Beckman sequencer problems

[Tom Vink]

On Tue, 31 Oct 2000 11:40:53 +0000, Ivo Rieu <irieu at sci.kun.nl> wrote:

>Hello, I would like to come in contact with people that are using a
>Beckman CEQ2000 sequencer for DNAseq.analysis.
>The problem we have here is that the result is very variable. If we do
>the same sequences multiple times, one may be very nice, the other crap.
>
>We have the feeling that we are working on the edge of what the
>sequencer can handle, so sometimes it is just allright, while the next
>time the sample we try to sequence is just out the range the sequencer
>can handle. And we don't know wether what is out of range is the amount
>of template, the salt or something else that is not optimal. The most
>observed thing that goes wrong is a unstable, decreasing current, and a
>very late loading of the sample on the column (what is cause and what is
>result?).
>- Any idea what we do wrong ?
>- Maybe someone has made some modifications to the original protocol
>that improve the sequencing ?
>- ??
>
>Ivo Rieu
>Dept. Plant Cell Biology
>University of Nijmegen
>The Netherlands
>irieu at sci.kun.nl
>

This smells like overloading. Try diluting the sample (1:5- 1:10) or
reduce the injection time and run again.