Horizon CT 7.0 Motor Control Board Johnson Fitness JDYF02L REVg

Thread Starter

Silmarillion

Joined Apr 26, 2015
14
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.
Awesome! Glad to hear it. I will post as soon as I get the MOSFETs and get the board repaired and tested.
 

Thread Starter

Silmarillion

Joined Apr 26, 2015
14
Yes I meant to say I could not find 220 ohm resistor that IamJatinah refereed to.
For me also 22 ohm resistor is fine.
-------
About Opto-Isolator:
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.
You can see U3 in the top picture above - on my board, it is a UC3842B - it is even labelled on the board. I come up with a description of a High Performance Current Mode Controller: http://www.onsemi.com/pub_link/Collateral/UC3842B-D.PDF. Is your board different than mine?
I think at this point, I will wait until I get the FETs, then see if it works from there.
 

Logical

Joined May 28, 2015
5
You can see U3 in the top picture above - on my board, it is a UC3842B - it is even labelled on the board. I come up with a description of a High Performance Current Mode Controller: http://www.onsemi.com/pub_link/Collateral/UC3842B-D.PDF. Is your board different than mine?
I think at this point, I will wait until I get the FETs, then see if it works from there.
Sorry my bad.
Above U3 is:
UC3842 Current-Mode PWM Controller DIP8
http://www.ti.com/lit/gpn/uc3842

Below U4 on the right side of the transformer is:
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
 

Thread Starter

Silmarillion

Joined Apr 26, 2015
14
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.
Sorry for the long wait for the conclusion to all of this - parts are cheap from overseas, but the MOSFETs didn't show up, and I had to get them re-shipped.
The good news is that the fix was the same as Logical's - replace the MOSFET and the kickback diode, and all is right with the board again.
The bad news is that the belt slipping problem that originally caused the issue is still there - I am now investigating possibly replacing the belt. Which I am pretty sure is out of the scope of this forum...:D
Thanks to all for your input on this! Hope this thread may save some others a lot of time and grief, particularly for this specific board.
 

Gelphine

Joined Feb 24, 2016
1
Great to know that you fixed the problem on this PCB assembly.
I do have the same exact unit that you have and my problem is there no Voltage going to the motor. The PCB assembly doesn't any visible burned components compared to your situation. Did you ever find the schematic diagram for this? I need everyone's help. Do you someone that sells the schematic diagram of this. Any comments and/or suggestions will be greatly appreciated. Thanks in advance...and have a nice day to all.
 

IamJatinah

Joined Oct 22, 2014
136
Hi All, my apologies for the absence. Ok, you have all done well, I must say I am proud, no horror stories, that's good!
There is a schematic in my head, I had it taped to the wall in front of my desk for about a year as we worked at correcting this unit from its rapid inception after a recall for previous Horizon treads which I remember happening in 2002 or 2004. But that's a whole different story.
This control board revolves around a pic16f687f if I remember, requires encoder feedback at your 5-pin connector from the rear of the drive motor, 177-teeth/slots per revolution, front roller feedback after 1.5sec, an active pwm drive from the upper board, and an active enable also from the upper.
The Light(LED) near the larger capacitors is an "energized" LED indicating the motor rail now has lethal power available, seriously :)
I may have mentioned a 220 ohm resistor by an output filter cap that may be a 22 ohm and is almost always covered(hidden) by white staking compound or glue. This resistor opens at times, is a chip resistor, careful replacing when needed. Sorry for that error.
Repairs for this board as you have read include the FET, kickback diode, check for console power at the 12-pin connector(long white connector) telling you the onboard power supply is working, this is usually about 15v at 3A(max) from the vertically mounted 3A diode near the small transformer. The lead coming from The top bend is the cathode, and has DC console power here referencing "DC GROUND" which can be found carefully at zener D4 anode or a nearby smt regulator.
DO NOT CROSS GROUNDS!
Crossing grounds, of which there are 3 on this board, a) Hot Ground - caution!, b) DC GROUND used by the console and all human interface points, and a totally separate power GROUND. Whew....be extremely careful!
I hear folks talking about 18v on the motor tabs....first, do not try to run any controller without a motor connected! The control board watches for a legal motor(inductive load) or it will sense an open and disallow any Red LED or motor rail power. The 18v people see on these tabs with or without a motor attached is a precharge voltage of 18vdc. This is not a source for the motor power, it is a biasing voltage to stabilize the super Hot motor rail for energizing.
If we didn't precharge this rail, we would weld relay contacts 50% of the time, and that just wouldn't work well, nor would we have a rational stable circuit at energize time which is a caustic in rush. Therefor, we precharged this rail.
Next, if your 3 storage capacitors are domed at the top, replace them, they are shot. Bulging tops are a sure sign of internal overheating and severe degradation, for a couple reasons I won't go into, just trust me, 3pcs of 560uf 200v caps.
The pic chip or uPc or cpu on this board requires the said feedbacks, pwm, enable, clock, power, and an internal programmed lookup table for speeds and regulations along with safety stops and a "dual relay" safety design for the motor rail.
You will see 4 relays. 2 up front for lift up and lift down. Then an L-shaped safety relay and a smaller relay right next to it.
When a user presses start....enable active to lower board, sanity check for powers and valid feedback for lift potentiometer. Next pwm begins, pic chip gets both and now engages small relay to precharge large capacitors for .2sec, energizes main safety relay, disables small precharge relay, checks all voltages, motor rail, motor sense, waits for feedbacks for 2sec, if valid full regulation and lift enabled upstairs and belt is turning.
For repairs look up fitness remedy in Sun Prairie wisc, there is no better fitness electronics repair depot in the US.
Good luck all....thanks for the kind words I've seen!
 

