Bowflex nautilus firmware woes

[CuriousJohn]

I also measured d9. If I put red on the top foot (where there are two) and black in the middle, then I get 0.993

If I measure it the other way around, then the 1 stays (black on top and red in the middle)

This is showing the resistance is so high it cant read it so out of range on that range selected anyway, for a diode like this its ok if it reads low one way and high the other way so working fine. To read the higher resistance its possible to move the dial clockwise to select higher resistance range to test, looks like your meter goes up to 20 Mega Ohms!

So both R170 and D9 seem fine. This leaves possibility of damage or short due to excess solder around the supercap holes. It is weird fault tho as the servo pot gets it 5v supply from U19 on your board so not much to do with U17, perhaps U17 has become damaged?? (just thinking in type sorry)

With ref to "STJ":

super capacitors - also known by other names are a failed design.
they only survive a limited number of cycles and the cheaper ones in aluminium cans like to leak and wreck pcb traces.
the better ones from ELNA and NEC are steel-cased but still have a limited lifespan

if it's been replaced then check near it for damage from the old one - specially throughhole traces.
it's gets into the holes and eats the sleeve away

Take this seriously and inspect thoroughly.

The new photos of the underside with super cap removed, inspect it carefully the pcb has top and bottom layer so there are traces connecting to the top and bottom thru the holes via the sleeves and so all soldering has to be clean and neat both sides to prevent short circuits to surrounding area there can be no excess solder and i think you might have overdone it slightly. With supercap removed clean the solder up, get some solder braid to remove all excess solder around where you have been working it acts like wick to draw excess solder away when heated by the iron. Then use a magnifier to look closely and you can even shine a torch on the other side of the board to see all the traces that run around just to be sure there is no splash of solder shorted out anything and that the sleeves in the holes are ok and to test resistance of the sleeves should be near 0 Ohm do it by putting probes ether side of the holes that the supercap legs go into. All this said it is odd symptom to have so once cleaned up might be idea to leave the supercap out for now.

[CuriousJohn]

To go down a rabbit hole i might lean in to see inside lol....


So on the M8 if powered up when servo connected up console will not start and U17 gets hot but disconnect servo and it works lol, hmmm.... Let me take a second to think about this.

So on this M8 console looking at the photo, U17 is supplied 5v from BUK U16. U17 supplies 3.3v to the MCU U10 & U12 and various other sections but not the servo pot which has its own regulator providing 5v which is U19. So why weirdness at start up with hot U17 with servo connected?

Makes me wonder what is the resistance between the output of U17 and say the servo pot both at board pin outs is it J17? and actually when servo plugged in cos obv there is a pathway going on involving the servo so to find it. Which of U10 & U12 get hot if any when start with servo connected might have to try using IPA maybe try not to cook U17 to much tho ay.

[Zhinox]

Well, I first have to organize some solder braid. Then I can clean the soldering points. If I need to measure anything else, I can try that.

Regarding d9. I measured up to 20 megaohms. It always came out as 1🤷

[CuriousJohn]

Good plan!

The display with the 1 in the left most digit is normal.

It indicates that the connected resistance is too high to measure on the selected scale

[CuriousJohn]

I also measured d9. If I put red on the top foot (where there are two) and black in the middle, then I get 0.993

If I measure it the other way around, then the 1 stays (black on top and red in the middle)

I think 993 ohms just under 1K is a decent reading for a diode in the forward direction. The other way its high, suppose thats ok to its a diode!

[Zhinox]

I have now cleaned everything with a soldering braid. However, the same problem still exists.

[CuriousJohn]

Weird fault, console will not power up with servo connected and U17 gets hot?

It sounds like something supplied by U17 is shorting out stressing this regulator but given the servo pot and motor have there own voltage regulators it could be tricky to find unless its somethng simple like a wiring harness issue.

There are three elements to look at to isolate the problem so each must be ruled out i think its best to cover the straight forward things first.

1. Servo (pot & motor)
2. Harness cables between console board and servo (2 of them)
3. Console board (tricky)


REF: M8 Console part labels:

J17 main 9 pin connector

U10 LED driver Holtek HT1632C
U12 MCU NXP LPC54605J512BD100
U16 BUK 5v
U17 3.3v reg L1RC
U18 WT7901 - Motor driver
U19 5v reg for servo pot



1. Check servo

Be sure the servo works exactly as it should when connected up after powering the console on, if you had a second servo unit to rest that would be perfect so assuming you dont you have got to test the one you have thoroughly:

Power up console with servo disconnected, now connect servo and select manual program and confirm if resistance can be changed across the range from 1 to 20, not just on the screen but does the brake move when you increase and decrease resistance. Keep eye on the brake if something is wrong it will move to far or not at all, also see the service manual page 33 "calibration of brake" for better understanding on its operation, Link below:

Bowlfex Max M7 service manual
https://www.manualslib.com/manual/15...rainer-M7.html

INFO

The servo contains 1x 5K pot that you have already measured and a DC motor, take a look at the diagram for the M7 from post 58, on the left is drawn J15 the 9 pin male connector on the console board, on the M8 it is labelled as J17, I believe this is laid out the same on your console for e.g. pin 9 is ground and pin 8 is 9v DC input.

