Raymond,
Thanks for your reply. The one that I was interested in didn't have a date code sticker like you mention.

Most of the responses here don't really address my original question. I've got a 60's PM61500 DP and a 70's PM66 TS so I'm in agreement about older tools usually being better (with the exception of 2000's Deltas that have no parts available). I'm willing to entertain other ideas but don't see anything availbale to me that will suit my needs. I'm in the Midwest and probably have better access to these older tools than most folks here. Can you tell me the name of air filter built before 1990 that is readily available, has 1 micron filters, and has a timer to continue cleaning while you go inside for dinner (rather than letting all the dust settle out on everything)? I know I can add a light timer on the outlet for $20...I can add a remote to the outlet for $40...I can retrofit a filter close to 1 micron ($?)...but that's not what I want.

If those that talk about older tools can direct me toward an older alternative, I thank you in advance!