I've got a 453 (serno>20000 less than 453A so 50MHz unit) here in the UK which is now officially dead as of 30 mins ago. Triggering problems, replaced pots, fresh tasty FETs and some other fried components, power supply just blew two power transistors, a winding and melted a cap on power on so I'm giving up on it.
If anyone wants any parts, mechanical, electrical or other please PM me and I'll strip them out, test them (if possible) and send them for a negotiable price. Most of it is in a good working and cosmetic state apart from the PSU by the looks. Fan works as well for ref (I know these die lots).
I'll hang on to it for 12 months so if this thread gets old, don't worry I probably still have it.