Smears after transfer - (Jul/20/2009 )

Hi, I use Bio-rad semi-dry transfer blot. I usually transfer 2 minigels together and it sometines works absolutely fine for both gels and other times the right or top part of one of the gels shows smears after ponceau staining (despite transferring in exactly similar conditions). Our transfer device is very old and seems to be acting temperamnetal and I really like to put the blame on it but these smears do not always appear at a specific section of the transfer plate. Any ideas on why this is happening?

oops, I menat the right or top part of the membrane shows smears

I suspect that the plates are slightly warped so that the gel/membrane sandwich is shifting slightly or allowing some circulation of buffer between the two parts so that the proteins appear to be smeared.