The 16500C turned up today but was dead on arrival. Just getting a pathetic wailing noise from the CRT section. Will take a look at the power supply over the weekend. The case was also banged up pretty bad so just ordered another as a parts machine that has a good case and all the cables and pods etc.
All The Gear No Idea ![Flogging A Dead Horse :horse:](https://www.eevblog.com/forum/Smileys/default/DeadHorse.gif.pagespeed.ce.kBWvHKqCd1.gif)
The 16500A, 16500B, and 16500C all share the same power supply, CRT, and main chassis and top, bottom, and side panel components. The CPU boards, front and rear panels, floppy drives, and some internal cables and brackets differ between the three. HP sold an E2479A upgrade kit that would upgrade a 16500A or 16500B to a 16500C which supplied only the parts that differ.
If you have a working 16500A and a dead and banged up 16500C you should be able to build a working 16500C if it is just the power supply and/or CRT of the 16500C that is dead. Removing the power supply from the 16500A and swapping it into the 16500C for testing or permanent replacement is not too complicated. You don't need much other than T10, T15, and T25 Torx screwdrivers. It is not too much more difficult to also swap the CRT, it just take a bit more disassembly and reassembly. I've done this a few times and for the most part you can figure it out without even looking at the service manuals, although looking at the service manuals does help.
Attached is the E2479A upgrade manual which has some helpful information about the parts that differ between a 16500A or 16500B and a 16500C along with some diagrams and disassembly and reassembly notes.