Hi Tony, Using the status control panel, with the a tube on and with the flow switch set to run, you can tell what laser power you've got (should be pretty close to 15mW), what sample pressure you've got (should be around 6-6.1 Volts on low flow rate, lower than that on High flow rate), and whether your sheath and waste tanks are OK (ie not empty and not full respectively), and your cytometer should be "ready" (not on standby or "not ready"). Supposing that your readings are in these ranges, take the tube off and the sample voltage should rise to around 10.23 (indicating no sample pressure). After a few seconds, the laser power should drop to less than 5mW and the cytometer should go into "Standby" in the status panel. If this all happens, the chances are that the sheath fluidics and laser are OK. If the reading are different from these, drop me a line with the details and I'll see if I can make sense of the result. The next suspect is the sample probe: with no tube on, swing the tube support arm under the probe - you should see a puddle forming as the sheath drips back out - if you don't, you can remove the probe assembly and back flush it (and/or sonicate it). Try using a cut off butterfly syringe needle attached to a 1ml syringe to flush it with (larger syringes are less effective), and keep flushing until you can get a fine jet coming straight out of the pointed end of the sample probe that stays coherent over a distance of two feet or so. If the tube is not blocked it could be the capillary that carries the sample through the laser: try repeated drain/fill/backflush.drain/fill/run cycles,while observing the conical chamber and the laser intercept point - the sample chamber should empty on drain, fill on fill,and partly empty on backflush on run, the intercept point should be stably illuminated. If you seem to have a persitent block at this stage, you can remove the polythene tubing thaqt gathers the waste at the top of the capillary and flush buffer/detergent through the connector using a syringe and suitable silicone tubing. If your everything above checks out, it might be worth checking the hydrophobic filters that protect some of the air-lines, if the one that is connected to the sample probe gets wet, it acts as a barrier to air flow allowing the pressure to build up behind it rather than in the tube - at the same time your tube will probably fill up with sheath. I hope you find this helpful, drop me a line if you need any more info, Ray > From: Tony Schountz <tschount@mesastate.edu> > Organization: Mesa State College > Date: Wed, 17 Jan 2001 19:32:45 -0700 > To: Cytometry Mailing List <cytometry@flowcyt.cyto.purdue.edu> > Subject: No flow on cytometer > > > Our BD FACScan seems to have flow problems. It hasn't been used for a > couple of months, so I think it's just clogged lines. But since we don't > have a service contract I was hoping the group might have some > suggestions as to get the the lines unclogged. In the event this isn't > the problem, what else should I check out? > > Thanks, > > Tony > > -- > Tony Schountz, Ph.D. > Department of Biological Sciences > Mesa State College > mailto:tschount@mesastate.edu > > >
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