Thread Starter

Silmarillion

Joined Apr 26, 2015
14
Great to know that you fixed the problem on this PCB assembly.
I do have the same exact unit that you have and my problem is there no Voltage going to the motor. The PCB assembly doesn't any visible burned components compared to your situation. Did you ever find the schematic diagram for this? I need everyone's help. Do you someone that sells the schematic diagram of this. Any comments and/or suggestions will be greatly appreciated. Thanks in advance...and have a nice day to all.
Gelphine,
If you look at my original post, I didn't initially see any burned components, either. I did not find a schematic for this - I just went through and researched the most likely components to replace, and when I pulled and tested them, it was the common ones that were bad.
Thanks to IAmJatinah for all the awesome info!
 
I recognize this is an old thread but I just wanted to add my experience to the list. Special thanks to IamJatinah for the detailed information which was invaluable.

I decided to replace all five parts frequently mentioned in this thread (as each had signs of damage, with the caps all rounded, and the mosfet and rectifier blackened around the solder joints) and hoped to only having to take it apart once; the parts were relatively inexpensive.

I'm happy to report that after replacing those parts my treadmill is back up and running again! I'm not sure how long it will last since presumably this design is faulty but I'm glad to eek a little more life out of this old beast.

In case anyone is curious, the parts I replaced with (and the various Mouser part #'s) were:

661-EKXJ201ELL561MM5
MFG Part No:EKXJ201ELL561MM50S
EKXJ201ELL561MM50S
UCC Aluminum Electrolytic Capacitors - Leaded
US HTS:8532220020 ECCN:EAR99 COO:JP
Quantity: 3

942-IRFP260NPBF
MFG Part No:IRFP260NPBF
IRFP260NPBF
Infineon MOSFET
US HTS:8541290095 ECCN:EAR99 COO:CN
Quantity: 1

512-FFPF30UA60S
MFG Part No:FFPF30UA60S
FFPF30UA60S
Fairchild Rectifiers
US HTS:8541100080 ECCN:EAR99 COO:CN
Quantity: 1

Here is the fixed board after repairs:
IMAG0036.jpg

I also had to replace the "disconnect" style crimp-on connectors which connect to the motor as the plastic housing on the existing one was completely melted from when it failed.
IMAG0030.jpg
 

IamJatinah

Joined Oct 22, 2014
136
Great work!~ Your repair will cover you another 3-5yrs minimum, and this is a common part-set to replace anytime you have a "ripped" unit of this style. Have a super day and congratulations!
 

Taccess

Joined Nov 9, 2016
4
I realize this thread is a little old but it covers a very similar type of horizon MCB board .
My treadmill is a horizon Ti32 and my MCB board is JDYF07L REVi ( does anyone has a schematic ) .

I am asking if anyone can help me identify the blown parts on mine , I was walking on my treadmill when there were 1 really loud bang and it shorted the fuse /power in my house .

I opened the treadmill and took out the MCB , but cannot find a schematic for it anywhere , the replacement cost is out of my limit at the moment , so my only option is to find someone who can read there board and tell me the 3 parts in the pictures I have uploaded .

I am good with soldering but not very good with understanding how to read multimeters properly . If someone can tell me the three parts I can buy and solder them back on .

I appreciate any assistance .
 

Attachments

IamJatinah

Joined Oct 22, 2014
136
Hi There, well...this looks like the UK version of Horizons 2.5hp controller. The Capacitor that blew was a 68u 400v cap so we can assume there was a large spike or overvoltage situation to rip the on-board input filter cap, yes? I will edit thispost in a while when I have a chance to dig out the US version to help ID the burnt part which may be the incoming thermistor for the power supply. You will also want to check the FET mounted under the board, which is the main "switch" for this SMPS. This power supply usese the UC3842 maybe? No schematics available but I can help with some of that as I have drawn most of this board out but never put it into a SCH/PCB software library yet.......back shortly....
 

