Early 3458A A9 ref, T106382=LTZ1000A ?

[Cerebus]

The thing I find really annoying is that, although all the components HP used got HP proprietary part numbers, most standard parts also had their standard part numbers called out in the service manuals (for a certain era of manuals) - except for the ones that didn't. So you've got a good chance of repairing old HP kit, unless the particular part that failed is one of the few that only had a proprietary part number, then you're left guessing or trying to characterise the failed part from a working part and then scouring datasheets for a part that matches. Grrrr...