Pin 1 & 2 drive the motor, the traces from them should go to U18 "WT7901 - Motor driver".
Pin 3 gets 5V dc from U19 and this goes through the pot and back to the board at pin 4 where it likely goes to the MCU U12 where the voltage is measured so it knows where the brake position is.
Pin 5 goes to the pot (well from it really) and to ground via FB10?


Interesting test:

The console should go to sleep after 5 minutes of no use, pressing any button or turning the crank will wake it up. Does yours wake up and is it usuable if you power it on with servo disconnected then connect the servo and wait for 5 mins. Does it go to sleep, does it wake up? it will measure the servo position i think so interesting to see how it behaves.


2. Check harness

If servo works 100% then:

Read page 11 of service manual, follow the flow chart.

Got to check the harness connectors and wires are not damaged, maybe a pin get bent or the wire got nicked and is shorting out sending to much power to the MCU U12 or even grounding it when servo connected for e.g. this would cause such a fault but does not explain correct operation if servo plugged in after power up and working fully.

There are two wiring harnesses, first is a short cable harness between console board and the neck of the machine that runs through the upper console assembly, where it plugs into the 2nd longer harness cable that goes down through the machine and comes out the bottom where you plug in the servo. I would suggest checking both cable harnesses separate first, inspect all connectors for visible damage and measure the resistance of each wire between its connectors on both ends also check against every other wire looking for shorts (0 Ohms resistance or close to) A copper wire should have very low resistance so look for low resistance between pins. Take a methodical approach so on top connector keep red probe on pin 1 and measure all other wires that come out other end bottom connector. Obv only the corresponding pins should show continuity (low resistance), for e.g. if any other pin than pin 1 on the bottom shows low resistance to pin 1 on the top then there is a short circuit in the wiring harness.

When finished testing them separate and find no issue connect them both togethor and test again like its one single harness it might show up some problem in the middle connecting section.


3. Console board nightmare section.

This section could be challenging with just a basic multi meter and little experience..

First thing to do is power up the board with servo disconnected and see if 5v dc is coming out of U19, measure at the bottom plug where the servo plugs in you may have to trace the wires a bit to fathom out but you already know where the wires in the servo plug go so not hard consult the diagram of M7 measure between ground and the 5v pin connected to U19. If reading is more than 5v maybe could cause your fault condition and given the U12 MCU could stress if more than 5v reaches any of its pins but again surely would happen when servo plugged in after switch on.

FIND THE FAULT ON THE BOARD.

U17 gets hot it supplies 3.3v to MCU and other components especailly logic stuff, it means something it feeds is sick. Maybe U17 itself has become sick due to long term overheating thanks to supercap surges?

Is U12 MCUgetting hot as well as U17? Unless you have a thermal imaging device use IPA technique to find what component is causing U17 to stress, IPA will evaporate off warm components quicker and is easy to see
If you find it then chances are gunna need hot air station and fine solder technique as much on these boards is surface mounted and easy to maul.

I will stop now until you exhaust 1 & 2 and there is no guarantee of success for you from this point forward sorry. I would wonder if U17 has been damaged due to long term stressing so might try replacing it to see but again hot air needed or fine solder iron skills. Also does the BUK U16 get hot along with U17 because U16 feeds U17 same as on M7 just labelled different.

Also using jewelers loope or similar inspect every component especially the big chips looking to make sure no spec of anything solid or liquid is between pins and clean it up thoroughly with IPA all over, i restored a console doing this not long ago so easy for a spec of something to disrupt the delicate and complex processes going on in this kit it needs to have all its voltages at correct levels on startup to boot and it checks!! It logs fault codes mentioned in the service manual of the M7 they can be viewed goign into the setup screen (is M8 the same?) but as of yet the fault codes remain unknown.

[Zhinox]

I found someone on reddit who had the same problem. He replaced the servo and the wiring harness. Neither of them helped. Maybe I'm missing something

https://www.reddit.com/r/Bowflex/s/fVWSTUd9Yu

the last pictures on reddit of the console are mine

[CuriousJohn]

I found someone on reddit who had the same problem. He replaced the servo and the wiring harness. Neither of them helped. Maybe I'm missing something

https://www.reddit.com/r/Bowflex/s/fVWSTUd9Yu

the last pictures on reddit of the console are mine

My last post was extensive, not sure I can help further.... Something is surging at start with servo connected might not even be in the pot or motor but connected to its driver circuits including main MCU U12 or its voltage regulator U17 L1RC.

