Treadmill Motor Speed Controller problems!

Discussion in 'The Projects Forum' started by ferris_beuller, Feb 3, 2009.

  1. maguiver77

    New Member

    May 8, 2011
    1
    1
    Hi Guys,

    So my treadmill wont start the drive motor. The up and down works and so do all the lights. I can go into the calibration mode and the motor spins and all the lights light up on the board except the cur lim. I am able to adjust the speed on this mode so im assuming the speed control works. WHen I take it out of TS mode the only lights on are D11 (12v). My TSing instructions says if " id D7 does not light but D11 does, it indicates a problem with the speed pot or wiring.

    When in calibration more I can speed up or slow down the speed by adjusting the pot. I reseated all the wiring. Any ideas?
     
    hankh68 likes this.
  2. armacnei

    New Member

    May 24, 2011
    1
    0
    Thanks for the schematic, really came in handy. I spent some time troubleshooting this speed controller board and it appears that I am having some problems with the optically isolated triac.

    Alex MacNeill
     
  3. Autonut

    New Member

    Nov 20, 2011
    8
    0
    See my recent post about a Sears treadmill controller board problem. It is because of this website and your post that I decided to take a closer look at what might be causing my motor from not functioning. My board is VERY similar to what you drew for the MC-60. My Di, D2, Q2 & Q3 are S or D4015L's and are 15 amp SCR's instead of your 20 amp SCR's on your drawing. Also your MOC 3052 is a MOC3021 on my board. otherwise things are pretty much similar. So far in checking the SCR's and MOC, I do not find anything suspiciously wrong. I want to thank you for the work you did and I will let you know what I find since I should be able to do that now with your schematic. I have two other chips, a LM 358N & a LM324N. My board I think is just a little simpler than yours as far as features. I am a little confused however on your label LED SCR Trigger. My U3 or U31 in my case, just goes to a diode and the other side of the diode goes to pin 7 of (Q1) LM324N, This is as far as I have gotten today. Does your board actually have an LED?
    Just Me/Lee
     
  4. srs41873

    New Member

    Jan 5, 2012
    1
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    I have a LifeSpan TR2000 HRC treadmill and a piece of the control board came off. I am looking for a schematic of the board. I would like to put it back together (if possible).

    Can anyone help with this?

    Also, I cannot find anything (even a replacement board) online.

    Thanks all.
     
  5. trolley1

    New Member

    Oct 26, 2009
    9
    5
    After seeing the interest in the MC-60 schematic that I posted some time ago, I decided to put together some notes that may help understanding the circuit and troubleshooting. If and when I get my hands on another MC-60, I will take some more voltage measurements at zero and high speeds and post them.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,198
    1,797
    Hello Tom,
    I had assumed incorrectly that you had gone inactive, as you had not posted for a few years. Thanks very much for posting your original schematic; it seems to have been quite helpful to more than a few people! I have not looked at your new document yet, but it should be an added boon for those with similar units.

    Since this type of treadmill board seems to fail so frequently, I'd started building an LTSpice simulation from your schematic; some of which I'd posted in this thread:
    http://forum.allaboutcircuits.com/showthread.php?t=62960

    Unfortunately, I did not have time to finish it due to lack of information before I had to spend some time in the hospital, and the computer where the simulation resides won't be available until late April. However, it's reasonably complete. If you have some time, I'd appreciate it if you would have a look at the schematic attached to my first reply in that thread, and perhaps verify the reference designators, as well as clarify some of the values which were not present in the original schematic?

    Thanks kindly for any help you're willing to provide.
     
  7. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    9,652
    1,110
    Hey Trolley1

    This idea is freakin fantastic.

    U know what I think, science this tread mill issue comes up every now and then ?

    Why not make this some kinda sticky thingy that can be accessed easily when ever needed. If this is a thread it will get lost in the midst u know.

    I am interested in this thing since I have 190V motor and some boards and I am thinking of making this circuit since ( i dunno it was u ) it was drawn and posted. I was very happy that it was re drawn and like I said I wanted to do some thing but am limited for being some where rural to the advanced world. :(

    I am willing to make this board since I have the major components and a scope too.:D.

    But I need some one to do and make a PCB for the sake of the forum so I can post the test results and some kinda trouble shooting chart.

    This way I can really put something back into this forum since I have taken so much. Eh!

    Mod's please consider this and do something abt this. We have more than capable members to give and help those who are lost.
     
