Help with Motor Control Board - ProForm treadmill

[Crrose]

Re: Help with Motor Control Board

Ok got it. I have removed the board and will test it now. How bout the relay, what pins to I hook the battery to.

[selldoor]

Re: Help with Motor Control Board

but not quite sure where to place the probes.

Me neither budm is the man and the Bridge rectifiers I usually see have the contacts in line.
Anyway I think these are they on buds marked up board and it will do no harm
though will need to do again if budm says I have it wrong.
I would set meter on ohms 2000 and test DC+ to AC1 and note result
reverse the probes and test again - note result.
Then test DC- to AC2 note result - reverse the probes and test again.
Lastly test AC1 to AC2. This test can also be done on diode setting which some people prefer.

[Crrose]

Re: Help with Motor Control Board

I appreciate the encouragement. When I power it up LD1 LD3 and LD4 light up like they are supposed to. When I select a speed the PWM light flashes like it is supposed to. The incline motor works and it raises and lowers properly. I have pulled the safety switch out and power shuts off like normal and once reinserted I can turn it back on. I haven't tested the relay or the bridge rectifier yet. I'll remove the board to try that right now but not quite sure where to place the probes. I know there is continuity but not sure if that means its good or bad.

[selldoor]

Re: Help with Motor Control Board

Ok - I have been reading bits of the handbook
Does it have a motor to alter the incline? does that work?
Have you checked that the cutoff switch is pressed in as well as switching it on at the on/off switch?

Next time its all together or if you have already made a note can you record
what the leds do on the POwer Supply a,when you plug in b, when you switch on .

Back to the boards what I am thinking is that the repair people say there are only a few components that might have failed - two you have probably replaced so not many left - The relay is available and quite cheap to buy and between us I think we can test most of the replaceable components.
Perhaps have a rest from it then look back through the thread and make a list of tests then try them all again.
Were you able to test the relay with your drill battery if not and you have a problem doing that -just tell us. Same with the bridge rectifier - that is a static test with no power to the board - if you dont know where to place the probes - ask. If you can do those two that is another two (that are known to give up with age) less to worry about.
I know it is difficult to try and keep up when several of us bombard you with
different ideas - if you find that - just tell us you are doing it at your own pace, then report in every so often

[Crrose]

Re: Help with Motor Control Board

No other model numbers anywhere, it just has Pro-Form 785EX millennium drive, the control board is MC70 PN #124438 and power control board is PN #130857. I had checked on the sites Selldoor posted but since my problem points to the control board they want me to send it in for repairs and it is quite expensive. I got this treadmill for free and thought I could fix it so no loss if I can't. I can always remove the power board and motor and sell them and scrap the metal.

[selldoor]

Re: Help with Motor Control Board

@selldoor: it is a Pro-Form 785EX

Are there some more numbers letters after that - looks like a few variations
of 785EX

[keeney123]

Re: Help with Motor Control Board

Some things to consider if you by another treadmill. If this is a common problem what if it happens again. How much will a new treadmill cost and does it have the same functions. How does the cost of repairing it as opposed to buying a new one. The people that selldoor mentions seem to work with you and guarantee the product and explain the maintenance that needs to be done on a regular bases.

[Crrose]

Re: Help with Motor Control Board

@selldoor: it is a Pro-Form 785EX

[Crrose]

Re: Help with Motor Control Board

Sure makes things difficult when your not very knowledgeable about circuit boards. I am now getting 6.2v on DZ1 when the other night I got 6.2v then later 15.2v. Don't understand why it keeps fluctuating like that. I am also now only getting .5v from the red/black wires and 0 on black/white. Maybe I should just get another treadmill, I may be over my head in this.

[budm]

Re: Help with Motor Control Board

Info from selldoor is interesting since the repair modification is around that over heated area of those two diodes and the resistors.

[budm]

Re: Help with Motor Control Board

I guess I'll take it back apart and try to see if the relay will click with 18v battery (may not since is is a 24v relay)

Be careful when you make the connection to the relay coil because there is snubber diode connected in parallel with the relay coil so polarity of the connection must be observed.

[selldoor]

Re: Help with Motor Control Board

Hi here are a few links that has some info regarding this board the red black and white wires appear to be signal voltages for the speed?

http://www.fitnessrepairparts.com/cart/ViewItem/6005147

http://www.mc70repairexpert.com/default.html

The following one is for an upgrade board but I have included it as it suggests
the P1 potentiometer is to adjust the signal to the panel rather than the actual speed?
http://www.treadmilldoctor.com/troub...uctions-02.jpg

What model is your proform?

[keeney123]

Re: Help with Motor Control Board

Well the spec sheet of the IC is:
3.0 to 6.0V Supply Operating Range (page 1 of the spec sheet).
There must be 5V regulator some where on that board.
And also now you are getting 15V on 15V Zener now instead of 6.6V as before, what did you do?
Looking at this picture, top right is pin1.
https://www.badcaps.net/forum/attach...6&d=1420238187

I think the red wire connector goes to VDD pin 9 and the Black wire connector goes to Vss pin 10 of the ST62T60B6 chip. This can be verified by ohming it out.

[keeney123]

Re: Help with Motor Control Board

I'm wondering if P1 can be adjusted to balance out the +, - 5 volts. Perhaps it shifts the 0 Volt level?

[keeney123]

Re: Help with Motor Control Board

If you disconnect the red, black and white wire from the SCR board and measure the voltages on the wires again do they read 7 volts and 2 volts as you had read when they were connected?

[Crrose]

Re: Help with Motor Control Board

I guess I'll take it back apart and try to see if the relay will click with 18v battery (may not since is is a 24v relay)

[Crrose]

Re: Help with Motor Control Board

There are no schematics anywhere for this board other then the simple power diagram. How would I find out where a 5v regulator is.

Ok I tested the last two terminals on the top left of that picture. I don't know what I did wrong before but I am getting the correct voltage from the diodes now.

[budm]

Re: Help with Motor Control Board

Well the spec sheet of the IC is:
3.0 to 6.0V Supply Operating Range (page 1 of the spec sheet).
There must be 5V regulator some where on that board.
And also now you are getting 15V on 15V Zener now instead of 6.6V as before, what did you do?
Looking at this picture, top right is pin1.
https://www.badcaps.net/forum/attach...6&d=1420238187

[Crrose]

Re: Help with Motor Control Board

And I rechecked the diodes I replaced and I am getting 15.2v and 24.6

[Crrose]

Re: Help with Motor Control Board

I am looking for resistance not of the resistors, but the Voltages sure look kind of low.
BTW, you can also check the DC Voltage of the MCU ST62Txx between PIN 9 (Vdd) and pin 10 (Vss) to see if it has running Voltage (around 5VDC).

I get 8.3v on pins 9 and 10, if I checked the right pins, last 2 on the left side if looking down on it.