Hi! Remember the blearrnnnnt-meeeeeelrp sounding seek oscillation noise
that the RD54 makes when you turn it on -- after it spins up, unlatches and
loads the heads?
Well, I took a chance on an el-(c)heapo ePay special RD54 that does all
these things perfectly up until the seek oscillation thing and then only
makes one steady meeee- sound that seems to last indefinitely (or at least
until I get tired of listening to it after a few minutes).
Would anyone here know enough about these disks to venture a guess at where
to begin troubleshooting this?
thx
jake
P.S. If I'm being too vague, let me restate: I can hear it spin up,
bearings sound normal, hear it unlock its head lock latch, then a perfectly
*slight* noise of head actuation and the normal accompanying barely audible
riding-on-air head noise. Then I expect to hear the two seek tones, but
only get one steady seek tone that lasts (I assume) forever.
I have a Visual 50 terminal that I am now troubleshooting. I got it in the
late 1980s and it worked fine until 1995. I can't find a good schematic for
it or ROM images. Its symptom is that it powers up to continual beep (solid
tone, not repeated beeps) with a cursor on the screen. This is not in the
troubleshooting table of the manual that I have.
I know the keyboard is capacitive foam pads. I was hoping that was the
trouble, but it is not. I disassembled the keyboard and removed the old
pads, replacing a few with some spares I had from SOL20 repairs.
Has anyone corrected this problem before? I suspect that the EPROMs are
going.
Thanks,
Bill Sudbrink
--
This email has been checked for viruses by Avast antivirus software.
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> Googling for "mirror uxc.cso.uiuc.edu" found me one hopeful hit:
> https://www.funet.fi > pub > misc > Notes.README
Ron,
Another good search approach that I hadn't thought of. Many thanks!
De
Does anyone have or know of an archive of old mod.sources (predecessor
of comp.sources.unix) posts? I know googlegroups has it, but that only
means nothing since it's effectively inaccessible there.
De
Hi all,
I recently acquired a very nice decwriter III and it seems in good nick. However, the self test "hangs" on the return direction of the second line. Here is a video on it:
https://youtu.be/pj6rk5Dlnbk
Anyone have any ideas where to look? In local mode, it appears to work properly. I haven't tried any external serial connection yet.
73 Eugene W2HX
My Youtube Channel: https://www.youtube.com/@w2hx/videos
Fellow nerds,
not sure who knows about this project, so here an announcement ... again?
As QBUS PDP-11s (03,23,73,83,93, also uVAX) don't have lots of
lamps&switches
like the old UNIBUS machines, their owners suffer on "Blinkenlight envy".
So I was pushed to pimp up the QBUS diagnostic adapter "QProbe"
https://www.retrocmp.com/tools/qprobe
Model "QProbe2023" has now focus on entertainment.
There's a QBUS signal display in style of old PDP-10/12/15 rack header
panels.
It can be build into a 5.25" drive case ... or into the BA23 case itself.
https://www.retrocmp.com/tools/qprobe/327-qprobe2023-overview
By lucky incident you can even see the idle loop pattern of RSX11M+ on some
J11 systems. See a full boot of RSX11M+ at time index 5:56 of
https://www.youtube.com/watch?v=ajAcxGwK-vQ
As it also has RESTART/HALT/AUX switches, it's also helpful for PDP-11s
mounted
case-less in a standalone backplane (like the one at
https://retrocmp.com/projects/lsibox and on the "Frankenstein" video
https://www.youtube.com/watch?v=hoW7Szkppww&t=403s )
Btw for unknown reasons, I cannot register to classiccmp itself ... CC
me direct in your replies.
kind regards,
Joerg
Hi Jon!
> think the Bendix G-15 had cassettes for the 5-level tape
> they used.
Aha, interesting! Did a short search, but have not been able to
find a picture of a casette. Just a pile of paper tape instead ;-)
https://images.app.goo.gl/HYqkpYHJUxZeGfiA8
> of mylar tape instead of paper. OS boot tapes might be punched
> on that.
