Recent content by saipan59

Just discovered that bitsavers has a KDB50 microcode listing: http://www.bitsavers.org/pdf/dec/vax/vaxbi/ The first page shows that it came from Matt Tedone in 1988 -- I remember Matt. It has 'conditionals' for UDA, KDA, and KDB! And other good info. So that means I should be able to figure out...

Yes, you're right. It is certainly possible. And the easier comparison is the UDA50 (M7161), rather than the KDB50. The microcode word format is almost identical. The M7164 designer told me that the M7161 was the basis for the design - the main changes were Unibus-->Qbus, and to make it fit on a...

Yes, Qbus. It's a 2-board set -- the M7164 has the Qbus signals; the M7165 only gets power from the bus. Yes, there is one set of ROMs, but two code "images" in there. The two threads share the same ALU, but have separate sequencers that are active on opposite clock cycles. Yes, the code...

In case anyone is interested, the Museum has put this CVC on eBay. Pickup only in Colorado Springs. The sale benefits a worthwhile non-profit. eBay item number: 145747594264 Pete

I'm checking out this H7225 "constant voltage conditioner" which belongs to the museum I volunteer at. Does anyone have experience with it? What type of installations would typically use one of these? It works fine, although it makes a fairly obnoxious buzzing sound - is that typical for these...

[EDIT: 11/24, not 11/04] Isn't an 11/24 the simplest Unibus PDP? One hex module for CPU, another for memory. As I recall, the BP is a bit unique, but perhaps can be made from a DD11-DK or similar?? Pete

The disk controller board you have is half of a UDA50: https://gunkies.org/wiki/UDA50_Disk_Controller A UDA50 is probably "essential" in a Unibus system IF you will have SDI drives. Pete

I had a VT103 that I bought in the 80's via the 'Employee Purchase Program'. It cost me over $4K. I still have the Q-bus backplane from it, but nothing else. It has an edge connector for the VT100 board to plug into. Check the 103 print set to be sure, but I think the VT100 module (that does...

Hi, If this is what you need, PM me a mailing address, and I'll send it to you. It's apparently 'NOS'. You might as well take the entire holder - I have nothing else that matches it, and I no longer have any complete DEC machines that might use it. Pete

Hi Lee, Can you post a picture of the type you want? My "fuse holder box" might easily have what you need, but I'm unclear which style... Pete

Those referenced PDFs are very useful for a lot of discrete parts - thanks for pointing that out, I'd never seen it before. Too bad it's from 1970 -- a 1985 version would be really nice... See my earlier post above. The Component Index books list basically EVERY part. For the parts on a...

What happens when you explain this to them. Do they ignore you? Surely they *want* to sell stuff...

On second thought, I'm starting to remember that there WAS a printed part number list. My memory is fuzzy, but it was 3 volumes, paperback, gray/brown color. Each volume was about 1" thick, but one of the volumes was closer to 2" thick. Would have been used by folks in Component Engineering, but...

FWIW, the 50-class (bare PCB) is often clearly marked on a board etch, the 54-class (board assembly) may or may not be marked with a paper sticker. I've never seen a list of those PN's out in the wild. And I don't remember ever seeing a printed version. I would suggest that it was never needed...

Here's the bit fields for the UDA50, as seen on the schematic. The KDA50 designer told me that the UDA and KDA have almost identical fields, so this should be really close to the KDA. 00-11 branch addr 12 CROM parity (odd) 13 JUMP OP 1 14 conditional execute 15 SENSE 16-19...