Hi all!
I'm working on a little side project to see why one can't put a better
CPU chip into a Sun 386i. Basically with a real 386 in the socket the
system will at least start to flash the LEDs on the back, but with a
Cyrix chip the LEDs are frozen on.
I can remove the frame buffer, memory cards, even the Timekeeper chip
and I still see this behavior. Running with no CPU or no PROM chip makes
the system flash no lights, pointing to the problem being code in the PROM.
Now, 386 CPUs don't have the CPUID register, but they do have a little
feature where upon reset EDX contains a "3" to show the CPU "type". On a
Cyrix chip it contains a "4".
My guess is the ROM code has at the beginning a check of EDX and if <>3
go to a halt. I'd like to dump the code, find that check, and either
replace the 3 with a 4, or replace the first HALT with a NOOP.
The PROM is an Intel D27010 which is an Intel 128k*8 chip. Unfortunately
I'm not finding much in terms of either datasheets or PROM programmers.
Does anyone know how to/have the tools to dump and reprogram this? I'll
bet the old archives that talk about the "Blue Lightning 386" working
for boot were due to the chip being made under license of Intel thus
being allowed to have that "3" in there.
But since I also have a TI 386/486 chip with 8k of L1 cache, a 486 core
instruction set, faster multiplier, and clock doubling by default I
think it might wind up being.... faster.
C
Does anyone have interest in vintage diskette duplication / duplication
machines? Would this make for an interesting VCF exhibit? Does/did anyone
use these commercially?
Bill
Just a ping out there to see if anyone's sitting on installation media for
CommonPoint (the last gasp of Taligent). Seems appropriate to try to coerce it
to run on an Apple Network Server. Let me know on or off list as appropriate.
--
------------------------------------ personal: http://www.cameronkaiser.com/ --
Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser(a)floodgap.com
-- "I'd love to go out with you, but I need to clean my toilet brush." --------
Over the years, I have gradually built up a functional PDP-11/23+
system, which of course I now have no need for ;) So I'd be interested
in selling it as I slowly downsize. You'd need to pick it up in south
central Missouri as shipping would be impractical and expensive.
Specifics: 11/23+ with 4MB RAM, selectable boot ROMs, two RL02 drives,
floppy interface (set to 3.5" TEAC drive), 16-line serial ports,
corporate cabinet with DEC power controller. Software including RT-11SJ,
XM, TSX-Plus. Also have a VT-220 for the console which I may sell
separately or with the system.
Please email me *off-list* with offers, request for pics, etc.
thanks
Charles
I look back fondly on the IBM PC-XT of 41 years ago. It was very pricy here
in the Great North but it allowed for a much more advanced computing
environment. What one could do with a 10MB hard disk! Granted it was far
more popular in the business world than the consumer one. However, it made
possible much greater developments that hobbyists and experimenters latched
onto.
Happy computing!
Murray 😊
Hello classic computing fans! The new website for VCF Midwest is up at
https://vcfmw.org. Who knows the design inspiration without asking a
(Commodore) friend?? Apologies if it doesn't render well on your device.
I don't have your device!
Room booking for the show will open this afternoon (Friday 3/8). It will
be announced via the mailing list and a refresh of this web page (at the
"HOTEL" link.)
Lots more rooms this time, and we're starting with an empty block. But
it's still best to book early if you want to stay at the show hotel!
See you in September...
-jt
I'm gathering photos of Lisp machines (of all makes and models). If
you've got them scanned already, that's great, otherwise I have a
scanner if you're willing to entrust your photos to me temporarily.
Let's take replies off-list unless you think it'll be of general
interest to subscribers.
Thanks,
John
I hope a 1974 desk calculator (Radio Shack EC-2000, a re-badged TI-3500)
is considered sufficiently both classic and computer for this list. :)
The one IC, a TI TMS0106NC, has failed and I'm searching everywhere for
a replacement. There's an -0103 on ebay from the same family which would
substitute, but it's only 8 digits and this is a 10 digit machine. Plus
it's $31 with postage, more than the calculator itself is worth!
If anyone has one, or knows where I can get this IC, new or a pull,
please let me know.
Thanks!
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
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