Well, I've got the Greaseweazle software to run, but I don't know why,
which is hardly encouraging.
Installing various Windows updates, downloading .dlls, and puting the
latter in various directories changed the error messages but it never
actually worked. But downloading the latest Greaseweazle software did,
it ran first time. So no idea what I was doing wrong (maybe 32 bit
.vs. 64 bit Windows applications?)
I can now get the list of commands when I run gw.exe. And can get help
on them using the -h option. I've not tried connecting a drive yet,
but the software can find and talk to the board (the green 'activity'
LED turns on). For example 'gw rpm' which is used to check the drive
speed by timing the index pulses times out and gives a 'no index'
error which seems entrely reasonable.
However I am not sure if I'll be able to use it. There is one very
important thing missing : DOCUMENTATION. The 'wikii' on github is
ridiculously incomplete. There is no user manual or man pages. The
software source in python (a language I've never used) has very few
comments and is not clear at all.
It's not clear to me exactly what all the options are for, and when to use them.
in the last weeks my last two working UltraBooks died. Today I investigated the problem
and obviously in these RDI made notebooks, the NVRAMs not only contain the boot information,
the host ID and the MAC address but also the hardware configuration.
Hence: Once the NVRAM is completeley dead, absent or replaced, the unit will not
start up any more - it gets stuck in the power on test BEFORE the screen shows any
Do anyone out there have got UltraBooks or UltraBooks IIi up and running? Would
highly be interested in a dump of the NVRAM/Timekeeper!!!
The failed first generation UltraBook are (DS1643 NVRAM):
(*) U20-14-9-512P with three (!!) hard drives, no battery port
(*) U20-14-3-128B two hard drives, battery port
And my beloved UltraBook IIi (TimeKeeper DS1553-070)
(*) U40-14-1X-1024C one harddrive, battery port and creator graphics.
Reply here or PM erik(a)baigar.de,
( o o )
| Dr. Erik Baigar Inertial Navigation & |
| Salzstrasse 1 .oooO Vintage Computer |
| D87616 Marktoberdorf ( ) Oooo. Hobbyist / Physicist |
| erik(a)baigar.de +------\ (----( )---------------------------+
| www.baigar.de | \_) ) /
So advice to all owners: Backup your NVRAM contents and I'd be more than happy
to get in touch with you!
Not affected seem to be the PrecisionBooks (e.g. H16-12-8-512L2, two hard-
drives and battery port) as they do not contain an NVRAM/TimeKeeper.
At Mon, 18 Sep 2023 10:55:13 +0200 (CEST) Christian Corti
>as it will be soon of importance to us, I am seeking for the systems
>engineering manual and drawings, well, everything about the IBM 727 tape
>drive (not the 729!). I especially need the module locations charts and
>the module schematics.
Just a few weeks ago I donated to the Computer History Museum a set
of 14 original IBM black binders of "Type 7xx" manuals from the
1950s, including the 727. That one is likely to be the same as what's
on bitsavers, but since it's no longer in hand I can't check. They
probably haven't made it through the CHM cataloging process yet.
Here's a question for all our Computer Museum curators.
Have any of the old GEAC Library systems ever been salvaged and put into
a museum? They were curious boxes and I think would make a nice addition
to a collection.
I have some open slots in some of my racks. I do have some old DEC
rails, but I have a fair amount of equipment, from both DEC and other
manufacturers, for which those rails are not suitable.
Does anyone have any specific recommendations for shelving? (where
equipment could just be slid on top of, if the equipment isn't too wide
- some pieces are very close to 19 inches all by themselves, and were
designed for front cantilever style mounting.)
Would also be interested in specific recommendations for the following:
DEC VR14 (I have one on a PDP-12 with proper rails, but have another to
mount and don't have proper rails for it)
HP 88780 (Perhaps a shelf is the best bet for these?)
Same place as last year in the big parking lot across from Brookdale and
down the street from InfoAge Science and History Museums.
We have Southern Monmouth County Firehouse museum selling food and drinks
in the middle.
This is a fundraiser for both museums (VCF and Firehouse museum) which are
both part of InfoAge.
All the info is here: https://vcfed.org/vcf-swap-meet/
VCF National Board Member Chairman & Vice President
Vintage Computer Festival East Showrunner
VCF Mid-Atlantic Event Manager
Vintage Computer Federation is a 501c3 charity
The DEC H7441 regulator is a relatively complex circuit using 2 x 555
timers, 2 x LM301 op-amps, 2 x transformers and 2 inductors
I am struggling to understand how it is meant to work and was hoping to
find a maintenance manual for it.
Could anyone with such a manual please help?
Alternatively is there another explanation of the operation of this or
similar types of circuits?
The circuit implements a switch mode supply.
One of the two 555 timers operates as an oscillator, the second I think
operates as a monoflop with the pulse length controlled via one of the
Overall the circuit seems very complex and while I understand parts of it,
other parts are mysterious.
In particular the top left section around Q1/Q2/Q3 and T1/T2 and E3 is most
I did not find anything remotely similar in "The Art of Electronics" from
Horowitz & Winfield.
The H7441 schematics are available from here:
Thanks for any help or suggested reading material.
I bought this giant GCR tape drive on eBay five years ago,
hoping to be able to use it to extract analog signals from 6250 BPI
tapes to feed into my decoding program.
I failed to figure out how to get the right signals out, and
eventually abandoned the project. I now need the space it takes, so
I'm offering it for free before consigning it to the landfill. It's
big (20" x 24" x 30" on the wheeled stand I built) and heavy (160
lbs) so I won't ship it. Pickup only, on the San Francisco peninsula.