On 2011 Nov 22, at 11:23 PM, Colin Eby wrote: I believe this board is nearly identical (or is identical) for the 2116B & 2116C - is it missing from both units that you have there? I will send the schematics for the 2116C power supply, 2116B PS schematic is available in the 2116B manual on bitsavers. Will take photos of the 2116C board if you like. Powered up my 2116C for the first time in a long while, after your last message, and toggled in some blinkenlight programs. Still works, at least.

If the component density isn't too high (and I doubt it would be on a machine of this age), it's often possible to photocopy (or scan?) the track side of the PCB and use that as the track pattern for that side. Then it's just (!) a matter of working out where the tracks go on the otehr side, which isn't too bad given a good photo of the board and a scheamtic. Sure... But presumably the board you make will be a plug-in replacement for the original. So if an orriginal does turn up you could put it where it belongs. All you've wasted is the time and components ot make the replica. you've not damaged the machine in any way. Sicen I suspect HP2116 parts are rare (that's not Ebay-RATW :-)). I think it's worth the effort ot make the replacement. If it were my machine that's what I'd do. -tony

Guys, The original part would be the ideal -- and that's what I'm hoping for. But reality has already begun seeping in! Yes, I'm afraid I've already checked in with Crisis, and I'm in contact with the person who bought out their 21xx stock. It's not looking promising. Though a weekend trawl of their parts bin may yield something. Tony's right, of course. The next best thing is to work up a replacement board. I've already started doing that. I've asked around for photographs from people I know have the 'B' model. Through a combination of photos, schematics published in the old maintenance manual, and Brent's schematics for the C, I should be able to get a working replacement fabricated. An original is still preferred of course, and if anyone out there has one available, I'd love to hear from them. The 2160/61 is a thought. And I do have access to one. I believe the design is substantially different though. The part numbers certainly are. I shall have to peel the covers back on it when I'm out at Bletchley this weekend and compare it's bits with the maintenance manual schematic. It's always possible a board with turn up buried in the uncatalogued collection somewhere. But I'm not optimistic. Anyone familiar with the TNMOC collection will appreciate how challenging it can be to do an exhaustive search at the moment. I've already done a fairly broad hunt. I'm working on sorting/cataloguing all the unmanaged HP gear as part of the process, but most of what I've discovered so far is from the next generation of systems > 1970. The IO cards may be usable, but the power supply design changes pretty substantially. On Wed, 2011-11-23 at 14:33 -0800, Brent Hilpert wrote: -- Colin

On Nov 23, 2011, at 8:58 AM, <arcarlini at iee.org> wrote: You're not kidding! -Dave -- Dave McGuire New Kensington, PA