After months of searching I have managed to get hold of a Howtek 4500 in what appears to be really nice condition.
I have done a couple of dry test scans of 6x7 negatives and everything seems fine.
I do appreciate the need to keep an eye on the condition of the drive belt and drum wear pads, but is it sensible to change the PMTs, or keep some in stock, and if so how many do I need?
If anyone has access to a service manual they could email me I would appreciate a copy; more out of interest and for regular maintenance checks than a want to strip the thing down.

Thanks ...Sweep