  8. trolley1

    New Member

    Oct 26, 2009
    9
    5
    SgtWookie,
    Sorry for my absence. I was focusing on a new hobby of bowl turning. Your schematic looks fine to me. I know that there are component values missing on my original schematic and I can offer little to find out what they are. The MC-60 is buttoned up in a Radio Shack project box on my drill press and I am reluctant to tear it apart. I did go over my original notes where I would sketch up small portions of the circuit before I was able to piece them all together into one schematic. I found in these notes - the capacitor from U1(2) pin 6 to ground is C15 1mfd, the resistor in parallel with the diode connected to U2(3)pin 8 is 150k and not 100k, the resistor feeding U1(3) pin 10 is indeed 10k. Other very minor point - if my memory serves me right - all four of the indicator LEDs on the MC-60 that I have are red. That leaves a few capacitors and your guess is as good or better than mine. I could see that C9 and C11 might be the same value and back in the ancient times when I was designing, I tended to use components of the same value where possible for cost and simplicity reasons.
     
  9. Stoney

    New Member

    Jun 7, 2012
    7
    0
    Thanks for the circuit, I was given a faulty treadmill some time ago and just decided to repair it after 6 months in the shed, mine runs fine for 10 minutes then slows down and stops, turns out the cur limit LED is lighting, even if the treadmill is set to some speed (this one is PWM controlled, no pot). You can stop the motor by pinching the output flywheel with finger pressure.
    I brought the controller inside for further investigation, then found this circuit by fluke, joined the forums for a look. :)
    Will get the CRO onto it tomorrow, might replace C5 first, I suspect that since it can't be a true overcurrent condition then either the bias point has perhaps ripple on it or I have a dodgy LM324 to deal with ..

    will update later with results.

    Further work to do on this one, our mains is 240V and the treadmill is 110V, came with one massive isolation stepdown transformer, I am wondering what I would need to do to convert to 240V.

    Higher voltage rated SCRs, R14 and R9 changes spring to mind, I am not sure how this circuit will cope with much faster SCR on times .. I guess it should be fine.
     
  10. Stoney

    New Member

    Jun 7, 2012
    7
    0
    well mine is looking like a motor issue, i was getting around 100mV generated across the current shunt R28 and figured maybe it had gone high, from 0.01 up to 0.1 would exhibit my symptoms, I didn't have anything of that value around, so I shorted the R45/diode junction to ground, pinched the flywheel between finger and thumb while at 1 mph and promptly blew an 8A fuse on the primary of my isolation transformer.
    So the 10A current really was ..

    Motor resistance is only 1.2 ohms .. brushes look fine, someone above mentioned a motor resistance if 43 ohm but I can't see a 1kW 100V DC motor having an impedancea bove 10 ohm..

    hmm.
     
  11. mlightner

    New Member

    Jun 16, 2012
    1
    0
    New guy here, Firstly, many thanks to those posting on the MC-60 control bd. problems, and especially thanks to trolley1 for the schematic and other info contributed. I'm working on a MC-60 board problem, but I have the advantage of having a spare (working) board to compare between, On the bad board, the SCR TRIG LED is not lighting up when the console calls for movement, (but the SPD CNTL LED does light up. On the good board, when the SPD CNTL LED lights up shortly afterward the SCR TRIG LED lights up and the belt commences movement. I think maybe one of the op-amps on an LM324 IC is toast, because with a DMM set on diode junction test function, it gives me readings about 40 or 50% less than those measured on the LM324 on the good board (measuring pins 12-14) - would this be a valid indcation? I was thinking of trying a few comparative measurements with my infra-red thermometer, since I 'll have to 'order out' and wait for any replacement parts; anyone else had success doing that? Thanks for listening, and TIA for any help, Mike
     
  12. trini1

    New Member

    Aug 24, 2012
    6
    0
    Try replacing both the rectifer and mosfet the same time.
     
  13. Tzaddik418

    New Member

    Aug 30, 2012
    1
    0
  14. JimmyGourd

    New Member

    Oct 22, 2012
    2
    0
    Several have mentioned the "speed pot" in their posts (as does the instructions in the pocket by the motor and Tom's awesome MC-60 schematic). I have a simple question: Where is the speed pot? I found R31 (a pot with a slot to turn with a phillips screwdriver), but can't seem to locate the speed pot (seemingly a different pot per Tom's schematic).
     
  15. JimmyGourd

    New Member

    Oct 22, 2012
    2
    0
    Never mind. I forgot to look in the obvious place (on the console!)
     
  16. fredsantizo

    New Member

    May 12, 2013
    2
    0
    I need your help. Pls reply to fredsantizo@hotmail.com
     
  17. fredsantizo

    New Member

    May 12, 2013
    2
    0
    I need to control the speed of a motor with a MC-68. I will like to manage the speed of the motor with an Android phone. Can some one help me with the a way that I can interface this controller with the phone. Thanks for your time.
     
  18. efzauner

    New Member

    Mar 11, 2018
    2
    0
    This has been a great thread..
    I have a True treasmill with the SS90 controller. The MC60 schematic gave me great troubleshooting info. I did try to reverse engineer the schemeatic for the ss90 as well but gave up.. I just replaced every chip... took an hour... after spending days troubleshooting.. Works great again! sometimes brute force works best!
     
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