Help with DNA electrophoresis

[Dr. M. Rhodes]

Help !

I am tryimg to run nondenaturing polyacrylamide gels to visualize DNA in the range 100-400 bp
WE are using a large sequencing rig with 1 or 2mm spacers . But it aint working

Does anyone have any conditions they have used wich might help

Volts/cm
Current (dont want it to get to hot)
Buffers
Acrylamide concentration (at present doing 6%)

anything else
Thanks
Michael Rhodes
email: mrhodes at crc.ac.uk