Xerox D-series workstations

At 7:19pm -0600 1999/11/07, Mitch Wright wrote: Depends what you mean by "laying around". We're still using the same basic software (with improvements over the years, of course). Some clients have rights to distribute them (in binary form) on their own terms, so there may be some available somewhere, but I don't know. Unfortunately I am stuck with enough NDAs that I'm not even sure which past example I could name. Purely out of curiosity (and not because I intend to sell mine; I don't) I checked ebay; someone sold a Daybreak for about $100 recently. Compared to ebay prices of other things, this suggests they are not *too* rare. I don't even want to *think* about how much I could sell the 8010 for there, if I were to invoke the "S" word (even though mine has probably always run Lisp, and is, by its memory and disk, clearly a late instance as well). Don't tell me; I want to keep it :-) A co-worker picked up the other of the two available Daybreaks; if he gets tired of it, I'll let him know you might be interested. On 1999/11/06 at 7:15pm +0000, Tony Duell wrote: Part of the manual I've read mentions that the 80186 loads the control store during booting "and debugging". I haven't yet seen how; I suspect the details are not in any manual I have. In most of North America, a flat line charge includes unlimited local calls; that's why people here throw around binaries with abandon. "The keyboard/interface uses the receive half of the i8251A interface chip" suggests it's one-way communication. "... receive from the keyboard as a differential signal pair by a 75176A receiver chip." I don't know; does this imply RS232-compatible levels? "... asynchronous serial interface with a data rate of 9600bps". I do not see the protocol documented, but by the time you get around to your machine, I should be able to hang my keyboard and mouse on some serial port and/or logic analyzer to work it out. After removing the transformer, I believe I've confirmed shorted turns on one half of the primary. Assuming no shorts in the secondaries, would this not mean that the voltage I measured (15V) is an upper bound on the correct voltage? [moved:] I'm not sure I can do this accurately enough; the outermost layers seem inextricably stuck in some hard resin-ish stuff. It appears to drive half of the front panel board -- the non-LED part. Now, there's a 5V regulator (SG340K-5) there. The output is clearly Vcc for the TTL on this half. The ground is clearly GND for the TTL and is connected to one line from the secondary. The input of the regulator -- I might be wrong again but I've double-checked -- is connected to the other line of the secondary through a single diode (in other words, it seems to be a half-wave); there's a 1000uF to ground. So, one of the things I need to do is keep the regulator happy, which seems straightforward; the question is whether the rest of the circuit imposes tighter constraints. I can't easily trace it all because some traces are hidden by the soldered-in TTL or the capacitor glued across vital parts of the back of the board, so I'm trying to go by what I can see and by considering why it's there. I can only think of two reasons why this might need AC rather than just using the main power supply. It might be a power-fail indicator, but I think that's implausible; since the machine has semiconductor memory and power-hungry disks, there's nothing it could *do* on power fail. And it does not seem consistent with the parts on the board. But if this *were* the case, it would presumably tightly constrain the required secondary voltage. The other possibility I can think of is that it's a line-based clock/timer. There are further diodes and resistors feeding (in a manner I can't fully trace) a pulse generator (74123) whose output appears on the cable from the front panel to the I/O board, and a trigger/inverter (7414) which, I think, drives counters (74LS163) leading to a flip/flop (74LS74) whose output likewise appears on the cable. Does this sound plausible? And would it impose any tight constraints on the transformer output? -- Kevin Schoedel schoedel(a)kw.igs.net