Quick one:
Anybody has softcopy manual of BDV11? Or at least notes on jumper configs...
Looked at all the usual places, but didn't come up with anything...
/wai-sun
Right. It's *not* the 8530 SCC chip that's faulty, but it's *not* the
data bus either - there's plenty of bus activity so bit 6 isn't
permanently jammed high.
After checking the bus, I replaced the SCC chip with a socket and tried
my spare SCC chip from home (remarkably easy job as it turned out) -
gave exactly the same results on the console.
So, it looks like bit 6 of the bus is fine *except* when a serial port
access is in progress (i.e. other things sharing that bus are being
accessed fine)
Three possibilities at the moment:
1) The big LSI Logic L1A3626 IC which appears to control the serial port
bus is broken internally.
2) Something upstream of the LSI Logic chip is faulty.
3) Something else on the board is responsible for driving the bus during
SCC ops, and there's a break in the bit 6 track to it somewhere,
resulting in it always floating high during serial access.
I can't do much about 1 and 2 without knowing the pinouts of the LSI
chip or having full schematics of the board :-(
Point 3 I can test by tracing one of the other data bus lines and seeing
if it goes anywhere that line #6 doesn't.
I had a look at our Sparc 1 and 2 machines, but they don't use the same
chipset. They do however have a similar IC to the LSI chip in the 4/330
marked as "buffer" which of course increases suspicion that the LSI chip
in the 4/330 - or something upstream of it - has broken.
Chances are I'll be looking for a new board (yeah, right!) given the
lack of schematics. Other alternative would be to find a framebuffer
board for the machine and then use a graphical console - it might be
easier to find a compatible framebuffer versus a whole new 4/330
board...
Grumble!
cheers
Jules
Hi folks,
I've just stumbled on this - looks like someone's built a full CPU board
out of TTL. Wire-wrapped it too (I'm surprised it works - I never had much
luck with wire-wrap). I haven't had chance to take a good look at it, but
what I've seen is pretty interesting.
Link:
<http://www.homebuiltcpu.com/>
Later,
--
Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
philpem at philpem.me.uk | ViewFinder, 10BaseT Ethernet, 2-slice,
http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI
... All you folks do not exist. My sysop types all this stuff in.
Last week, in the middle of debugging Kermit (and making headway)
the 6070 disk dropped dead (I think the technical word for it is
'sh*t the bed').
I was operating it remotely (ssh to host machine w/minicom) so I
couldn't see that the power-OK led went out. Unloaded the heads,
powered off, checked for massive damage, etc, powered on, no POWER
OK or LOAD. Off for the night.
Next day, powered on OK, (power OK led on), LOAD, READY (headload
OK) but can't boot; the bootstrap always seems to get wiped out
whne the machine shutsdown badly. Can't write bootstrap (from
tape).
Diags failed; long story short, all of the disk logic seems good,
media is fine (whew!), seek and format, but no read-data at all --
can't read sector address headers post-format.
All four surfaces the same, so it's not heads or stuff up to the
input mux, diags seem to think it's likely in the disk drive.
I hope to put the 'scope on it tomorrow and begind debug. The
power-OK failure bugs me, though if some driver was able to drag a
power supply out of spec for many minutes you'd think there would
be evidence of, let's say, excessive power consumption (aka
smoke'n'flames). This ain't CMOS.
We'll see. Lost a bit of work, but everything was backup onto
tapes (multiple tape files each tape, plus multiple tapes).
Can't wait til Kermit is running!
Michael Sokolov wrote:
> I have previously heard of people connecting TK50 drives to TK70
> controllers. Supposedly it results in better performance. I don't know
> if you lose the ability to write TK50 tapes this way or not.
>
> This is the first time I hear about the opposite combination, but I have
> to assume it works - whoever put it together obviously had it working,
> otherwise the combo you have in your hands would not exist. MS
Er - couldn't it? It was junked, and nobody had bothered to make the cover
fit again. So it might just have been a try (say the original TK50 was dead)
to install a TK70, which didn't work and was subsequently abandoned. On the
other hand,
Fred N. van Kempen wrote:
> The TZK50 controller (which converts TKbus to SCSI) works with
> both units. The TK70 is smart enough to "fall back" to the
> slower TK50 data mode, so it'll just act like a faster (and
> somewhat more reliable) TK50 drive.
So it should work (and opinions differ whether the TK50 or the TK70 is more
reliable); the case front is the only issue. I see three possibilities:
-Running the thing without case (possibly bad idea, the resistor board in
the upper left seems to need constant directed air flow) or just without
front panel (ugly, things can get in)
-Widening the front panel cutout enough to accomodate the TK70 panel, or
trimming the transport's front bezel enough to fit in the hole (requires
irreversible modifications on original parts, so perhaps bad idea; however,
it looks doable without major damage)
-producing a new case front with a bigger opening (time for some
wood-carving?)