Taccess

Joined Nov 9, 2016
4
Hi There, well...this looks like the UK version of Horizons 2.5hp controller. The Capacitor that blew was a 68u 400v cap so we can assume there was a large spike or overvoltage situation to rip the on-board input filter cap, yes? I will edit thispost in a while when I have a chance to dig out the US version to help ID the burnt part which may be the incoming thermistor for the power supply. You will also want to check the FET mounted under the board, which is the main "switch" for this SMPS. This power supply usese the UC3842 maybe? No schematics available but I can help with some of that as I have drawn most of this board out but never put it into a SCH/PCB software library yet.......back shortly....
Hi Jatinah
Thanks for your help , yes to the spike ! I started up the treadmill and started walking very slowly and a couple of my steps stopped the treadmill belt for a sec and BANG was exactly what happened . So if I can fix this board I will lube the belt before using it .

That's great so 1x capacitor 68u 400v

Here is a 2 x photo of the back of my board
Including the fet .
I am new at this , so I am not sure which of the three pins on this fet is the gate the drain and the source ! However in continuity mode if I put the positive on the middle pin and negative on the left pin there is a constant beep and a reading of 2.7 . No other combination creates a beep .

If you can dig up those other 2 blown parts that would be amazing , and any advice with this fet to find out if it's good or not is also appreciated .

Regards
 

Attachments

IamJatinah

Joined Oct 22, 2014
136
Hi Jatinah
Thanks for your help , yes to the spike ! I started up the treadmill and started walking very slowly and a couple of my steps stopped the treadmill belt for a sec and BANG was exactly what happened . So if I can fix this board I will lube the belt before using it .

That's great so 1x capacitor 68u 400v

Here is a 2 x photo of the back of my board
Including the fet .
I am new at this , so I am not sure which of the three pins on this fet is the gate the drain and the source ! However in continuity mode if I put the positive on the middle pin and negative on the left pin there is a constant beep and a reading of 2.7 . No other combination creates a beep .

If you can dig up those other 2 blown parts that would be amazing , and any advice with this fet to find out if it's good or not is also appreciated .

Regards
 

IamJatinah

Joined Oct 22, 2014
136
Hi There...My apologies on not getting to that board just yet, but I haven't forgotten you and need to run by the shop late today yet. You sound like you do know a bit about what is going on there but a low reading that falls below a normal diode drop may mean that part is damaged. Not sure, but I will check this part with a meter here to help on your end.

I have a friend in the UK that knows these boards as well if you would like his info you can email me at jatinahATrocketmailDOTcom.Have a good day, back soon.
 

Taccess

Joined Nov 9, 2016
4
Hi Jatinah
That's great , i am hopefull that you can help when you do go to the shop .

I am new to this however I am willing to try and learn .

If anyone else has a working MCB control board JDYF07L REVI that can help , please see pictures in my first post above ,

Thanks
 

Taccess

Joined Nov 9, 2016
4
Hi Simarillion ,

Your board looks identical , if you are still around would you mind checking these other 2 parts I need to replace and let me kno the specs ? Pleaseee

Anyone ?..
 
HI Folks, your're correct......Good Luck! greg
I apologize if this is rather uncouth but I am desperate. IamJatinah, you appear to know a ton about these boards and maybe even helped design them! Would you be willing to please review my post here and give me your two cents on the damage I have done and possible remedies. Thanks in advance!
Josh
 

BAM5

Joined Sep 27, 2020
3
I just spent the day diagnosing this board and found an atypical issue.

Symptoms: Turns on, belt doesn't move.

Process: First I checked the mosfet. As IamJatinah stated, the relay coil clicks and the Red LED goes full brightness informing you the motor power rail is now under full (lethal!) power. After a failsafe timeout period with nothing coming back from the encoder the relay clicked off. I carefully (CAREFULLY) gave the mosfet 15V from a nearby cap (Soldered a stud onto the pin to clip an aligator lead to) to its gate and the motor gave a jerk as the capacitors quickly discharged through it. I highly do not recommend doing this unless you're very good. And please be aware of the Dunning–Kruger effect when thinking "Yeah, I am very good so I'll give it a go" You may think "What's the big deal, 15V is safe!" Well, it's floating 15V, meaning ground could be 95V and the positive "15V" could be 110V relative to you!

After that I checked the signal at the testpoint marked "PWM" with my oscilloscope that was hooked up via an isolation transformer for differential probing. No signal.

