HP 1000 M series on Ebay

From: J. David Bryan <jdbryan_at_acm.org>
Date: Thu Jul 8 11:18:04 2004

On 8 Jul 2004 at 0:44, Jay West wrote:

> I noticed this the other day... I'm a bit confused as to it's lineage.

Would you have a URL to the picture (I'm not an e-Bayer :-)?


> First, the M series has a unique keyswitch, unlike the E and F series.
> In the E & F, the keyswitch is nothing more than a latch to open the
> front panel. On the M series, the front panel switch is electronic,
> selecting R (reset memory I think), Off, Standby, On, and perhaps Lock
> (going from memory).

R, Standby, Operate, Lock.

The front panel key changed from an electrical switch to a mechanical lock
coincident with the change from the "A" model power supply to the "B" model
supply. The M- and E-series were produced in both "A" and "B" versions
(models 2105A, 2108A, 2112A, 2109A, and 2113A, superceded by the 2108B,
2112B, 2109B, and 2113B). The F-series was produced only with a "B"
version supply, as far as I know. The "A" power supply had the line switch
on the rear of the unit. The "B" power supply mounted an internal line
switch and a separate "Lock/Operate" switch on the front of the supply
behind the front panel that replaces the "Lock" function of the original
front-panel switch.

The front panel itself underwent a number of cosmetic changes. As I
recall, the "A" units were marked "21MX" and "21MX/E" on the front panel.
The "B" units were marked "M-Series Computer," etc. The HP badge tended to
move around too from revision to revision.

(My company had one of the original M-series units, i.e., before it was an
"M-series." The power supply was subsequently upgraded to a "B" unit,
necessitating a corresponding front panel change. So my unit originally
had the electrical switch, and now it has the mechanical one.)


> The one on ebay has no such markings on the front panel. This would
> make me think E & F. But the front panel is clearly from an M, as it
> only has the ABSTPM registers, not the special register mode (index
> registers, etc.).

Could be a 2108B or 2112B.

                                      -- Dave
Received on Thu Jul 08 2004 - 11:18:04 BST