MicroVAX 2000

From: Jack Peacock <peacock_at_simconv.com>
Date: Mon Jun 22 19:19:08 1998

> This one is a Model 625NT-AA, and comes without harddisk. It appears
that there is a resistor board installed to provide a load comparable to
the drive on the power supply. According to a rather sketchy spec sheet
that I d/l'd from DEC, it can handle a maximum 318mb local disk. Based
on the 53C80 chip installed, I presume that the drive should be SCSI. >

Not exactly, the SCSI port is only for a tape drive, a TK50Z (an early
ancestor to modern DLT drives). A uVAX 2000 uses MFM drives, either a
Microplis 1325/DEC RD53 (70MB) or a Maxtor 2190/DEC RD54 (159MB). In
order to load VMS you really need the RD54, 70MB is too small. The HD
controller is the 40 pin SMC chip on the motherboard. Oddball MFM
format, not compatible with WD HDCs, but the 2000 has a formatter in the
ROM. The 318MB figure comes from using two RD54 drives (159 each).
 
> At the rear of the machine are three sub-D connectors, one each
25-pin, 15-pin, and 9-pin. What are their functions? The 15 and 9 are
presently encumbered by a plugin box that has three RJ45(?) connectors.
Network link? >

The 25 pin is the TTA2 port, RS423 (close to RS232) with full modem
support (sort of). The 9 pin is TTA3:, another RS423 serial port for a
local printer or terminal, but not wiored like a PC 9 pin serial. The
15 pin is for a workstation cable and carries the video (the coax
connector on the little box), plus a keyboard and mouse connector (TTA0:
and TTA1: serial ports). They are not RJ45s. You should also have a
BNC coax connector for 10Base5 thinwire ethernet.

For more info check the comp.os.vms and comp.sys.dec newsgroups, they
have lots of FAQs for uVAX 2000s. I don't know the URLs but if you post
a question on one of the ngs they will direct you to the web page.

BTW, I might have an expansion memory board left for a uvax 2000, i'll
check the old DEC scrap box. IIRC it brings one up to either 8 or 14MB
of RAM. (a uVAX II maxes out at 16MB of RAM)
        Jack Peacock
 
Received on Mon Jun 22 1998 - 19:19:08 BST