Mystery LSI-11 board

tom> Well this is a qbus board as it came out of a qbus chassis and tom> the grey handles do have DEC on them! But I agree I think this tom> may be a third party/prototype board! However there is an tom> assembly number and other production artifacts that lead me to tom> believe this is not a prototype board in the strict sense. One possibility is that it's a third party board with handles manufactured by DEC attached to them. DEC sold those handles separately, and you could just attach them to your own board... Something to check is whether there's a module number on them. Standard DEC practice is to stamp the module number on the handle. Module numbers are normally a letter plus 3 or 4 digits; the letter matches the color: M-maroon, W-white, G-green, R-red, and probably others. M were the later ones, with ICs on them (as opposed to R which have either discrete transistors or, maybe, small scale TTL). So the M series module codes includes large modules with cast metal handles, as used in big VAXen. Those aren't actually maroon in color (more like grayish metal), but they still have the ID on the handle. Yet another thing to look for: DEC boards have a DEC logo ("digital" in 7 blocks -- unless it's quite old) somewhere on the board, almost certainly near the edge. paul