You might see if the fault is related to the pot or servo motor side of things by only connecting the 3 pot wires in the bottom connector and try powering on, it will mean using some wire like dupont wire pictured below to jury rig a connection to the 3 pot pins leaving the motor disconnected. Be advised just connecting the servo motor without pot could cause the motor to drive continuously breaking something so if your going to try do that best do it with bowden cable disconnected at the least.

[CuriousJohn]

If you fancy a "stranded on dessert island solution" quick and cheap fix as suggested in the redit thread you could get a 3 pole switch and wire it in to the servo harness wires somewhere and maybe run some short wires to have the switch where its convenient to get at when power on, maybe theres some with 5 pole switches with illumination on that would swish haha. "Isolate servo before connecting 9v DC".

Probs use a 3 pole single throw switch with 1 pole switching 1 of the servo motor wires and the other two ploes on the pot. Testing will tell ya but watch out you dont run the servo motor as it could keep running all the time wrecking something without having the pot connected properly so keep one wire on the motor disconnected when testing how many disconnected servo wires it takes for the console to start.

[Zhinox]

So, it just took a while. I've now organized some cables and tested the servo. I've now discovered that if I connect everything except the middle cable on the potentiometer, everything works. As soon as the middle cable is connected to the middle of the potentiometer, the console doesn't turn on. However, if I briefly lift the cable in the middle, the console turns on again. I also made a direct connection to the potentiometer to rule out a broken cable. I hope I was able to explain it somewhat.

[Zhinox]

When I measured the potentiometer individually, everything worked. What could be the problem if the middle connector has contact from the beginning, preventing the console from starting?

[CuriousJohn]

Congrats on isolating the fault more closely its not easy to do but thats major progress! I can think of three possible scenarios to check for but there might be more.

First some theory of operation:

Post 54 shows the Updated power Distribution of M7 console., with reference to it:

5v DC is provided by U19 on the diagram of the M7, on your M8 that part is labelled U20. so M8 U20 sends 5v to pin 3 of J17 (J15 on diagram as M7 label) which then goes down the wire to the left side pot pin (or the right depends how its wired doesnt matter), the pot acts as a potential divider and send some of the voltage back down the middle pin up the wire to pin 4 of J15 where it travels along the traces through one or two surface mount components to be measured by pin 6 of the PIC32 MCU which on your M8 console is U12.

U12 measures the voltage received from the pot and compares it to what is stored in its memory adjusting the motor till that value corresponds to the resistance level set by the user.

My first thoughts on your fault is three sided, first understand the PIC32 MCU is a 3.3v device that has some pins that are 5v tolerant ( as described in its data sheet you can download if wanted), if the MCU receives more than 5v on any pin it may cause erratic behavior and even failure so first check U20 is working right. U20 needs to be precise stable 5v output its highly regulated as its voltage is measured by the MCU as described above so needs to be stable for that purpose.

3 steps....

1. First job is check the voltage of pin 3 of J17 with reference to ground (pin 9), it should be 5v DC. If its much higher than 5v then thats likely the issue.

2. Assuming 5v dc is present on pin 3 then with a magnifying glass unless you have great vision inspect the trace from pin 4 of J15 and follow it all the way to the PIC32 MCU, on the M7 it goes to pin 6 of U14 on your M8 its labelled U12 and may be different pin hard to tell by photos. The trace may disappear through a hole onto the other side of the board and then re emerge they can be tricky to follow and a torch on the other side of the board can help to see it also use continuity test on your meter. The diagram shows at least one smd capacitor coupling that trace to ground to smooth any noise in the signal, if this capacitor is short circuit it could surge the power at startup causing your fault, if open circuit i.e failed then erratic behaviour might be the result so a way to measure the capacitance value of it in circuit would be useful.

A good test would be with pot disconnected and board powered down so nothing plugged into J17, measure the resistance between pin 4 of J17 and pin 9 (ground) where pin 4 goes to the middle pin of the pot as we believe. The resistance between pin 4 and ground should be high in the Mega Ohms range so start with your ohm meter dial on low ohms range and test each range going up till you find the resistance. if there is a short to ground here you should see low ohms maybe even dead short. However the fact the servo works ok if plugged in after power up suggests this fault is unlikely or the SMD capacitor is low value or failing but still about functional. Also worth checking resistance of pin 5 of J17 to ground, it should be direct to ground as this is the grounding point for the potential divider so 1 Ohm or less would be expected here.

