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Frigidaire FWT645RHS0 - won't spin... inconsistent troubleshooting results.

12 posts in this topic

OK, this one is messing with my head a bit. Got a FWT645RHS0 with the classic "won't spin" problem.

I've read a bunch of forum posts, and have followed several versions of the troubleshooting flowchart, both in the actual wiring diagram for the washer, and a couple others online.

My results are incongruous with the troubleshooting flows. Here's what I've done so far.

-) run down all the typical issues with the pump - cleaned, tested, etc. Pump is working fine.

-) removed and tested the door switch assembly. All contacts are clean and close correctly. Wax motor reads 1.6ohms and bench tests fine.

-) motor tests fine (2.6ohms).

-) power to the speed control box. Pins 5-6 read 120. All good.

-) speed control fuse - fine. (It's opaque - I can't see the filament. Normal?)

-) voltages on 10-pin harness. Should read 120 on 2, 6 and 10. Should read 0 on pin 1 (and 9). It doesn't. It reads 120 on 2, 6 and 10, and reads 36v on pin 1 (and 9).

-) if voltages are not correct (they aren't... 36 != 0) ... check the timer contacts 1,5,7 C->B should be closed and 3 B->C should be open. They are.

So, the voltages being incorrect leads to testing the timer, which is correct, which means the voltages should be right, which they aren't. I can't find a next step to break out of this loop. If bad voltages are the result of a bad timer, but the timer tests ok, why are the voltages off?

-) resistance checks on the speed control 6-pin.

This is where the existing flowchart get thin on detail. When testing resistances on the speed control board, should this be done with the 10-pin connected and power on? Or with everything disconnected and power off (bench test)? I've done both. In both cases, the resistances measure way off from 3Mohm. They read open with power engaged, and about 400k on the bench.

My testing leads to a defective speed control board, but the weirdness along the way makes me hesitant to drop the coin on a new one.

It should be noted that at various points along the wash cycle, the motor will 'spasm'. It jumps for just a second, but not nearly enough torque to turn even the empty drum.

I'm open to any suggestions and hope for some expert clarification before I drop cash I don't have on a board that may not be bad.

Thanks!

G

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Need appliance parts? Call 877-803-7957 now!

even though the timer contacts showed continity they may be opening under the load .

Did you test for volatge at the speed control board with the plug connected or disconnected?

If plug was disconnected from motor control then that would lead to a bad wire possibly in which case you

would need to verify voltage coming out of the timer (at the timer plug) .

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... When testing resistances ... should this be done with the ... power on?

... along the wash cycle, the motor will 'spasm'. It jumps for just a second, but not nearly enough torque to turn even the empty drum.

1) ALL resistance measurements are with power disconnected ... as mentioned in your meter user manual

2) sounds like a loose connection somewhere ...

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PatOff, thanks for the reminder... I've been writing software for so long I'm really rusty on all this.

appl.tech, thanks for the tips, which led me to a couple more test cases with the following results:

-) tested voltage at the timer, 2, 6, and 10 read 120, and pin 1 reads 40v. This is with the harnesses *disconnected* from the motor control box.

-) hooked everything back up everywhere. 2, 6, and 10 read 120, and pin 1 reads 0v.

Voltages read the same both at the timer and down at the motor control, and everything is pristine, so I'm feeling pretty good about the connections.

Any other ideas? You guys are saving me here, I have three women in this house checking in on me every 15 minutes! o.O

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If your suppose to have 110V on pin # 1 but have 0V and the plug was disconnected from the

motor control then it definitely sounds like you have a bad timer.

Double check the wire terminal (pin 1) in the timer plug to ensure it not pushing out of the

connector or not making good contact with the mating timer pin.

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AccApp wrote:

First rule: It's not the timer.

Second rule: It's probably not the timer.

Third rule: It could be the timer. But rule out all other possibilities first.

I have yet to replace a timer in a Frigidaire built f/l washer ...

I can't count how many SCU's I have replaced.

"If between pin 5 to pins 2, 6, and 10 reads 120 VAC

and between pin 5 to pins 1 & 9 read less than 50 VAC."

Defective speed control board.

could be a bad / loose solder connection on the Motor (Speed) Controller

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Part link for the speed control board ==> Motor Control Unit

If it doesn't fix it, return it for a refund! :blinky:

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OK Fellas, thanks for the help. Connections are all good and tight.

I'd like to follow up with another question. A helpful pal on another forum suggested the following procedure (which I hadn't seen before). This suggestion has me testing from the hot lead (6) on the six pin, not the common (5).

Do this
EXACTLY:

Program and start the washer in
Drain/Spin Cycle

Disconnect both the six and ten pin plugs from the speed control board

Measure the voltage drop between
Pin #6 of the six pin plug
and pins
#1-#2-#6-#9-#10 of the ten pin plug

If you have 120 VAC on any of those pins, replace the
Speed Control board

If you have any other reading besides 120 VAC, replace the
Timer board

Well, I realize this goes against the 99.763% true "it's not the timer" rule, but I read 15v on pins 1, 2 and 10, and 0v on 6 and 9. That's clearly his path to a new Timer.

Thanks for the links to repairclinic.com. I'll definitely be getting the part from there, once I'm sure which part to buy!

You guys are the best...

S

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Well, being thorough I took the timer out and inspected it. Didn't realize it was mechanical with no circuitry. I now understand why they don't go bad. (Probably only in cases of extreme wear and tear, or locations where humidity and corrosion risk are high, and really - how many people do 30 loads a day in a chemical factory?)

I've ordered a speed control board.

Thanks!

G

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I now understand why they don't go bad.

An unbalanced load in the machine can cause the tub to jump up and down and smash the timer to smithereens, seen it numerous times.

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But it's not the timer, It is the motor control board!!!!

I tell you that test for the four contacts in the timer never seem to work out correctly and it's always the motor control board even when the test for those four contacts come out negative.

The positions of those four contacts make up a binary code which the board receives and the software in the board than interprets that code and does a particular function as required by the code received.

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