Q: Hi, I'm using a Laserwriter 8500.  Got a couple of questions ...

1. You can only do double-sided automatically if the duplexer, a complicated mechanical option, is installed. In printer set-up, you must specify that the printer has the duplexer installed as a feature.

The duplexer whips the one-side-printed page into a turn-around track and re-feeds it with the opposite side available for printing, so you must print "collated".

If you do NOT have the duplexer, you will be forced to do "poor man's duplexing". That is, print only the even pages (possibly in reverse order), then re-stack the pages and print only the odd pages.

I found it helpful to draw a diagram of what the intermediate and finished output would be. As I am printing, I refer to the diagram or recite, "print the even pages oddly (reverse order) then the odd pages evenly". This mantra works for a printer that does NOT flip the pages over when picking from the tray. All techniques depend on knowing "which side up" both the leading edge, and the face to be printed.

A mis-feed or bad assumptions will spoil a lot of half-printed pages, so start by doing smaller batches, then expand the number of pages as you gain confidence in your ability and the printer's ability to do more at once. Only even or only odd pages is an option in the print dialog for every postscript printer.

2. Apple Printer Utility (which runs under OS 9 or "Classic") can tell you about all the printer features.

3. a) ebay
b) http://fixyourownprinter.com
post a request for help in their forums, or send an email asking for a quote on the part. Be as specific as possible.