Received the replacement mainboard for my Snapmaker J1(s) yesterday Feb 22, 2023. Immediately began replacement.
Some issues with new board were noted.
(1) New heat sink bonding material for underside of board was not included, I was able to carefully peal off rubbery material from original board with flat blade scraper, maintaining shape and thickness of both pieces, and apply to replacement board.
New compound should have been supplied as original was quite well stuck to board and may have acquired some conductive material from original solder pads. (I see some “blooming” white coloration around prick points in original board pads. More on this later)
It looked obvious to me that without this material, there would be no thermal contact with the bottom heat sink or there would be a direct electrical short to the naked heat sink.
(2) The connector for the FFC cable from the front panel display has no lock device on the replacement main control board. It does insert quite firmly, but there is no extra clamping pressure against the contacts.
I carefully removed as much of the original white rubber holding material off the mainboard cable end connectors as possible. All plugs seem to seat properly in the matching board connector sockets. There its enough variation in pin count and connector shape it is impossible to make an “in situ” connection error.
All wiring complete, I did a power up test of the system.
I received exactly the same display as the original board, and the same “no communication to the mainboard” error message.
Powered down and removed and firmly reinserted the FFC cable in its non-clamp socket as I assumed that may be the fault area.
(3) I have NOT replaced the FFC cable as I can see no safe way to remove and access the front display panel system. I used a mirror and can see from the rear, what appear to be two recessed Philips (X-head) screws on the back of the of the screen case, but have been unable to turn them, as I seem to not have the proper fitting tool. The screws are very tight. Also I have no idea if removing these screws will cause harm or be the appropriate action.
No instructions have been provided on how to remove and service the video display panel.
On the next (2nd) power up I was presented with the proper and normal start up display ! I was amazed to see all my old print files were still there and the system had all my set-up parameters and the WiFi identity and access password.
SO… all the configuration information must reside in the display computer and not the mainboard control system.
I next decided I needed to do a new new system calibration test. Since everything was now displayed I thought repair complete, all is well - (WRONG!)
Did a “homing” command from the display screen. The print bed descended to the bottom and did the normal “bounce” test with the end switch. Then suddenly a very loud screaming alarm sound came from within the the printer. It sound like a stepper stall but at a much higher sound frequency. (View video.)
At first I assumed the Z axis had stalled at the bottom because (perhaps) the end switch was fouled on the base plate. (I left the base plate unfastened for testing)
I had to manually crank the bed back up to service height with pliers (1/4 turn at a time). This is hundreds of 1/4 turns and is very difficult and tiring.
BTW, I have performed this bed raising task at least eight more times so far in my troubleshooting. (below)
I inspected the switch, cable, and main board plug, no problems. Switch will activate when base cover is down. There is NO problem with the Z switch.
Next homing try, same thing happened (see video). Discovered the sound seem to be coming from the right hand extruder. Actually it is the X1 axes drive motor for the right extruder.
Four more manual bed raisings and wiring inspections of board connectors and re-testing have made no difference. I am trying to be very procedural, but the manual bed crank up after each test is becoming unbearable.
The sound is some kind of oscillation at high audio frequency in the X1 stepper motor. The motor is not stalled and the right printhead can be manually moved with very slight resistance.
I totally disassembled the right extruder as the error message on the screen said it was the print cooling fan. Total disassembly and total electrical isolation proves this is not true. The extruder head was acting like a speaker cone and the sound is definitely generated by the X1 axis stepper for the right head.
Perhaps the exposed pads on the underside of the main board, where the heat sink compound as been re-applied, are some how shorting or grounding circuits on the main board through the heat sink material. That’s a long stretch but at this point anything is a possibility.
I decided next to install all new firmware binary files. The serial port main board binary file loader now functions as instructed, provided me from previous support communications. I was able to upload a new system bin file to the rear com3 USB port to the mainboard.
The display screen up front indicated it was running the current version of its’ print system firmware. I decided to do a new upload anyway from the USB front port and the thumb drive. As it did previous, it runs the update to the 60% point and stopped. No full load.
This leads me to believe there may be some issue with the display system computer. I have no idea of total system interaction. As I said above, I was very surprised to see old print files , the special on-line name I gave the J1 and complete WiFi information preserved after the main board swap.
I love the J1 when it is operating properly. I have made many hundreds of high quality prints. A working J1 is a wonderful IDEX printer. But current issues are becoming overwhelming.
For me, an early nozzle plugging problem turned out to be over retraction when parking the idle extruder. CURA had it set for 10 -12 mm. This jams the extruder when next used. Simple software parking retract variable edit (0 - 1 mm) and all jams gone. It’s NOT the same retraction used for printing.
But all other hardware issues have been electrical. Failed (fold-creasing) of main FFC cables to extruder heads and now communication problems in the firmware and control boards.
The J1 is a very difficult and complex system to disassemble and perform service work. I am a retired computer and electronic control system engineer and over 60 year amateur radio hobbyist (W5EHS). So I am qualified to understand the electronics, operating system and hardware.
Age 76 just makes the physical work much harder. Got into 3D printing to design in CAD and just print. Not to constantly repair or “mod” the hardware. As I have mentioned, cranking the bed up multiple times is actually painful.
I can’t imagine the average young hobbyist coping with these issues.
It may be time for me to look at different printer systems or hobbies…
Update 3/5/24 Snapmaker Support requested I swap wiring between X0 and X1 plugins on motherboard. Excellent idea as this will determine if fault follows the swap and prove it is or is not an issue with the motor or wiring. Watch new video. The problem originates from the motherboard.
Snapmaker support is taking outstanding care with great communication. They are sending another MB. The tests shown here are to prove exactly where the falut orriginates. It's all been good trouble shooting practive. But IS a lot of effort.
The J1S is a great IDEX FDM printer when it is working. It's a complex machine and will require the user to have some skills in trouble shooting and fixing issues. There is no "Maytag Repair Man" in every town in the USA (and world) ready to come to one's door and do maintenance and repairs. It's all up to the owner/operator. ME! :)