I am working on an unknown status Persci 299 drive and one of the two
drives is locked closed. Is this a "park" of some kind or is the drive
broken? If it's a parked drive (only the drive 0 side) how do you unpark
the drive? I can't seem to find any info on this. If I find anything I
will post my findings.
Thanks in advance
Bill
The DEC DF02 (300 Baud) and DF03 (300/1200 Baud) modems appear to be
singularly lacking in online documentation. In the case of the DF03 those
would be:
EK-ODF03-IP - DF03 Illustrated Parts Breakdown
EK-ODF03-PS - DF03 Modem Pocket Service Guide
EK-ODF03-UG - DF03 Modem Users Guide
Similarly for the DF02. (Note that the actual designations may use a zero
rather than a capital letter O in the 4th position; references are
inconsistent.)
Does anyone have access to these documents? The only, and only slightly,
useful technical documentation I've found are within the KC780 documentation
(EK-KC780-TM-007_Jul84.pdf), which illustrates the required settings of the
two pairs of DIP switches (or jumpers) on each of the two DF02/03 internal
modules but doesn't define any of those settings. The functionality of the
front panel push-button switches is not described either.
Leads, experience, etc. appreciated, thank you,
paul
Gents,
I've been doing logic debugging (on a fairly primitive software defined radio I designed back in 1999) with an old Philips logic analyzer. It's not bad, certainly fast enough (I need 100 Msamples/s, it can do twice that) and it's more than wide enough (I need 32 channels). But its capture memory is microscopic so I struggle to see more than one or two transactions, and I need to see more than that.
Some poking around shows various USB-connected logic analyzers for quite low prices, and a number of them seem to have suitable specs. I also ran across sigrok.org which seems to be an open source logic analysis framework that can drive a bunch of those devices. Nice given that too many of them only come with Windows software.
I suspect there are others that have not too expensive logic analyzers and might be able to offer up suggestions or product reviews.
paul
As part of fixing the Pro/380 I dug out and decided to get running my
two Intel systems. These are Compaq Deskpro/XE systems. One is a 4100
which has an Intel 486/100 (25mhz, quad clock), the other I upgraded
with a Pentium P524T overdrive chip at 83mhz (33mhz external clock).
The P524T was an interesting duck: It's a 5 volt pentium, 32 bit
external bus but they did double the amount of 64 bit on-chip cache so
it can perk along quicker than one might think. Not many were sold, but
I have one and there you go. It even has a little fan on the heat sink
that is powered off the chip. Cute.
The Deskpro/XE's were great systems, slimline, Compaq business audio,
QVision video interface with 2mb of RAM, IDE drive, and oddly enough a 3
slot ISA bus. Most of the system ran at native 32 bit, so you just ran
a slow network card in the ISA. They also had up to 32mb memory, and an
optional memory cache card to speed things up.
The systems had issues, both on-board batteries were dead, resulting in
me having to find, download, run (not easy) and extract a setup floppy
for this model as you can't do the system settings without it. Not quite
an EISA config, but similar levels of stupidity in the ISA world. And
one of them does not seem to see the ISA bus, but not a big deal as it
will just be a DOS floppy maker.
Anyway, finally got one of them running and decided to do some
benchmarks. Booting NextStep 4.2, and tried out a few basic tests.
Findings:
For general booting and such the Pentium does not offer that much of an
advantage. Time to go from login window to system quiet with 20mb memory
(I load several apps by default) is:
486/100-121 seconds
Pentium: 120 seconds
Installing and removing the 256k cache card (an option I have one of)
doesn't change the time much at all, maybe a second.
Boosting memory to 32mb brought that number down to 84 seconds. Moral:
Memory matters.
Then I figured I would try a CPU intensive app: Good old NeXT
Mandelbrot. While a true NeXT slab will kick the rear of any Intel chip
(due to the on board DSP56001) I figured I would put the Pentium up
against the 486/100 and running the 486 at 33mhz external bus (133mhz)
in insane overclock mode.`So rendering the "Valley of Fear" (a complex
subset) resulted in:
Pentium, no external cache: 36 seconds.
Pentium, external cache: 34 seconds.
Not bad, cache really doesn't do a whole lot here.
486/100, no cache: 90 seconds. Wow, that is slow.
486/133, no cache: 65s. Faster, but very slow.
