Well, one problem with the 430, as opposed to the Synergy, for example,
is that it doesn't monitor the synthesis, and extend the coupling times.
When I used the 430 a lot, I routinely double-coupled everything, and had
good recoveries every time. It's fairly easy to set it up to double couple,
and I think you might want to try that to see if it helps. Other than that, I
would suggest leak testing the whole machine, inspecting the delivery
valve blocks, and things like that. You do change those in-line filters
often, yes? Terry
>>> David Andreu <andreu@mafalda.qui.ub.es> 09/18/97 03:04am >>>
Dear ABI 430A experts (I hope there are some left!):
I'd very much appreciate your thoughts/suggestions on how to solve a
problem
with our 43OA synthesizer. We've kept the machine in good working
order and use
it routinely for Boc chemistry. Recently we have detected serious
failures with
the small-scale rapid cycle (0.1 mmol) program, leading to largely
incomplete
couplings. The problem exists only with this program. Runs using std1
files DO
NOT present any problems. A brief summary of our prognosis follows:
1. System checks for the A, B and C regs are OK. TFA and DIEA
deliveries are
accurate. Boc-AA is correctly dissolved.
2. DCC and HOBt are measured and delivered OK.
3. Activation proceeds OK (DCU precipitation observed)
4. ACT to CONC and CONC to RV transfers are OK.
5. Problem subsists when a new (from PE) disk with SSRC is used
6. Problem is independent of resin type (Pam, MBHA)
The local PE technicians seem a bit at a loss with the problem. Does
anybody
out there (perhaps PE people on the list) have a suggestion? Thank you
very
much for your attention.
David Andreu
University of Barcelona, Spain