected the timer.   

Based on your experience did you see the SCU reliably lock up at the same exact 2 spots on every wash??  The SB seems to indicate that it is intermittent based on electrical noise. I was trying to figure out what how what pins were supposed to be active on the timer in these 2 failure spots(minutes ~18 and ~31 of the normal wash cycle) but was not able to infer that from the timing diagram.  Quite honestly not sure how to read those.  At minute 18 the drain pump keeps running but the tub does not spin.  At minute 31 the spin cycle does not stop.  

While its probably a shot in the dark, I am hopeful that the timer is marginal and causing incorrect signals sent to the SCU.  I did perform all of the SCU checks as specified in the tech sheet and all resistances were as expected.  That said, that SCU could still be toast as it does have integrated circuits that are not tested through that procedure.

 

[Budget Appliance Repair]

It always stops advancing in the exact same spot because that is the spot that the timer sends the SCU a code to execute a specific function and at that the time the control of the timer motor is handed over to the SCU to advance the timer to the next step when the programmed function of the SCU has finished.

The SCU gets stuck into the endless loop doing whatever function it was told to do but because of the glitch it never ends doing this function and gets to the point of it program to send power to the timer motor.

None of the diagnostic steps will detect or determine this type of failure - knowing about this service bulletin and eliminated all other possible problems leave you with replacing the SCU

[sdnyer]

Thanks Again William.  Really appreciate your insights.

 Looks like its time to retire this machine as the cost of the SCU is cost prohibitive and not worth it for an 18yr old washer.   Its been a good run, but has also required bearing replacements twice during this time as the seals fail and ultimately damage the bearings.

[sdnyer]

Confirming that it was in fact the controller board   

Quick update which might be interesting for folks who are also good with electronics and soldering.

• I spent some quality time running connectivity tests on the SCU starting from the connector and learned that many off the pins from the connector to the board were open.   18 years of heat and vibration causes these connections fail.  In fact many of the pads were physically lifted from the board requiring me to run jumper wires.
• Many resistors were loose and had to be re-soldered.   The heat takes a toll on them.

After adding a few jumper wires and re-soldering the resistors I am glad to report that SCU is back in business .   Sorry no photos to show as this was an iterative process.

 

[Budget Appliance Repair]

Good job @sdnyer That's the first I've every heard of anyone fixing one of those boards without sending it to a board repair company.

[sdnyer]

@Budget Appliance RepairThanks for your help and for steering me in the right direction!  This was a fun but time consuming process.