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
CuriousJohn
Ordained
Last Activity: 03-29-2025, 06:44 AM
Joined: 12-25-2018
Location: Britain
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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.
[ATTACH=JSON]{"data-alig...Leave a comment:
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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.
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"m8-power-issue-v0-4ool3mkohuje1edit2.webp","data-attachmentid":3592491}[/ATTACH]...Last edited by CuriousJohn; 03-13-2025, 02:35 PM.Leave a comment:
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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...Leave a comment:
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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...Last edited by CuriousJohn; 03-13-2025, 08:10 AM.Leave a comment:
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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 [B]Updated power Distribution of M7 console.[/B], 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...Last edited by CuriousJohn; 03-13-2025, 06:13 AM.Leave a comment:
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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...Last edited by CuriousJohn; 02-22-2025, 01:38 PM.Leave a comment:
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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...Last edited by CuriousJohn; 02-22-2025, 12:09 PM.Leave a comment:
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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....Last edited by CuriousJohn; 02-22-2025, 09:38 AM.Leave a comment:
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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!...Leave a comment:
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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
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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...Last edited by CuriousJohn; 02-19-2025, 03:17 PM.Leave a comment:
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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,...Last edited by CuriousJohn; 02-19-2025, 03:01 PM.Leave a comment:
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thanks for the photos appreciated.
The servo measures ok then, good to confirm.
The Supercap is holding its charge of 4.3v when no power to the board, its ok by sounds of it. The supercap is supplied with 5v through D9 and R170 should measure 100 Ohms if you measure the resistance of it with your meter when power is off, nice little calculator for working out SMD resistors to numbers on top = the value in ohms it should be: [URL]https://www.hobby-hour.com/electronics/smdcalc.php[/URL].
As for the diode that SOT23 package contains only 1 diode as drawn in...Last edited by CuriousJohn; 02-19-2025, 12:34 PM.Leave a comment:
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these boards where my first real dealing with super caps so thanks for this.
For the record I bought replacements of ebay, they are named "Powerstor" so far seem ok : [B]0.33F 5.5V Coin Cell Supercapacitor KR-5R5V334-R Memory Backup Multi[/B]
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3575683}[/ATTACH]these boards where my first real dealing with super caps so thanks for this.
For the record I bought replacements of ebay, they...Leave a comment:
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The Servo seems ok then, thats good news you didnt mention it going out of resistance setting when set so assumes it doesnt. It would be an idea to check the resistance from the middle pin to each outer pin they should both be different readings unless you managed to put the pot dead centre lol but both readings will add up to the total you measured of 5.18K or thereabouts, just to confirm the pot is fully working as it should for completeness if you care to lol.
Did you say the supercap you put in does not hold 4.3v after powering off but drops rapidly after removing power? if so...Last edited by CuriousJohn; 02-19-2025, 09:06 AM.Leave a comment:
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Hi Zhinox. The M8 console may be slightly different to the M7 internally, i know M8 can use the JRNY app so has different technical abilitys to the M7 I would be very interested to see a decent quality photo of the inside of it if you have the back off still.
As for your fault you say L1RC gets hot, is that labelled as U18?
This fault does sound a bit funky which leads me to wonder if the supercap is failing, after a day or two maybe a week being powered off, does it ask for the date and want to setup a user profile like its the first switch on? If its behaving like that...Last edited by CuriousJohn; 02-18-2025, 07:37 AM.Leave a comment:
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ooow that cooked, Gods house is below it the "I AM" 🤣, once repaired do not watch porn on it again or God will nuke it a second time from his house.
As you where fixing stuff and been all productive...Leave a comment:
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Its a resurrection!
Our Triton T100E thermostatic shower (About 14 years old now apparently going by its date labels) has been playing up since we moved in a year ago, same as described in op at start it would low pressure fault but if quick you could press cold button and then warm button and it would run luke warm, ok in warmer months but this winter it started refusing to switch the heater element on both economy and full power very much like the Burco boiler that had the same problem. Upon investigation a polypropylene X2 capacitor was found failing, should have been 0.68uf but...Last edited by CuriousJohn; 01-16-2025, 10:57 AM.Leave a comment:
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Burco 5L boiler autofill boiler firmware fun
After repairing the faulty control board of this Burco BCPLSAFWM5L 5 Litre Wall Mounted Automatic Water Boiler With Filtration it was time to see if the firmware was unlocked for backup and learning STM8 stuff.
Video 1 - connecting saving firmware hex files.
[url]https://youtube.com/shorts/lB_quEeCop4[/url]
video 2 - Writing saved Hex files back.
[url]https://youtube.com/shorts/_r7AXijnhyY[/url]
Video 3 - Erase and restore MCU
[url]https://youtube.com/shorts/NQV_1N2GkF4[/url]
...Leave a comment:
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