Bernina Activa 230 stops sewing after a minute or so. The display goes blank but the backlight and sewing light are still on. This happens on all stitches. It comes back on when I switch it off and on again, but only sews for a few. Any suggestions short of taking it for repairs?

it sounds like a computer problem. I suggest taking the machine to some other repair shop and see what they say.

sounds like you bought someone else's problem, it could be mechanical or if the machine has a computer, that could be the problem, it would be a good idea to have the machine checked since it is used...

Please be advised that the newer machines (Classic models) such as the 130-180 and up, have a totally different geometry. This is to say that the older machines have a shorter distance from the center of the presser bar to the needle center. The newer machine design was increased to provide space for needle threaders etc. Older machines will use an older Walking foot model (still available).

Could be almost anything ! Do the usual simple checks - fuse in the mains plug (should be 3A), have you got another piece of equipment (radio etc.) that uses the same 2-pin plug for power - use it to check that the mains cable is OK. If the mains cable is OK, it maight be the switch on the power supply module or the power supply module itself ('L'-print), but could be more ... check if the sewing light or display backlight is coming on, but if completely dead, your only solution is to get it checked-out by a Bernina service agent.

Lets start at square-one. Have you checked the plug fuse ? Have you checked that the 2-pin mains plug is firmly inserted into the socket on the back of the machine ?
If yes to the above ... are there any lights on at all ... sewing light, display backlight ?
If it's completely dead, it's most likely the power supply 'L'-print which is a separate module screwed into the back of the machine below the spool holders. Your best bet is to get the machine checked-out by a Bernina service agent.

Unfortunately this could be a number of reasons, ranging from simple to hard. Taking the simple first - make sure the 2-pin plug is properly inserted into the machine - if it stops, try wiggling the plug first to see if that 'resets' the machine. If it's OK, it might be the switch on the power supply - I've had a couple that needed replacing, but in all honesty, the problem is probably internal and could range from a poorly-inserted plug on the main control board, to a component problem on the board itself, which could be costly to replace. Is your machine still in warranty (2 years on electronic parts) - if-so, get it checked-out by your Bernina service agent, just in case ... dont go messing-about with the machine yourself. Before doing this ... check exactly what happens when it stops sewing ..... I assume that the foot controller doesn't make any difference ..... check if the sewing light is still on, or the display backlight, and is the display still showing any information, or has it gone blank ? Does it happen on all patterns - straight/zig-zag etc. or a memory pattern ? This may help to identify the likely cause.

see your local dealer and tell them you have a bad power board. or l-print. this is a known issue and bernina is covering it under there 5 year warranty. the 5 volt output is faulty on some some models

Definatly it is an electronic issue. Have the cables checked to be sure there weren't any pinched between the covers etc. And that the plugs on them are seated properly. This they should do naturally. I have also seen this before when what is called the EEPROM chip went bad. Screen lit, no info. The EEPROM is a small chip, black and rectangular on the S-Print board,The EEPROM stores all the information for the machine to work. The screen will light but no info on the screen if its bad. Before replacing a whole circuitboard I would suggest replacing this. It just plugs and unplugs from the S-Print and much less expensive.
If your not feeling all that trustworthy if the tech can do it then ask that it be sent to Bernina in Illinois and repaired. It could take 6 weeks though.

I have the Activa 131 and while the needle is made to stop in the up position, all you have to do is push the bottom of the peddle quickly with your heel and the needle goes into the material and stays until you start sewing again. Hope this is helpful.

Unfortunately this is a purchase site. The closest I could get would be for an Activa 220 230 240 . You can download the manual.
Check the picture on no. 7 and see if this isn't your machine.

http://www.sewingmanuals.com/Sewing_Machine_Manuals/Bernina.htm
Hope this helps. Luck!