Followed the circuit back to what drives the pwm signal back to the opto that separates the high from low voltage. There's a white one (TLP521 [marked just p521]) that tells the mcu when the circuit is safe to give full power to the motor rail via the relay. Thanks to IamJatinah I realized this was to signal that the rail had the 18V precharge and was ready for full power. Shorting this will make the MCU believe the precharge is still being applied and will never turn the motor on, so this is another potential failure mode to consider if one of your symptoms is that the relay doesn't click on at all.

The black opto right next to it supplies the inverted PWM motor driving signal via pin 6 (the center pin that isn't cut off.) That had the (inverted) signal when probed.

Followed that trace to pin 6 of the first st lm339 chip and was an inverting input of one of the comparators. Pin 1 on that 14 pin chip now has the un-inverted PWM motor drive signal and when probed was present.

This makes its way over to the second lm339 to pin 7 (non inverting input) and the signal once again is outputted on pin 1 (on the second chip) However! Probing this yielded a very weak PWM signal that was only about 1V and the rails were at 0 and 15V so there was definitely something wrong with this part of the circuit.

Conclusion: It was a SOT23 PNP Transistor (marked BBH) labeled Q7 on the PCB; It had no physical sign of damage. It was shorting the pwm motor drive signal (from the LM339) to ground via the base pin to the collector pin (GND.) Probing the bjt for resistance from the base (probe+) to the collector[GND] (probe-) was netting about 100ohms whereas a fresh pnp salvaged off an old board was in the multi kOhm range. The function of this small bjt is to drive the large power mosfet for the motor, and as such it is located right next to the mosfet.

Just thought I'd add this failure mode to the tread since this is a top result when searching for this board model number on google.
 

jatinah

Joined Jul 26, 2010
17
I just spent the day diagnosing this board and found an atypical issue.

Symptoms: Turns on, belt doesn't move.

Process: First I checked the mosfet. As IamJatinah stated, the relay coil clicks and the Red LED goes full brightness informing you the motor power rail is now under full (lethal!) power. After a failsafe timeout period with nothing coming back from the encoder the relay clicked off. I carefully (CAREFULLY) gave the mosfet 15V from a nearby cap (Soldered a stud onto the pin to clip an aligator lead to) to its gate and the motor gave a jerk as the capacitors quickly discharged through it. I highly do not recommend doing this unless you're very good. And please be aware of the Dunning–Kruger effect when thinking "Yeah, I am very good so I'll give it a go" You may think "What's the big deal, 15V is safe!" Well, it's floating 15V, meaning ground could be 95V and the positive "15V" could be 110V relative to you!

After that I checked the signal at the testpoint marked "PWM" with my oscilloscope that was hooked up via an isolation transformer for differential probing. No signal.

Followed the circuit back to what drives the pwm signal back to the opto that separates the high from low voltage. There's a white one (TLP521 [marked just p521]) that tells the mcu when the circuit is safe to give full power to the motor rail via the relay. Thanks to IamJatinah I realized this was to signal that the rail had the 18V precharge and was ready for full power. Shorting this will make the MCU believe the precharge is still being applied and will never turn the motor on, so this is another potential failure mode to consider if one of your symptoms is that the relay doesn't click on at all.

The black opto right next to it supplies the inverted PWM motor driving signal via pin 6 (the center pin that isn't cut off.) That had the (inverted) signal when probed.

Followed that trace to pin 6 of the first st lm339 chip and was an inverting input of one of the comparators. Pin 1 on that 14 pin chip now has the un-inverted PWM motor drive signal and when probed was present.

This makes its way over to the second lm339 to pin 7 (non inverting input) and the signal once again is outputted on pin 1 (on the second chip) However! Probing this yielded a very weak PWM signal that was only about 1V and the rails were at 0 and 15V so there was definitely something wrong with this part of the circuit.

Conclusion: It was a SOT23 PNP Transistor (marked BBH) labeled Q7 on the PCB; It had no physical sign of damage. It was shorting the pwm motor drive signal (from the LM339) to ground via the base pin to the collector pin (GND.) Probing the bjt for resistance from the base (probe+) to the collector[GND] (probe-) was netting about 100ohms whereas a fresh pnp salvaged off an old board was in the multi kOhm range. The function of this small bjt is to drive the large power mosfet for the motor, and as such it is located right next to the mosfet.

Just thought I'd add this failure mode to the tread since this is a top result when searching for this board model number on google.
Nice work! Q6 and Q7 are set up as a push-pull across the +18v vcc to set up gate drive. About 25% of the time one finds a ripped IRFP260 you might expect this NPN / PNP set to be damaged ;o)
 
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