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Hello,
I just joined the forum since I'm making good progress with my PRINTNC project. I want to use 4 closed loop step motors (2 steppers for z axis). I keep look around but everyone is using a MESA boards or a raspberry pis with some kind of adapter boards for connecting the stepper drivers.

  I live in Turkey and I can't get anything through customs that's over 30 Euros I can't get the MESAs or the adapter boards for raspberry pis (No shipping to Turkey). BUT I have access to 3D printer control boards. like BTT Manta M8P and MKS SKIPR V1 or MKS Tinybee. Is something possible with these?

I would be very glad if you can point me in some direction. Thank you.

What are the chances of this being a slow SD card issue?
It sure points that way...

To tell the truth, whilst I haven't done any long term testing, I haven't seen this issue of my RPi-400.
When I build the image I put it through the basic tasks, and if I had of seen this issue arise I wouldn't have released the image, I would have deemed it defective and not fit for purpose.
Now we are going to require some more info, what monitor (brand model) screen resolution and such. And just to be sure I would like to know if this is a clean install without any extras added. If you can remember when was the last time you did an update.

And yes the RPi400 should give reasonable playback on youtube and reading pdfs shouldn't pose an issue. When I get the time I'll recheck things but as I said before I haven't seen this issue arise during testing and so far in the 6 months it has been out in the wild no one else has mentioned this.

One thing I would suggest is look at this thread, forum.linuxcnc.org/38-general-linuxcnc-q...l-images-only#325007 and take note of the video issue link & zswap link.

The official LinuxCNC 2.9.4 image for arm64 is installed on a Raspberry Pi 400. There are strange partial graphical glitches in browsers, such as some pages or partial horizontal section of the page not displaying properly, while the rest is fine.

This was tested with Firefox ESR, but Chromium was also installed, and for example, the settings page for Chromium never displays properly. It would appear the underlying text and buttons/links are present but not visible, except by sometimes mousing over them. 

The problem appears to be only in browsers, not other applications. Youtube in either browser is also unusable, with graphical glitches on the player controls (YT buttons like play/pause/settings are either invisible or look corrupt).

Similarly, when opening PDF documents in browsers, the control buttons along the top of the document for Zoom/Download/Save etc are often invisible, but still present if moused over.

Also, Youtube video playback is extremely laggy, and that is including after removing the isolcpu=2,3 option. The goal on the Pi is just to familiarize with LinuxCNC and set up configs, not to run machines on it, so I'm not too concerned about the latency penalty in this case.. 

Has anyone else experienced this problem? 

Honestly, I would just add a  leaded 620 Ohm pulldown
resistor on the back of the breakout card and not make
any further modifications.
 

so a stiff pulldown to fight the pullup of the mesa card for the inputs?

I am using 7c81_5abobx2d firmware with BOB boards on P1 and P2.

Edit:
I did a little bit of digging.
- The relay pin P17 is IO7 of the Mesa ports, which is on the edge of the pull resistor array. I could desolder the array and put it back on shifted by one to remove the resistor of the pin.
- On the BOB there is a 10k pullup array on the relay pin. but the signal comes through a via in the middle of the pullup resistor and the 74HC... I could cut the trace between the via and the resistor to remove the pull up on the BOB
- solder in a pulldown resistor on the BOB (if for whatever reason the flat cable between the Mesa and BOB gets bad).

The 7C81 only has the option of all pullups and all pulldowns
on its I/O ports.

Simplest solution would probably be to add a stiff pulldown (say 620 ohms)
on the relay I/O pin. There is a firmware option for fixed parallel port type I/O
but currently its global (not per port), This firmware makes the parallel port
output pins default to outputs instead of inputs at startup or watchdog bite
What firmware are you using?

Maybe a stupid question, but how do you use the relay on those cheap MACH3 BOBs with the 7c81?

For the inputs to work I need to enable the pullups on the 7C81.
But enabling the pullups makes the relay close as soon as the BOB is powered.

Ideally I would want the relay to be open until linuxcnc is started and I tell linuxcnc to close the relay.

But the relay closing by default due to the pullups makes it unusable, or did I miss something?