ICON MC1648DLS ZC0549 Treadmill Motor Control Board Resistor Identification

Thread Starter

Tallen1750

Joined Nov 12, 2020
15
Have a MC1648DLS ZC0549 Treadmill Motor Control Board with what appears to be a resistor located immediately adjacent to the earth ground blade at R36. It's completely burnt out and unidentifiable. Does anyone know what this is? I want to try and purchase one and solder it in. Thank you.

IMG_7614.jpg
 

Thread Starter

Tallen1750

Joined Nov 12, 2020
15
Hi Everyone, I need some additional help with this board. Here is the background. Nordictrack 1750 treadmill. Belt would run for a split second and then stop. LED on motor control board would flash 4 blinks (bad controller)and other times 3 blinks (excessive current draw to motor). I ordered a new motor control board replacement pn#MC1648DLS (replacing original MC2100LTS-50) and installed the board. Motor ran for about 30 seconds and stopped. Same problem and same LED blinking. Motor tested ok with external battery but I replaced anyway being it was old. New motor installed and same problems encountered. I discovered the R36 resistor near earth ground blade was burnt out on the new board after the original attempt to run. I replaced the resistor and still have the same problem. I just took a voltage measurement at the A+ A- terminals on the board when selecting start on the treadmill. The voltage goes straight to 166vdc. It appears the board is sending max voltage to the motor immediately which causes the excessive amperage draw and the board to trip off and flash 3 led flashes. Does this sound remotely correct? If so, what component on this board controls that? Are there other things to test? If so, what? I'm an amateur at this stuff but refuse to let the problem win. Any help would be appreciated. Thanks!
 

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Dodgydave

Joined Jun 22, 2012
10,050
Q5 is a N channel mosfet, you will get a reading across the D and S terminals one way only on Diode test , if it reads both ways then it's blown . The same for the diode it should read one way only,.

irfp250m-pinout.jpg
 

MaxHeadRoom

Joined Jul 18, 2013
23,658
Did you try removing the load on the motor and see what happens, another indication to detect if the motor voltage ramps up or not, is to briefly place a incandesent lamp in place of the motor.
Max.
 

Thread Starter

Tallen1750

Joined Nov 12, 2020
15
Q5 is a N channel mosfet, you will get a reading across the D and S terminals one way only on Diode test , if it reads both ways then it's blown . The same for the diode it should read one way only,.

View attachment 222865
Q5 reads .002 both directions on D & S.
D2 reads .42 one direction and the other direction starts at .7 and ramps to 2.9 before OL (opening).
Both boards (old and new) behave similarly.
 

Thread Starter

Tallen1750

Joined Nov 12, 2020
15
Did you try removing the load on the motor and see what happens, another indication to detect if the motor voltage ramps up or not, is to briefly place a incandesent lamp in place of the motor.
Max.
Thanks. That's creative. I'll give it a try. Both my boards behave similar so I either have another issue on the treadmill causing issues or the old motor somehow burnt burnt something out on both boards before I changed out the motor.
 

Thread Starter

Tallen1750

Joined Nov 12, 2020
15
Looks like maybe the mosfet?
Did you try the motor on a automotive battery?
I have never really seen a bad motor.
Max.
Yes, motor runs fine on a battery.
What should a good mofset show for values during a test?
With regard to the mofset, IRFP250M is what this board has but not readily available quickly. Are there alternatives for things like this or must I stick with the same part number?
 

Thread Starter

Tallen1750

Joined Nov 12, 2020
15
Yep, Q5 is duff...
Any theories as to what could burn out a mofset on two boards? Along with replacing the mofset I need to figure out if it was the original motor or something else. Original motor appeared to run fine on battery just like the new one does.
 

MaxHeadRoom

Joined Jul 18, 2013
23,658
If motors operate identically on the battery , it does not point to any problem with the motor itself?
They are generally pretty sturdy.
Normally you should not see any voltage on the motor at first, not until the LED starts to flash steadily.
Max.
 

Thread Starter

Tallen1750

Joined Nov 12, 2020
15
Thanks for all the help so far everyone! Here is the latest. I replaced the MOSFET and reassembled the machine. It ran fine for about an hour and then the motor abruptly stopped again. LED flashing code replesented "bad switch". I tested the mosfett and it was toasted again. I then replaced the mosfett in the original MC2100LTS board, installed it, ran for 30 minutes, and smoked the mosfet in that board as well.

These MC1648 and MC2100 boards utilize PWM for speed control signal, correct? How does that PWM signal affect the mosfett if there is an issue on that end of the equation. What are the common reasons MOSFETs burn up? Any ideas what I should be looking for?

Thank you
 
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