Chromatography Forum

I made an attempt to upgrade my Waters 486 detector to a pda detector, by buying an old 991 detector, which was a lot cheaper than a 996. I then found that a 991 detector's interface connection is different from IEEE 488. My system uses IEEE 488 connection from a lace card to a 600 pump and a 486 detector. I called waters tech support, but got no help.

It'll be too sad for me to be stuck with a 991 that I cannot use. Does anyone know what kind of cable or additional boxes I need to buy to use a 991 detector?

Thanks!
Robert

Long ago, Waters made (or supplied) a kit that service engineers used to modify the 991 for use with the IEEE-488 interface / cables. The resultant detector was called the 991M. I know this because I had just such a unit. It was returned from whence it came in late 2000 or thereabouts when I went to the 996.

My recommendation: Find a good secondhand 996 or 2996. The 991 was a good detector, but isn't nearly as sensitive as either the 996, the 486, or the 2996, all of which I've had in the lab. The 996 is approximately on par with the 486. The day I decommissioned the 991, I measured the difference in signal to noise between the 991 and the 996 on the same system with the same sample and MP and was amazed by the results. You'll be a happier chemist, I promise.

Thanks juddc for the info. I can probably use the 991 for semi-prep work, but I need a 996 for analytical runs. I happen to have a spare lace card that has a IEEE 1284 (like for printers) connection. It's an ISA card and is very large. Can I use this card for the 991?

For using a 996 detector, do I need a PCI version of the lac/e card? The card I have is an ISA card (supposed to be a multi-instrument version) with a 488 connection. Thanks!

I honestly do not know for sure, but I think you might. A Waters service engineer should be able to assist you. In the meantime, I'll try to dig out some old info.

The 991 was long ago discontinued and (I am pretty sure) is not a supported product any longer. This means service and parts are hard to come by. As was mentioned earlier by a 996 or 2996, the 2996 would be BY FAR the better choice. The 996 will soon fall into the catagory of no longer supported. The 996 was long ago discontinued, Waters usually stocks a 5-10 year supply of parts and such, but I am pretty sure (I am not really commiting to much really am I), that 5-10 years is up. The 2996 is still the current PDA.