# Horizon CT 7.0 Motor Control Board Johnson Fitness JDYF02L REVg

#### Silmarillion

Joined Apr 26, 2015
14
Hi there,
I am looking for some assistance troubleshooting this board (or at least determining if it's out of my league :>). I have found a number of similar motor control board issues on here, but nothing specific to this particular one. Other possible relevant info from the board: 2.25-2.5 JC07-001 SJED08089IF Ver H109S106

Description of the issue: The treadmill had stopped and requested a belt lube (we have done this before, but it has never actually come up with the maintenance message). Lubricated the belt & did a thorough cleaning, reset the maintenance message, put it all back together & worked OK. I had started using it again, and noticed that the belt was slipping when I got it slowed down to a walk speed (wasn't happening (at least noticeably) at higher speeds). I was going to finish my workout and try adjusting the belt tension, when it made a popping noise (combined with a glitch on the TV), the belt motor stopped, and I could smell the magic smoke :>)

Troubleshooting done so far: I used some of the very helpful information on the Treadmill Doctor site to narrow down the issue. I tested the motor with a battery - still works. The control panel, elevation motor, etc. still work, and Treadmill Doctor indicates the issue is the motor control board. The red LED on the board does not light when everything is connected. I have removed the board from the aluminum mounting plate / heatsink, did a visual and "sniff test", but I don't see anything blatantly obvious (burned components, bubbled caps, etc.). I did a bit of poking around and *may* have found one bad diode, but apparently had a brain fart and forgot to document it...

My skill set: I have decent soldering skills & tools, and basic electrical / electronic knowledge. Although I did electronics as a hobby when I was younger, and went to school for electronics, that was in the 80's, and my jobs have been in IT. I could do some basic component testing / replacement with some help / direction. I would just replace the board, except for the cost (I was recently laid off, and am trying to conserve funds), and the concern that a replacement board may wind up in smoke as well, particularly if I am still having issues with the belt. The treadmill is a few years old, and I am not sure if the board is worth the cost to replace for the value of a used treadmill.

So whatever guidance anyone can supply would be greatly appreciated. Concern with repair is the amount of time and effort involved to make sure I get everything if there are multiple components damaged, with getting components, and with sinking a bunch of time and money into a project that is over my head, or possibly not fixable (at least by me :>).
I don't take offense easily, so please feel free to be candid with comments (but hopefully avoiding outright insulting :>). This looks like a great community with some very helpful members - thanks in advance, even if just for the information I have already found on here. I have added a couple of photos as per what I have seen in the other threads.

Thanks!

Joined Jul 18, 2013
26,277
As the red LED is labeled DC and is close to the bridge rectifier, I would start by measuring the output of the bridge rectifier and reverse engineer what part of the circuit the LED is monitoring. This may offer a clue.
BTW, the Johnson motors are made well in spite of being Chinese origin!
Max.

#### Silmarillion

Joined Apr 26, 2015
14
Thanks, Max. I haven't really tried to do any live troubleshooting on it - thought I would start by looking for anything obvious and doing a few basic checks. Do you think it's OK to run the board for a minute or so for testing without remounting everything onto the heatsink plate?
Also, are there schematics for this type of board available? I don't even know what a lot of the components are, let alone try to "reverse engineer" it

#### #12

Joined Nov 30, 2010
18,224
Top board R18

Joined Jul 18, 2013
26,277
If you don't run the motor it should be OK to hook power to the board for testing, that board is not among the ones I have schematics for, in many cases schematics exist on the web due to some one taking time to reverse engineer the board.
Max.

#### Silmarillion

Joined Apr 26, 2015
14
Top board R18
Thanks, #12, but R18 is fine - just the picture that makes it look bad. Had to go look at it again just to check :>)
Thanks, Max - I will check the bridge rectifier output. Seems OK on a passive check (first thing I checked besides visual & sniff test).

#12

#### Silmarillion

Joined Apr 26, 2015
14
OK - so I hooked it up and checked a few things, but I didn't get very far. You can see in the photo that the AC1 terminal goes directly to one input terminal of the bridge rectifier. AC2 goes to the contacts on the relay labelled JQX-105F-1. It's difficult to test the board live because of the limited length of the cables and the risk of shorting something, but I was able to verify that there is not 12V present at the coil terminals of the relay, even when the treadmill is on and the motor would be expected to be running.
As I mentioned in my original post, the elevation motor still works, along with the control panel, etc., so I would assume (given what happened - how it blew up) that the issue is probably in the portion of the circuit that provides power to the belt motor (not to be bleeding obvious or anything, but as opposed to, for example, the board not having power at all). Although that doesn't explain why there is no voltage to the coil...