3. If 1 & 2 check out then its ether an internal fault with U12 or some wild thing going on with the servo pot itself so replace the pot or borrow another servo to test with as its easier than replacing U12 which will also need programming in that scenario and no guarantee of success. You could probably extract the firmware if you got a PIC kit 3 and downloaded the IPE software but thats way advanced stuff for now much easier to rig a switch to isolate the middle pin of the pot at startup, if i where doing that i would also isolate at least one of the motor wires on pin 1 or 2 just to prevent the servo operating full on if the PIC32 MCU cant read a voltage signal from it at startup as that would likely wreck the servo pot and mash the gears. A single throw double pole switch would do that job nicely for a cheap and dirty fix anyway.

[CuriousJohn]

Just took delivery of a working M8 console bagged for cheap lol and can confirm the J17 pin out is identical to the J15 of the M7 console and they would swap over direct apparently the M7U is an upgraded M7, its basically an M8 console on M7 machine so direct compatibility.


J17/15 resistance to ground (pin 9 brown) measured at the cable in the neck so no servo connected and no power but measurements should be similar if taken direct from the J17 pinouts on the console.

Pin
1 - 1.9KΩ (rising up)
2 - 5.4MΩ
3 - 1.33KΩ <-------- Reads 5.12v dc with ref to ground when powered up with no servo connected.
4 - 3.45MΩ
5 - 0.8Ω (short to ground as it should be the 0.8 is my meters leads)

[CuriousJohn]

I found some interesting info on the M8 console:

The "M7u" is simply the M7 model that now has a stock M8 console, so it can be treated as an M8 from now on.

Unfortunately, your constant "LOADING" issue MIGHT ultimately require a new M8 console (or you could re-install the machine's original M7 console if you still have it).

Some background info:

The M6/M8 Max Trainers have the capability to have their console firmware to be updated (to fix bugs or add features etc.) via an over-the-air ("OTA") process or via the USB port located on the back of the M6/M8 consoles. The OTA process is done via the JRNY app that is loaded on the owner's phone/tablet. The phone/tablet connects to the M6/M8 console via Bluetooth, and the phone/tablet will use WiFi to connect to the internet to the Bowflex JRNY servers to transfer the new firmware.

When an M6/M8 console needs new firmware, the screen will show "UPDATE REQUIRED" (which can occur when connected to the Bowflex JRNY servers, or after a certain amount of usage hours), then the typical process to update the firmware would be via following the prompts on the JRNY app.

Unfortunately, sometimes the firmware update process, the screen will continuously show "LOADING" and basically "brick" the console.

OK, I just wanted to explain that firmware loading process as it MIGHT come into play to eventually try and fix your issue...but first let's proceed down another path.

Replacing your servo motor is not the cause of your issue...just an unfortunate coincidence likely triggered by the power-cycling of your M8 console.


***Try the following to see if it will correct or perhaps change your issue's behavior. Report back with your progress or questions.

Note the first part of this at Step 2 might take 2 people.

Unplug the M6/M8 from either the wall or the machine.

(Here is the 2 people part) While pressing the "Programs" button on the M6/M8, plug in the machine.

Keep pressing the "Programs" button, and then after the M6/M8 fully powers up, release the "Programs" button.

The M6/M8 should then go through the factory restore process. During this time, the M6/M8 will display in order: Updating Flash, Loading, Updating BLE & Power Cycle.

When "Power Cycle" is displayed, unplug the M6/M8 from either the wall or machine and plug it back in.

When the M6/M8 powers back up it will display in order: Starting, Loading, Max Trainer & maybe Update Required.

If "Update Required" is displayed, then connect to the M6/M8 with the JRNY app that is loaded onto your phone/tablet.

Use the instructions in the app and on the M6/M8 display to install the latest firmware (note more than 1 power cycle may be required) during the firmware update process.

[CuriousJohn]

My bad the M8 MCU U12 is not a PIC32 but a 100 pin "NXP LPC54605J512BD100".

Pin 4 of J17 goes to Pin 79 of U12 via a 100Ω resistor labeled R157 with C107 coupling it to ground which is the coupling capacitor I was referring to earlier so one side of C107 should be ground, if both sides are ground then its short circuit of that capacitor, not easy to test O/C with it on the board. I tried measuring C107 in circuit but its tiny something like 1nf.






For the lols

[CuriousJohn]

Just replaced another failed super cap on a Max M7i console and it looked ok on the outside but when cut to make removal simpler the evidence showed itself, see photo below.

The console was starting up ok but on power up had garbled screen breifly which corrected itself in a second or less then goes straight into the setup routine every time, upon testing the supercap it was found to hold 100mv only with power removed and would come up to 4.3v instantly so knew it was dead before snipping. All sorted after replacing the super cap.

[CapLeaker]

Typical small supercap behaviour.

[CuriousJohn]

Hey CapLeaker.

Have done a handful of these now but this is by far the worst condition one I found yet, reckon its about 6 year old no more. What a scandal