Maytag Neptune Drying Center MCE8000AYW
Posted 16 February 2011 - 11:03 PM
I shut off the breaker that feeds the drying center in case the heating elements are energized with the upper and lower in the off state.
Are there any diagnostics that I should perform or conditions I should look for?
Any ideas of what could be wrong?
Thanks in advance, all help appreciated.
Posted 17 February 2011 - 12:25 AM
Or one of the Heater Relays on the Relay Board may be shorted.
here's the MCE8000AYW tech sheet
with Maytag's sorry excuse of a wiring diagram
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Posted 17 February 2011 - 10:29 PM
Posted 18 February 2011 - 01:06 PM
Samauri - no beer at work...
I have a couple more questions if you don't mind...
On the relay board connector J9 there are two wires at pins 5 and 10 that are associated with a relay or relays that connect L2 to the upper heater. You had mentioned that possibly the heater was shorted to ground or partially shorted to ground causing it to stay on after the unit is off or the relay could have stuck contacts. I understand how the relay being stuck would allow line voltage, L2, to get to the heater when the relay is not energized, but if the element were shorted to ground where would the line voltage come from to power the element if the relay contacts were not fused or stuck?
My question may give you a good laugh, but I have been told since I am dumb I have to be tough. I may be missing the jist of your suggestion, but really appreciate the help. I hope to dig into this thing tomorrow and poke around and see how it works. Any idea if parts are available for the drying center? It seemed to have a short lifetime on the market.
Posted 18 February 2011 - 01:23 PM
looking at the wiring diagram again
. . but if the element were shorted to ground where would the line voltage come from to power the element if the relay contacts were not fused or stuck?
L1 goes to one side of the Heater Element through the Motor Centrifugal Switch (but only if running on this model)
and if any point of the Heater is grounded = heat
OK, most other Electric Dryers are wired a little differently.
Wouldn't cause your heat problem on this model
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Posted 20 February 2011 - 11:48 PM
Prior to opening up the unit I made sure everything was cool and then energized the breaker at the circuit breaker box to feed 240 VAC to the unit. I had the upper and lower doors open to see if the door switches being open would have any effect on the heating element operating on its own. Even with the upper and lower doors open the upper heating element still got hot with the dryer functions all turned off. I waited until I could feel heat in the based of the upper drying center and then shut off the power at the circuit breaker.
I removed the control panel
I removed the front cover and then removed the relay board.
There was a lot more lint than I expected in the bottom of the chassis so I removed all of that as well.
I also noticed that the duct on the front panel that connects the lint catcher to the exhaust had some wires trapped between the duct and the foam ring. No wires were damaged and the wires clearly made an impression on the foam ring. Not a big deal.
I noticed that the connection points on K6 are slightly discolored on the under side. The clear varnish over the bottom of the board is slightly brown. This is the relay that feeds L2 to the upper heating element through pins 5 and 10 of connector J9. I checked across the relay contacts with a volt meter on the continuity setting and resistance setting but there appears to be no continuity across the contact with the relay coil not energized.
Also the C15 solder joints on the underside of the board are slightly darker than other joints but not sure if this is normal.
I plan to run power across the relay coil tomorrow and make sure it acts normal. I'll also dummy 120 VAC to the hot side of the relay contacts and measure output on the closed side of the contacts without the relay coil energized and with.
So it appears that if the wiring from the relay board to the upper heater element is not compromised and the relay (K6) that feeds the upper heating element operates correctly under test conditions then the relay board and wiring are not the issue. I guess I would reassemble the unit (after getting rid of all of the lint and then plug the unit back in and measure the voltage output of the logic board (J6 pin 6) which energizes the coil of relay K6. I guess this would tell me if the logic board is giving an errant signal to energize the upper heating element. Can I use a Fluke 77 volt meter to measure the 12 VDC output on the logic board to see if it is calling for heat when it should not?
I'm not appliance repair man as you can see. Am I missing something obvious here?
I noticed on the schematic as mentioned by Reg_ above that it appears that the lower heater cannot be energized unless the blower is running but the upper heater element can be energized as long as the thermal fuse and high t'stat are in the correct state regardless of the operation of the blower motor. This assumption only holds true unless the logic board is designed to make sure the upper heater cannot be energized unless the upper blower motor is running, then in my case the logic board is not doing its job. Does this logic or feeble attempt at logic lead toward a logic answer to what is wrong? Logic board?
Admittedly this is sort of fun until my wife wants to do laundry, then it needs to be fixed or I'm looking to borrow a dryer.
Thanks for your help...
Posted 21 February 2011 - 12:09 AM
You can fax the schematic to me at 866-315-4504.
Posted 25 February 2011 - 09:52 PM
With the 120VAC applied to the com side of the contact and no DC voltage across the coil there was no voltage on the NO contact so it appears that neither contact is stuck closed.
I cleaned up the rest of the large quantity of lint and partially reassembled the dryer. I left the console/control panel loose and turned on the breaker, but left the upper and lower dryers in the off state. At this point I checked the output terminal from the logic board that controls the K6 upper heater relay and the output was at 0VDC as would be expected with the upper dryer turned off.
Everything seemed to be working properly.
I shut off the breaker, completely reassembled the dryer and then turned the breaker on. It works now as expected, it no longer heats the upper element when the unit is turned off with the breaker turned on. It also still drys laundry.
I can't explain it, but it works now. Maybe it was all of the lint on the boards and everywhere else.
After all of this I realize that the heating elements are no longer manufactured so if one of them goes my wife will loose here drying center.
Thanks for all of your help.
Posted 26 February 2011 - 11:46 AM
Posted 14 November 2011 - 11:13 PM
To divide the problem into pieces somewhat I attached a T-tap along the brown wire associated with pin 6 on the J6 connector on the logic board behind the front panel. Pin 6 on J6 is the wire that provides 12 VDC to the K6 relay on the relay board to provide line voltage to the upper heating element. I connected a long wire to the T-tap and ran it out of the front of the dryer via the front control panel/side pane interface/gap. I made sure it was not pinched or that the insulation was compromised. I turned on the breaker and immediately the upper heater element began to tick as if it were energized and then it started to get warm. At this point I had both upper doors and the lower door open, no elements should be energized. I checked the voltage on the wire connected to pin 6 on J6 relative to ground with a fluke volt meter and found that there was 12 VDC present on the wire at pin 6 on J6.
Then I turned the breaker off in the breaker panel and removed the membrane switch panel connectors from the logic board for the upper dryer, J2A, J2b. I turned the breaker on and the upper element began ticking as if it were energized and the wire attached to pin 6 of J6 was at 12 VDC relative to chassis ground.
I shut off the breaker and then reconnected J2A and J2b and then turned the breaker back on and ran the upper unit to make sure it still worked and it did. I noticed while the upper unit was running that the voltage on pin 6 of J6 relative to ground was nearly zero, but the air was warm inside the dryer.
Is there any way to tell if it is the logic board or if it is the membrane panel or something else that is causing the heating element to continue heating?
Any ideas on how to determine which component is causing the upper heating element to remain energized even with the doors open?
Yes, I realize the dryer is getting old, but my wife raves about the upper drying center for drying sweaters and delicates so I prefer not to replace the drying center with a new standard dryer.
Thanks in advance for any ideas or help.
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