I was hoping that someone else here had previous experience with this particular board, as that seems to be the case with some of the other Johnson Control boards.

Joined Jul 18, 2013
26,277
On some T.M. boards the LED is the 12vdc indicator, generally produced from a zener diode and resistor/capacitor circuit, this my be one avenue to look for as I would expect the DC LED to be lit.
Max.

#### Silmarillion

Joined Apr 26, 2015
14
On some T.M. boards the LED is the 12vdc indicator, generally produced from a zener diode and resistor/capacitor circuit, this my be one avenue to look for as I would expect the DC LED to be lit.
Max.
Yeah, don't know what "normal" status is on the "DC" LED, or if it indicates 12V or variable DC to the motor. Was hoping someone else had seen this particular board and might be able to chip in. Dug through some more threads that have other boards from Horizon treadmills - they are quite different from this one, but at least gives me some ideas of what to test. Just haven't had much time to look lately - will reply once I get another poke at it, if I don't get anything else on this thread.

#### Silmarillion

Joined Apr 26, 2015
14
OK, after some more forum-surfing and going back to a couple of similar posts (for different boards):
I am guessing the most obvious parts to check are D4 (kickback diode, in T220 case, top centre in the picture above), and Q4 (just to the right of the diode).

D4 is a Fairchild Semiconductor F30U60S 30A 600V fast recovery diode. It reads .107 both directions on the diode check setting on my meter (out of circuit). Seems odd to me - I would have expected short or open if it's bad, or a higher reading (maybe .5) if it is good, based on specs: http://www.mouser.com/ds/2/149/ffpf30u60s-298177.pdf. Any comment from anyone more experienced / knowledgeable than me?

Q4 (IRFP260N Power MOSFET) is shorted between all pins. I also checked the other larger diodes, but didn't find any other issues. Any suggestions for other components I should check, before I replace these and give it a try?

Any suggestions for Canadian sources for these components? I am in Calgary, AB, so I may try a local supplier, if the prices are not outrageous (probably MRO http://www.mroelectronics.com/mro/). Otherwise, I guess it's ebay (parts are $2-3 ea.). #### MaxHeadRoom Joined Jul 18, 2013 26,277 .107 in both direction indicates a shorted diode. I am also in Canada, I get Digikey shipments FedEx next day air for CAN$8.00, no brokerage etc.
I would be very surprised if they do not have a close sub or exact item.
Max.

#### Silmarillion

Joined Apr 26, 2015
14
.107 in both direction indicates a shorted diode.
I am also in Canada, I get Digikey shipments FedEx next day air for CAN\$8.00, no brokerage etc.
I would be very surprised if they do not have a close sub or exact item.
Max.
Thanks, Max! Will post back once I get a chance to try replacing these.

#### IamJatinah

Joined Oct 22, 2014
136
HI Folks, your're correct, the FET and kickback diode have died. Please also check the 22ohm resistor leading to the FET gate as it can be taken out during a FET short, and also there are a "push-pull" set of transistors, maybe labelled Q6-Q7, small SMT transistors next to the FET should be checked as well.
Testing can ONLY be done in the treadmill unless you supply 2 feedback signals to the UUT(board) during testing to satisfy the PIC chip, controller CPU. Lastly, during FET shorts, there is also a tiny 220ohm resistor that can open near an output filter cap leading to an opto-isolator which is the drive line for the PWM speed signal.
Let us know how the repair goes, parts are available at Mouser or Digikey for these repairs. Good Luck! greg

#### Silmarillion

Joined Apr 26, 2015
14
Thanks, Greg! Appreciate the heads up on the other parts - I will check these. I have ordered parts from overseas, so I am waiting for them to arrive (currently unemployed, so trying to pinch pennies :>).
Can all these parts (especially the SMT ones) be checked in-circuit? Don't have SMT tools - I have done SMT parts replacements with regular soldering kit, but that was many years ago, and using commercial equipment (I just have basic home soldering tools & supplies).

