I think you need to check the solder joints on the 030 processor and memory slot.
A 030 processor heats a lot (not like a 040, of course), and after some years of heating-colding cycles some pin can develop a bad contact. Specially if it is a PGA unit. PLCC chips don't suffer this issue too often.
Another good candidate are the pins of the accelerator itself. Just carefully pry 'em to make better contact with the edge connector of the 1200.