But, as I don't need it now, there is still the alternative of waiting for a
TK50 transport to fall from heaven. The TK70 could be removed from the
enclosure and used to (at least temporarily) substitute the TK50 which is
missing in our MicroVAX II (BA123 housing) in the university museum. Its
frontpanel has an opening which is big enough, curiously. (I had it home
over the weekend to repair the door hinge, st*p*d plastic pin had broken
off, hole was drilled in and a metal bolt inserted instead).
--
Arno Kletzander
Stud. Hilfskraft Informatik Sammlung Erlangen
www.iser.uni-erlangen.de
Handyrechnung zu hoch? Tipp: SMS und MMS mit GMX
Seien Sie so frei: Alle Infos unter http://www.gmx.net/de/go/freesms
I recently saw a poster for http://www.freecycle.org/ .
"It's a grassroots movement of people who are giving (& getting)
stuff for free in their own towns. Each local group is run by
a local volunteer moderator. Membership is free."
I signed up a few weeks ago. Today I got a carload of old Commodore,
Atari, Tandy and Mac IIci-era junk, free for the hauling ten minutes
away, but I had to "take it all".
It made me think there might be a business opportunity in a
"freeBay.com" style site - like eBay but without the cost.
And indeed, a little googling revealed other sites with the
same aim.
If anything, I think Freecycle suffers from a lack of centralized
interface. Not everyone is smart enough to sign up for a mailing list,
and a web interface would be easier to search. (Oops, didn't mean to
start that "list vs. web" thread again. I give up. You're right,
yes, absolutely, eBay should be a mailing list and not a web site.)
I might want to subscribe to my county's list, but I'd also drive three
hours for the right giveaway. It also made me think there could be
opportunity in aggregating and searching these giveaway mailing lists.
It would be great to filter the messages that contain the word "computer"
or "fish tank" or whatever you're hunting for. At a simple level,
you could do it with your mail-reader's filters.
"freeBay.com" is in some sort of registrar-lock. Like the "hot deal"
sites, an operator could make money on keywords and affiliate ads.
- John
While looking for something else in old magazines I ran across a
series of articles by Edmund C. Berkeley and Robert A. Jensen on the design
and construction of the Simon relay computer. (Oct 1950 to Sept 1951 Radio
Electronics) I can't find number 13 in Oct 1951, which is apparently a
description
of a different computer.
Would it be worthwhile trying to scan these and try to get someone
to post them?
Regards
Charlie Fox
Charles E. Fox Video Production
793 Argyle Rd.
Windsor Ontario Canada N8Y 3J8
519-254-4991 cfox1 at cogeco.ca
Check out The Camcorder Kindergarten
at www.chasfoxvideo.com
Dan wrote:
> Note that the name of the picture file is foo.jpeg
> but who knows.
Sure -- I realize that.
What I was referring to though was that:
http://www.geocities.com/heftyharry/foo.jpg
looks as if it is a photoshopped version of the 'real' picture at:
http://ed-thelen.org/comp-hist/BRL61-bendix-g15d.jpg.
Besides, heftyharry's G-15 doesn't look quite deep enough to actually hold
all the guts of the computer. Cropping it off towards the back end, and
placing some debris in back of it, is what gave it away.
I think I'll just take my medicine here, and admit to the fact that I've
been duped by an April 1st shenanigan. :-P
--- Heinz Wolter <h.wolter at sympatico.ca> wrote:
> that's a pdp1 front panel and tty, no? ;) april
> fools?
> h
Yes it is a PDP-1. But it is well-documented that
the major customer for the PDP-1 was ITT, who used it
for a teleprinter switching application. This
does look like an April Fool's joke, however.
That console typewriter looks too clean. Even
more suspicious is that the console typewriter is
sitting next to what appears to be the graphics
scope. There are several pictures on the net of
PDP-1s in museum exhibits that look like this, but
in all the old photos, it looks like the typewriter
was likely to be on a table attached to the CPU
cabinet. It is also dubious that the teletype
switch application would use a graphics scope at all.
Also, the picture of the internals shows a machine
in a non-standard white cabinet that strongly
resembles
the prototype PDP-1 at the CHM. The whole thing
smells fake, but I sent the guy a serious response
anyway indicating the value of the find.
--Bill
>From: "Marvin Johnston" <marvin at rain.org>
>
>
>In searching for radio gear, I ran across this URL and thought it might
>of some interest here. I don't recognize it, but it looks like it might
>be some older computer stuff.
>
>http://www.geocities.com/heftyharry/OLD_COMPUTER_SALE.html
>
Hi
It might be an analog computer but it looks more
like a power monitor for a large computer.
He didn't have an address?
Dwight