Yes, for heavy use (and e.g. humid environments), the mil guys obviously
used Mylar or heavily oiled tape. Although not experrienced myself, I was
told that the Mylar tape cuts through the guiding pins of the readers over
time. And yes, it also may easily cut one's fingers ;-)
> much like plain paper tape, and simple mylar alone. The latter often
> comes metallized on one side, and is glossy.
Yes, that is the one within the casette and the aluminum as you expect
is for optical reading (Most plastics including Mylar are quite
transparent for IR light and in the old days, when thungsten bulbs
where used, the IR part of the light was the major part contributing
to the response of the photodiodes!
> input medium for the university mainframe computer (Electrologica X8),
> they used optical readers rated at 2000 characters per second.
Wow - that is indeed pretty fast!!! My FACIT is 1200cps maximum and
stopping "on character" as it is called is VERY hard at that speed.
But buffering helps here and in case of the 920M, the casette is
used for, there was no buffering. So software needs to be read in
one run.
Best wishes,
Erik.
''~``
( o o )
+--------------------------.oooO--(_)--Oooo.-------------------------+
| Dr. Erik Baigar Inertial Navigation & |
| Salzstrasse 1 .oooO Vintage Computer |
| D87616 Marktoberdorf ( ) Oooo. Hobbyist / Physicist |
| erik(a)baigar.de +------\ (----( )---------------------------+
| www.baigar.de | \_) ) /
+----------------------+ (_/
Hi Paul,
thanks for your answer and the interesting links...
> > Aha, interesting! Did a short search, but have not been able to
> > find a picture of a casette. Just a pile of paper tape instead ;-)
> >
> > https://images.app.goo.gl/HYqkpYHJUxZeGfiA8
>
> Bitsavers has a collection of G-15 manuals. For a picture of an
> open cassette, see PDF page 27 in http://bitsavers.org/pdf/bendix/g-15/60061400_G15D_Parts_Manual.pdf.
Ahh OK, I see. But that is not a hermetically sealed casette
suitable for outdoor use in windy, rainy weather like the
one on my desk.
As the thread deviated meanwhile, I guess the Elliott Mylar
tape casette is a unique leftover from the old days ;-)
Best wishes,
Erik.
''~``
( o o )
+--------------------------.oooO--(_)--Oooo.-------------------------+
| Dr. Erik Baigar Inertial Navigation & |
| Salzstrasse 1 .oooO Vintage Computer |
| D87616 Marktoberdorf ( ) Oooo. Hobbyist / Physicist |
| erik(a)baigar.de +------\ (----( )---------------------------+
| www.baigar.de | \_) ) /
+----------------------+ (_/
Hi there - recently I posted a small video on a rugged
paper tape casette...
https://www.youtube.com/watch?v=O2jnThYsPKc
I wonder whether anyone kows if someone else had the idea
of putting paper/mylar tape into a casette for repeated use
e.g. to load an OS or similar.
Best wishes,
Erik.
''~``
( o o )
+------------------------.oooO--(_)--Oooo.---------------------------+
| Dr. Erik Baigar Inertial Navigation & |
| Salzstrasse 1 .oooO Vintage Computer |
| D87616 Marktoberdorf ( ) Oooo. Hobbyist / Physicist |
| erik(a)baigar.de +----\ (----( )-----------------------------+
| www.baigar.de | \_) ) /
+----------------------+ (_/
I have some 8-bit ISA 53c90a based SCSI controllers labeled "SCSI HB A8".
Mine are made by "Advanced Information Concepts", but apparently they were
also made by "Control Concepts". Unfortunately, mine don't have the BIOS
chips installed. I have a picture of the card with a chip installed
labeled "Ver-3.02 CCI 0991", so I know an 8k or 16k boot prom existed.
Does anyone have such a card that they'd be willing to dump a prom image
from (or let me borrow it to dump).
KJ