#### Logical

Joined May 28, 2015
10
Thanks, Greg! Appreciate the heads up on the other parts - I will check these. I have ordered parts from overseas, so I am waiting for them to arrive (currently unemployed, so trying to pinch pennies :>).
Can all these parts (especially the SMT ones) be checked in-circuit? Don't have SMT tools - I have done SMT parts replacements with regular soldering kit, but that was many years ago, and using commercial equipment (I just have basic home soldering tools & supplies).
Hi Silmarillion, I am new to this site. Thanks for the detailed description of your problem and clear pictures of the board above.
I have same control board as yours and have same problem as yours. For me kick back diode F30U60ST was burnt which I replaced
MOSFET IRFP260N is shorted. I have ordered it and will get in a day or so. Then I will replace it as well.
Did you find any more components/parts damaged?
Did you make any further progress?
I could not find 200 Ohm Resistor refered to by IamJatinah above. Could you or IamJatinah let me know of it's exact location?
Did you draw any circuit diagram or know where I can find one for our board or of any board close to ours?

Thanks and Regards

#### Silmarillion

Joined Apr 26, 2015
14
Hi Logical,
No worries - I am new to the site as well, and don't have a lot of current skill / expertise in troubleshooting discrete electronics.
I haven't had a chance to look at the board again and verify if there are any other components damaged - my current project is doing troubleshooting on my car (somewhat higher priority :>). I will post back when I get a chance to look at it.
I never found any sort of circuit diagram for the board - if you do find one, please post here so others can find it, as I haven't seen any other posts referring to this specific board.
Thanks!

#### Silmarillion

Joined Apr 26, 2015
14
Got the diodes, just waiting for the FETs.

IamJatinah - thanks again for the additional info. The 22 ohm resistor is fine. I believe Q6 and Q7 are OK - will see if the board works when I get the FET and diode replaced. I couldn't find the 220 ohm resistor you mentioned, and I am not sure which IC is the optoisolator. Most of the ICs have the part numbers blacked out, and the of the few I was able to make out, none were an optoisolator. There is also goop (rubbery caulking-type stuff) over a lot of the small parts - I can scrape it back if I know where to look, but haven't figured that out yet :>) I can post another picture if you are able to tell me where the general location is.

Logical - were you referring to this same resistor? Was unsure, as you wrote "200 ohm resistor".

New look of the site is great! Much cleaner and more "modern looking" :>)

Joined Jul 18, 2013
26,277
Opto's are generally 6 pin or 4 pin IC's, I can see a couple of 4 pin types by U5.

On the site, as of now 78% have opted to change back to the old format possible in the personal set up page.
Max.

#### Logical

Joined May 28, 2015
10
Got the diodes, just waiting for the FETs.

IamJatinah - thanks again for the additional info. The 22 ohm resistor is fine. I believe Q6 and Q7 are OK - will see if the board works when I get the FET and diode replaced. I couldn't find the 220 ohm resistor you mentioned, and I am not sure which IC is the optoisolator. Most of the ICs have the part numbers blacked out, and the of the few I was able to make out, none were an optoisolator. There is also goop (rubbery caulking-type stuff) over a lot of the small parts - I can scrape it back if I know where to look, but haven't figured that out yet :>) I can post another picture if you are able to tell me where the general location is.

Logical - were you referring to this same resistor? Was unsure, as you wrote "200 ohm resistor".

New look of the site is great! Much cleaner and more "modern looking" :>)
Yes I meant to say I could not find 220 ohm resistor that IamJatinah refereed to.
For me also 22 ohm resistor is fine.
-------
Location: It is an IC in the middle of the board, above the label U3.
Description:
6n138 DIP-8 High Speed OPIC Photocoupler
LOW INPUT CURRENT HIGH GAIN SPLIT DARLINGTON OPTOCOUPLERS
http://www.vishay.com/docs/83605/6n138.pdf
High Speed Optocoupler, 100 kBd, Low Input Current,
Photodiode Darlington Output
-------
I received my MOSFET (IRFP260N) from US seller couple of days back and I will replace it soon.

#### Logical

Joined May 28, 2015
10
Yes I meant to say I could not find 220 ohm resistor that IamJatinah refereed to.
For me also 22 ohm resistor is fine.
-------
Location: It is an IC in the middle of the board, above the label U3.
Description:
6n138 DIP-8 High Speed OPIC Photocoupler
LOW INPUT CURRENT HIGH GAIN SPLIT DARLINGTON OPTOCOUPLERS
http://www.vishay.com/docs/83605/6n138.pdf
High Speed Optocoupler, 100 kBd, Low Input Current,
Photodiode Darlington Output
-------
I received my MOSFET (IRFP260N) from US seller couple of days back and I will replace it soon.
Hi Silmarillion,

GOOD NEWS!
I replaced the MOSFET (IRFP260N) in the board now and my treadmill is up and running now
Note: I did also replace the kick back diode F30U60ST, which was burnt, earlier. So total two parts replaced.