Looking for parts/info

The KW20 was not used on core-based systems, and was introduced with the MF20 semiconductor memory, so the drawings for the KW20 master oscillator are in the MF20 and MG20 print sets, which are on Bitsavers. DEC used custom DC009 transceivers for the control signals from the M8572 to the KW20 that are used to select the oscillator frequency (25, 30, or 31 MHz, or external). These are the same transceivers used for the Xbus (semiconductor memory bus from the KL memory bus translators to the MF20/MG20 boxes). I've never found any DC009 specifications or other docs, so I have no idea what the signalling is like. The six coax clock outputs are driven in sets of three by two MC10210 ECL dual 3-input 3-output OR gates, with near-end thevenin terminations (voltage dividers) across outputs 2 through 6, but not output 1. It should be trivial to build a replacement if you don't mind a fixed frequency or manually switching the frequency. The MC10210 appears to still be reasonably easy to find. 25 MHz is used for the KL10-PA ("Model A", no section support), 30 MHz is used for the KL10-PV and -PW ("Model B"), and 31 MHz is used for margin-testing the -PV and -PW. The 2065 (or any KL10 with internal MF20/MG20 MOS memory) does not have an Sbus. It has Xbus instead. The Sbus translators (M8519) in slots 7 and 8 of the CPU backplane are replaced by Xbus translators (M8581, unless you have a mixed core/MOS system). The Sbus cables and paddles (slots 2 and 3) are replaced by an Xbus cable that uses an M8572 paddle (schematic and component placement in the MF20 print set). The Xbus cabling looks similar to VAX SBI cabling. I'm pretty sure you got at least one M8572/cable assembly from me, when we were scrounging for missing parts. If you're building your own memory system instead of using an MF20/MG20, it might be easier to use Sbus, since it uses readily available parts for the interface, vs. the unobtanium and undocumented DC009. Sbus uses SN75453 drivers and MC10124 receivers. The Sbus cables and M9006 paddle are nothing special, since all the electronics is on the M8519. The Xbus M8572 paddle has a small amount of electronics to drive the clock select signals over a separate ribbon cable to the KW20, but aside from that is passive. In either case (Sbus or Xbus), you need two translator boards (M8519/M8580/M8581), but one cable and paddle board (M9006/M8572) supports two chained memory boxes. You should be able to get by with a single paddle board, unless for some reason you want to use three or four memory boxes. Eric