OK. So today I had my first “Major” issue with my trusty A8.
The Bed Heater connector on the old 1.5 Board decided to detach itself. Not fully, but enough to cause problems whilst printing. Continual “Heated Bed Failure” error messages.
The connector can wiggle about 2 - 3 degrees around centre. So the connection is intermittent at best
I have a newer board, the 1.7, now installed
I have flashed it with Marlin 2.0 and everything, on the printer, is working as it should
The new problem I have now is when connecting to my slicer via USB.
I use S3D, and have done for almost 2 years, without a problem
When I try to connect to my A8 I am now receiving … “CRC Mismatch Connection Failed” error message
I can still print directly from the SD Card, but I would like to connect via USB so I can do my Calibrations
Does anybody know how to fix this?
Did you set the new baud rate in S3D? While most printers default to 250000 (which is a bullshit value) Marlin usually is using 115200, which is a real baud rate.
If 115200 is not working for you, check the configuration.h file. The baud rate is within the first few pages.
About the connector issue. I have the original AnetA8 V1.0 board and it is the same. I resoldered it once just to be sure. On the bright side you don´t touch the connector that much. The bed connector is the worst and may catch fire. Especially if you are still using a configuration where the plug is unsupported. You should solder the heater cables right onto the board and give it support via a cable chain.
Did you check windows wasn´t swapping the port? It (like linux) likes to create a new com port when unplugging/replugging.
So, you are getting text on the screen when powering up? And you can read it. If so, then the problem does not sound like the serial link to me. I mean, if it was, you wouldn’t get readable feedback. I’m wondering if a command is being sent that is not understood. A CRC error normally means “we got the message, but it failed the integrity check”.
That certainly looks like it’s talking to the printer. I think it’s time to try Pronterface; see if it can connect.
BTW, Digipots are Digital Potentiometers.
I would guess the cable is damaged or the usb connector has problems.
The software is talking to the printer and unless the protocol changed, which is unlikely, as I did update to marlin 2 from a three year and more old marlin 1 without any issues, it can only be it.
There is one thing I remember, but I guess it got fixed. The old marlin refused to connect to a host, when the SD card in the printer was missing. It is a long shot, but it took me two hours to figure out that the SD card, which I did not even used was plugged in, but was not connected to the printer due to the click mechanism, which in the end was causing the issue not being able to connect via OctoPi.
@Geit, I’ve been leaning toward a bad cable too, but I think a test with Pronterface would help seal the deal. 'Course, it could be a bad connector on the control board too. I had that happen with my smartphone a while back.
I’ll give Pronterface a try in a cpl of days, after my latest print has finished.
It’s printing off the SD Card no problem, 32hr print in progress.
BTW I’m loving this Marlin 2 install so far (apart from lack of USB connection)
Way more options now available. Especially Bed Levelling > Level Corners
Hated having to do it via S3D Control … Raise - Move - Lower … rinse and repeat
What I don’t get is, IF there is an issue with the cable, howcome I was able to flash Marlin over USB
OR … Is that why it won’t connect, BECAUSE I flashed over USB
I doubt very much that flashing over USB would cause connectivity issues. It could also be the computer, or even S3D. Another thing you could try is Cura.
I would still check the SD card is inserted properly, when connecting via USB. It shows the same behaviour I had about three years
It connects to the printer, OctoPi or in this case S3D triggers an SD card access and the printer firmware resets terminating the connection in the process. Maybe it is no longer crashing the firmware, but well, it is worth a try.
Since then I have SD cards in my printers even as I disabled the SD card support by not compiling it in. Those SD cards just contain the stl and other data files I used to upgrade the printer.
Pronterface connects to the board and everything shows up with the M503 command
And I have full control of my printer from within PF
So why won’t any other slicer connect to it?
Well, at least I can get my Calibrations done now
@Indy_UKCM, this is important information. Now we know the control board is working, so the issue lies somewhere in your computer or in the software. Have you tried another computer?
Also, since you have a S3D license, why not give them a call?
This indeed falls back to be a S3D problem, so I am out. 
Well, except @Indy_UKCM did say he’s tried several slicers & none of them could connect. Hence why I said to try another 'puter.
Thanks for the help guys
We may not have found the solution, but at least we found the main problem
I will let you know the outcome after I contact S3D
As a side note
I’m not sure what the weather is like at your place.
But my printer is not enclosed and the Hotend Temp (on power up) is 6C damn that’s cold
It’s usually at around 15
Hah! I’ve lived in places where it gets to -40C ?. Weird fact: -40C & -40F are the same!
If you have 1 available, I really think trying another computer would be very useful.