Locking up mid print

Occasionally Repetier locks up mid print when connected via usb to my laptop. I have an Arduino mega 2560 and Ramps 1.4.
I have got a card reader on the printer. When I print direct from an SD card without the laptop there is not a problem.
It locked up again today and I found it had lost the com port. Apart from rebooting the pc and starting again all over, I have found that uninstalling the com port and re installing it re establishes connection. The print is obviously ruined. Not very satisfactory.
I have minimised as best I can the background processes running on the laptop and altered power saving options so it stays on all the time.

I get this problem too with Repetier, but only when I've left my WIFI card plugged in (mine is an old-school PCMCIA card).

When it's unplugged it's very reliable. leave it plugged in and it is almost guaranteed to stop for no real reason.

it's something for you to try at least.. it solves my problem but you may have some other issue

Thanks T0mmm. I will try disabling my wifi to see if that does the trick. My wifi is in built in though.
I have an old Panasonic Toughbook running XP.

This is something that has nothing to do with the host. It is a usb component or driver that gets lets say out of sync. Maybe from crosstalk like a WIFI that is nearby, unstable 5V, noise from motors, something like that. Sometimes a different usb cable already helps. Some are better shielded then others and it can make a difference. Sometime sit is enough to use an other way for the usb cable.

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I have found out already that there is a big difference in the performance of usb cables. The most stable one I have used is a clear cable where the screening can be seen inside. The worst was a mini usb cable going to a hub.

Repetier: are there any settings I can alter in the software to reduce the incidence of this happening eg slowing the baud rate down? I am using Marlin firmware - any advantage moving to Repetier firmware - specifically for this problem?

No, there is nothing you can do on the settings side. Serial settings do not affect usb transfer. that happens on the board between the usb converter and the avr chip.

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Repetier-Software - the home of Repetier-Host (Windows, Linux and Mac OS X) and Repetier-Firmware.
Repetier-Server - the solution to control your printer from everywhere.
Visit us on Facebook and Twitter!