Can anybody here help this guy out?
---------- Forwarded Message ----------
Subject: [sdiy] Wanted: Multibus (late 70s microprocessor bus) extender card
Date: Tuesday 31 July 2007 17:30
From: "Steve Lenham" <lenham at clara.co.uk>
To: "SDIY list" <synth-diy at dropmix.xs4all.nl>
Does anyone happen to have spare, or can anyone point me in the direction of
an inexpensive source for, an extender card for Multibus (the late 70s
microprocessor bus standard)? I know that Digikey and Mouser list them new,
but they are around $120 each.
I'm working on a Lexicon 224 reverb unit (a fascinating device), which uses
a Multibus backplane and eight plug-in cards. I need to be able to work on
these cards with them still attached to the bus - hence the need for an
Any pointers would be much appreciated. I'm in the UK, but am happy to
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Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
Information is more dangerous than cannon to a society ruled by lies. --James
At 18:38 01-Aug, Jerry wrote:
>I'm trying to get a MONO Cube I have here back to
>a complete box.
>Missing is the
>- Floppy Drive 2.88 Sony and Bezel
Drive is not so critical, many of them didn't have that. But having
one is pretty nice when it comes time to boot the install CD. A Bezel
is a *big* deal because of cooling airflow, I found out. My floppy
drive looks out through a non-bezel aperture, which I keep covered
with tape most of the time so cooling air doesn't escape that way.
>- mounting Bracket for the Drives ??? The large piece
> above the Power Supply is there. I would guess it had
> something to hold the 3 1/2 drives.
The what? ;-) NeXT supplied 5.25" hard drives, which just fit between
the walls and mount with bolts through the bolt-holes in the side
walls. You are more or less on your own for mounting a 3.5" drive in
a cube. Mine
>- no Optical drive or cover. Not Sure it had one ??
Many of them didn't have an optical drive, and almost *none* of them
now have a functioning optical. Dust is one culprit, but there seems
to be something (I have not really investigated) that kills them all
over time. The optical is a great novelty and I really wish it had
caught on, but it's not too useful today.
>- no expansion slot covers. Rear cover is there.
I think these would be less critical for cooling, but still good to have.
>- mouse is missing
Depending on the model, you may be able to use an ADB mouse (though
will miss the other button). Do you have an ADB keyboard
(distinguished by the "control" bar below the space bar)?
>This is a 68040 25 built is 1991
>Looking into the 2.88 floppy it looks like there was
>no standard for the connection on the different makes.
>So either I have to use a sony or make a adapter
Sony, I think. I'm not aware of any substitutes.
I can endorse Randy Rencsok, reachable through:
as a parts supplier. There are also a fair number of downloads on his
site which may be of use to you, as well as pictures of some of the
I also note the existence of
but have not done business with Rob Blessin, though he's been pretty
supportive in general of the NeXT community.
- Mark, 210-379-4635
Large Asteroids headed toward planets
inhabited by beings that don't have
technology adequate to stop them:
Think of it as Evolution in Fast-Forward.
I'd be delighted to attend a UK VCF if there was one
or something similar.
At a push I would be happy to demo a few
interesting machines :)
Boardwalk for $500? In 2007? Ha! Play Monopoly Here and Now (it's updated for today's economy) at Yahoo! Games.
I'd be interested too.
For venues, what kind of size place would be
needed? I've vistited several fairly active
shows, some of which could be called somewhat
vintage - eg the RiscOS shows. These are often
held in sports halls or similar. There is also
the retro show North, which is more classic
gaming consoles. (www.retronorth.co.uk)
Some others in the past included the 'all formats
computer fairs', which often combined commercial
sellers/items for sale with stands from clubs. A
bit like the VCF in Mountain View.
Pinpoint customers who are looking for what you sell.
>Subject: Re: Imagedisk 1.17
> From: "Dave Dunfield" <dave06a at dunfield.com>
> Date: Fri, 27 Jul 2007 07:11:40 -0500
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>> Lately I've found a very nasty bugs in IMD 1.16 (at least with a secondary
>> FDC, tested on two different machines of different speed with different
>> FDC). Reading disks is mostly fine, but writing to a drive connected to a
>> secondary FDC doesn't work reliably. The problem is that the drive won't
>> step properly, i.e. sometimes it misses a step pulse which makes the
>> written disk unusable. The same problem occurs e.g. with the clean head
>> routine. I had a look on your source code and I think it's a timing
>> issue. I've inserted a small delay ('delay(55);') into the seek routine
>> (between line 998 and line 999 in version 1.16) and this solved all the
>> problem. I think that the seek routine is called too early after having
>> sent the previous command to the FDC although it shouldn't matter because
>> wrfdc officially waits for the FDC to be ready before sending a byte. But
>> apparently some (many? all?) FDCs appear to be in a ready state although
>> they are not yet ready to do a seek... really weird.