So the addition of the Pentium makes a huge difference on floating point
CPU intensive apps. I'm also guessing the extra large cache makes a
difference as well for highly iterative loads.
With this done I can continue looking for a 5.25 floppy to see about
making more PRO disks.
Hi,
Has anyone seen the latest on ArsTECHNICA journal on Brian Green’s
“deluxe home vintage computer den”? Does it bring back many fond memories
of the 70s and 80s. 🙂
Happy computing.
Murray 🙂
I attended the Vintage Computer Faire at the Computer History Museum many a
yr. ago. The museum wasn't opened yet then collecting many computer
artifacts including the Cray-1. I also met Steve Wozniak who gladdened the
heart of this Canadian nerd/geek/computer enthusiast. I'm looking forward
to visiting the museum again in the not-too-distant future. There are
computer museums here in Canada; one has Kenbak-1s.
The latest issue of Mad Magazine (April 2023) is titled “MAD Takes Apart Technology”. The pages include reprints of past articles that relate to computers, such as “if computers are so brilliant” (Oct 1985), “13 things you never want to hear from a computer guy” (May 2005), various y2k, and some 50s/60s tech humor. I posted the cover photo here: https://ne.thote.it/@tarek/110018157647679272
Regards,
Tarek Hoteit
Oh yes, that's looking good :-)
Thank you very much Mattis!
BTW: Some years before I helped to repair and administering the east
german copy of an 11/780.. the Robotron RVS K1840.
The console Processor of this beast was an Robotron K1620, the slowest
PDP-11 ever made but it was enough to load the microcode :-)
The 1620 used two 5,25" Floppies instead of the 8" one in the 11/780.
Best regards,
Holm
Mattis Lind wrote:
> That is a BA11-M box with a H780 supply. The schematics can be found in the
> KC780 document since the front end processor of the 11/780 is a PDP-11/03
> with a RX01 drive.
> In the end of this document there is a schematic:
>
> http://bitsavers.org/pdf/dec/vax/780/MP00534_KC780_Nov77.pdf
>
> Good luck!
>
> /Mattis
>
> Den mån 13 mars 2023 kl 10:57 skrev Holm Tiffe via cctalk <
> cctalk(a)classiccmp.org>:
>
> >
> > Hi all,
> >
> > I have to repair an PSU of a 11/23 n a BA11 Box with an H9720 Backplane
> > (with an KDJ-11A) that has run an CNC milling machine until 2 weeks
> > before now. :-) This is a Fidia machine..never heard about it before.
> >
> > The problem is that a big 19000µF 40V capacitor in the PSU has failed
> > and that I think because of that the 2nd of the two Nidec fans has
> > finally failed.
> > I'm in the process of cleaning the goo from the PSU-PCB, found a burnt
> > 5A fuse and now I'm checking the Semiconductors...
> >
> > The problem is here that the Transistors (and diodes) have uncommon
> > types printed on, an TO220 is named SJE2677, another one is labeled
> > 12652-00 RCA..and so on.
> > I've found a label with "0H780-B" on the PSU.. H780 PSU?
> > Where can I get some schematics from that beast? It is a secondary
> > switcher ist seems.
> >
> > Regards,
> > Holm
> > --
> > Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe,
> > Goethestrasse 15, 09569 Oederan, USt-Id: DE253710583
> > info(a)tsht.de Fax +49 37292 709779 Tel +49 37292 709778 Mobil: 0172 8790
> > 741
> >
> >
--
Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe,
Goethestrasse 15, 09569 Oederan, USt-Id: DE253710583
info(a)tsht.de Fax +49 37292 709779 Tel +49 37292 709778 Mobil: 0172 8790 741
----- Ende weitergeleitete Nachricht -----
--
Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe,
Goethestrasse 15, 09569 Oederan, USt-Id: DE253710583
info(a)tsht.de Fax +49 37292 709779 Tel +49 37292 709778 Mobil: 0172 8790 741
I’m working on a project, and I need to know the age of various tape formats. For example when were 6250bpi 700’ 9-Track tapes or DC600A cartridges introduced? Is there any good resource online that documents this? Wikipedia is of some help, but the older you go, the spottier it is.
Zane
Anyone here have a physical copy of 80 Microcomputing (TRS-80 themed) issue
from August 1980? There is a better quality scan of a page I'm trying to
get.
Thanks,
Steve
