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My electric Roper dryer model res7745rq1 will not come on at all. I have checked the thermal cut-off fuse, non-resettable thermal fuse, high-limit thermostat, and the internal bias operating thermostat and they all test closed. I have continuity across my heating elements.
The door switch clicks when opened and the start button resets (clicks and works as normal). I'm at a loss. Everything seems correct. What am I missing?
Also, before it stopped working the timer started acting up. I would turn the dryer on and it would stop a few minutes later. I could move the timer a little and it would start back with out pressing the start button. I learned that it seemed to be a certain point that I turned it to that would cause this problem so I just just stopped turning past this point and I didn't have any more issues until now. Not sure if this is related to the current problem or not. I did take the timer apart and cleaned all the contacts and tested for continuity across the various contacts after it stopped completely.
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Have you checked the power?
Try flipping the breaker off/on slowly a couple times. Sometimes you can loose half the line without actually tripping the breaker.
Check the voltage at the plug
L1 to L2 should be 240 volts
L1 to Neutral and L2 to Neutral, both should be 120 volts.
If OK
Unplug the unit and check the wires at the terminal strip in the machine to make sure none are loose or burned out
If OK
Check the power at the terminal strip.
Do this with the heater off and on.
[COLOR="Red"]Be careful as 240 volts is lethal !!![/COLOR] |
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I have checked the power and I am getting the 120V and 240V at the terminal block. I did flip the breaker just to make sure.
Inside the dryer there was a schematic with how to test the timer and it passed all the test. The only thing I can think is maybe the motor is the problem. I'm going to take it out today and test it.
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Here are your parts Parts for Roper RES7745RQ1 Dryer - AppliancePartsPros.comSee the attachment for the wiring diagram that I am using as a reference. Hopefully it is the same as yours. [COLOR="Blue"] I am assuming when you checked the voltage you got 120 from L1 to Neutral, this is the moter drive side of the line. My electric Roper dryer model res7745rq1 will not come on at all. I have checked the thermal cut-off fuse, non-resettable thermal fuse, high-limit thermostat, and the internal bias operating thermostat and they all test closed. I have continuity across my heating elements.[/COLOR] Of all the above parts the only one that will effect starting is the thermal fuse on the blower. The rest of them are part of the heater circuit so should only effect the heat. [COLOR="Blue"]The door switch clicks when opened and the start button resets (clicks and works as normal).[/COLOR] Did you check this with your meter. Just because it clicks does not mean that it's contacts close. [COLOR="Blue"]Also, before it stopped working the timer started acting up.[/COLOR] This does point to the timer [COLOR="Blue"] I did take the timer apart and cleaned all the contacts and tested for continuity across the various contacts after it stopped completely.[/COLOR] The important contacts are BU/BK (timer switch 1) and T/W (timer switch 4). When you checked them did you have the wires disconnected from them? This prevents you from reading a parallel/alternate circuit path. Also did you get 0 ohms across both of them. Short your meter leads together before starting so that you can see if there is a zero offset in the meter. Check that the push to start relay contacts close when the switch is pushed. |
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Originally Posted by: denman 
I am assuming when you checked the voltage you got 120 from L1 to Neutral, this is the moter drive side of the line. YesOriginally Posted by: denman
The door switch clicks when opened and the start button resets (clicks and works as normal).
Did you check this with your meter. Just because it clicks does not mean that it's contacts close. Since I posted this I have been able to test the door switch and I am getting continuity on the door switch when the door is closed.Originally Posted by: denman
Also, before it stopped working the timer started acting up.
This does point to the timer I thought so to but I would like to know for sure before I just start randomly changing parts. I haven't been able to confirm that it is not working as it should. Originally Posted by: denman
The important contacts are BU/BK (timer switch 1) and T/W (timer switch 4). When you checked them did you have the wires disconnected from them? YesOriginally Posted by: denman
Also did you get 0 ohms across both of them.
Yes Originally Posted by: denman
Check that the push to start relay contacts close when the switch is pushed. The contacts are closing.
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The motor spins freely and I get continuity across the windings but that seems to be the only place. How else can I test?
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You could check 4M to 5M across the motor for 120 volts.
If it is there and the motor does not start it is toast.
I would unplug the unit.
Set the timer to mid scale of a timed dry cycle.
Attach (tape it on etc.) one meter lead to L1 at the line cord plug and leave it there. Now with the other meter lead work your way back through the circuit.
So BK and BY at the timer should be 0 ohms.
One Blue on the start relay should be 0 ohms.
Other blue on the relay should go to 0 ohms when the start button is pushed.
Following readings are done with the start button pushed.
Both sides of the thermal fuse should be 0 ohms.
4M on the motor should be 0 ohms.
5M on the motor should be around 1.5 ohms approximately (motor windings).
Timer switch 4 W should be 1.5 ohms.
Timer switch 4 T should be 1.5 ohms.
Blue on door switch should be 1.5 ohms.
White on door switch should be 1.5 ohms with door closed.
Neutral on line cord should be 1.5 ohms with door closed.
The above is the complete motor circuit. |
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I just tested the timer again based on your information earlier and I think I may have found something.
You said that T/W was important. When I check it I get 0 ohms only when it is in the wrinkle prevent setting. No other setting gives a reading. What does this tell you?
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Denman thanks so much for your help. The timer is the problem. I took the timer apart again to study it a little more and figure out how it works.
It turns out I was not getting a connection between T and W except when it was in wrinkle prevent. Upon close examination I figured out why. The contact on the end of copper was gone. I could see a hole where it used to be riveted. So the gap was now too wide to make contact. I soldered a small tit on the end and tested. My dryer now works.
Guess I will be ordering a new timer.
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I have had the little white thermal fuse act up, and check good and trip out just to come back on again
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