>It's impossible to test every FDC (at least in a free project). This
>explaination doesn't make sense because the seek routine has a 55ms settleing
>delay at the end (which you can increase with the SD= option), and the clean-
>head routine has a 100ms delay between seeks, which makes a total of 150ms
>delay. There are no other intervening commands during "clean heads" - since
>seek() waits for seek complete, 150ms should be plenty of time for the
>controller to be ready for another command. This also does not explain why
>reading a disk would work, so I suspect there is some other factor involved
>This is the first I've heard of this problem - if you have problems with
>ImageDisk, the best way to get it fixed correctly might be to work with
>me on it instead of posting "fixes" to public forums. But... thats what
>happens when you release source code.
Ah, the step gremlin. It's an old 765(all!!!) problem. The problem is when
the step pulse is set to minimum acceptable for the drive it's possible that
due to internal timing of the 765 it can shorten the step timing of the
first pulse by 1 count. If that occurs many drives seek badly and you get
read or write errors because your not where you thought you were.
Note: some old drives due to the lubricants turning to goo will also exhibit
this type of error. There is one solution, step slower (SRT+1).
Another problem is the 765 was designed for 77track drives (8" floppy)
and there were no 80track minifloppies. So the Recal only issued
77 step pulses and would flag an see error if the drive was 80track.
One fix is to issue a new Recal and see if the drive properly homed
this time. The problem is there are some cores that fixed this and will
issue up to 256 step pulses. The problem can also arise when using
SA400/400L style drives ans some (not all) will jump track (loose
the groove on the positioner disk) if stepped too far past tracks
000 or 39.
Last gremlin is the 765(and cores) were designed to Seek/Recal up to 4
drives but PC hardware does not always decode this and may have drive 0
also appearing as drive 2 or 3 which makes it susceptable to being
repositioned by commands not intended for it.
> No matter what language, toggling in your code teaches (or
>scares) you to write efficient code. : )
LOL, I used to seriously mess with my boss' head when dubugging code.
I used to patch my code, in hex, in an EPROM emulator (a "Softy S3") as it
was quicker than editing the source on my PC, assembling it and then
downloading it the the emulator....
He just couldn't get his head around how I could "assemble" code in my head,
even when I explained to him how easy it was when you understood how the
opcodes were formed (doesn't work for all processors mind).
TTFN - Pete.
Just to add some clarity here:
1) No, "Vintage Computer Festival" is not trademarked internationally, nor
do I have any inclination to invest the enormous amounts of money to do
so. Besides, if anyone did want to try to put on a vintage computer
festival and call it the "Vintage Computer Festival", there's a simple
solution to that: I would hold a real Vintage Computer Festival down the
street from theirs on the same dates and advertise the hell out of it and
ensure that the wannabe "VCF" only got two attendees (who would be
stragglers from the real VCF up the way ;)
2) There have been several discussions over the years about hosting a VCF
UK. I can say it WILL happen--at some point. I just need someone in the
UK eager and ready to make it happen. Talk to Evan or Pat about their
experiences to see how it is done. Of course, talk to me if you're
seriously interested and I'll get you started. It would be nice to
finally have a VCF UK starting in 2008.
3) I am always interested in expanding the VCF to any area on Earth where
there is a viable chance of it succeeding (i.e. attracting more than a
few dozen attendees). I would really like to expand into Japan and South
America, but I will consider any location (that doesn't conflict with
This year is the 10th anniversary of the VCF (it's now on topic!) If
you've never been to the main VCF in the Sillycon Valley, this is the year
to come. The dates are November 3-4 (and don't be surprised if they are
extended). Now that it's August, planning will begin in earnest.
Speakers will start getting posted soon. Now is a great time to start
thinking about an exhibit and getting it registered.
A bunch of exciting announcements are in the works so stay tuned ;)
Sellam Ismail Vintage Computer Festival
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
That isn't the point, Pete. The point is: everyone knows the VCF is Sellam's thing and it would be really lame for someone else to make an event and call it a VCF. It would also just be dumb even if it weren't unethical: Sellam (and me and Hans and Pat) have done around 20 VCFs so far and we learned a LOT from the experience, so whoever is serious about making a new VCF would be wise to work with Sellam's organization, not around or against it.
I just collected a Victor machine which I believe to be the 9000 aka
Sirius 1, although it does not have a model # anywhere I can find.
The fans and drive powers up, but the display does not. It appears to
get its power via the 9-pin signal cable. Can anyone confirm that
this is the case and if this is a common issue, perhaps with an
equally common fix?
Retrocomputing and collecting in the Chicago area:
I am attempting to revive a Vax-11/750 that I recently acquired. During the several moves of the machine, damage was done to the 875-A power controller. The fuse holder, power control switch, and circuit breaker were all damaged.
In particular, the circuit breaker (CB1) had the handles snapped clean off. The individual poles can be moved to the ON position, but always return to the OFF position.
I am looking for a replacement of either the entire power controller, or, just the circuit breaker assembly.
I have located a for-profit source of an 875-A, but it will be a few hundred dollars to purchase it.
If anyone has a spare 875-A or breaker, I would be extremely grateful.