Info needed: VAXStation 3520 & others...

From: Roger Ivie <>
Date: Sat Jul 26 11:42:22 1997

> 1st: (the biggie) VAXStation 3520. 'Cube' configuration, apparently 4
> processors

Four processors would make it a 3540...

> , 64meg of ram, a TK70 and controller, one board that appears to
> be the interface between the processor bus and the three Q-bus slots in
> the chassis,

How much stuff is on the QBus adapter board? There were two versions: FTAM
supports only the TK70 controller (is you TK70 attached to QBus or to SCSI?)
and FQAM supports any random QBus module.

FTAM is a simple module containing only a few chips; FBIC (interface to the
backplane) and CQBIC (CVAX -> QBus adapter) being the only really big ones.
I believe there was also a clock generator chip, but not much else.

FQAM is chuck full o' goodness. It his a prom-based microcode machine to
run the module and lots and lots of PALs.

> and a board on the processor bus marked "I/O Module" with two
> 50 pin headers on it.

The connector which goes out the side of the backplane is SCSI. Although DEC
used the DSSI chip on this module, they only supported SCSI; the DSSI chip is
capable of doing both.

The connector which comes out the front of the backplane goes to a distribution
panel which provides:

  - Four serial ports (console/printer, modem, mouse, keyboard)
  - Ethernet (AUI and BNC)
  - Diagnostic code display (one 7-segment LED)

Unfortunately, I don't know the pinout of the cable; I don't have a printset
for the 3520.

> There also appears to be a space for what looks like it would have been a
> three board video sub-system (which has been removed).

Three boards is correct. For extra fun, it has its own embedded MicroVAX II...

> Aside from the basic power/control cabling, and the cable to the TK-70,
> there are no other cables in the unit at present. (and no place to plug in
> a terminal!)

The terminal plugs into the distribution panel which plugs into the I/O module.
Received on Sat Jul 26 1997 - 11:42:22 BST

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