I have these two external drive cases, once called "Leprechaun boxes";
one held an external RD52 and one held an external TK50 - same enclosure,
same PSU, different cable transition header at the back.
The problem is that every one of these that I've ever seen has had the
PSU die. One of these was repaired by my order (with company funds!)
about 15 years ago by ESS. I don't fancy a professional replacement
at this stage.
I do not have schematics. I do not not understand switching PSUs
well enough to do more than take stabs. I know they involve high
voltage, high-frequency oscillations, but that doesn't help me fix
them. :-( Is anyone on the list familiar with these enough to
suggest common failure modes?
If the case were a wee bit taller and wider, I'd consider putting
a commodity PSU in the cage. Don't think there's room for one in
there, though. Not desktop sized, anyway. Anyone have ratings for
the Leprechaun box? Looks like .45A @ 125V from the back, which tells
me that it's not a strong PSU (~60W max draw, so probably no more than
40-50W pull, I'd guess). I wish I'd bought more of these $5 tiny
cases at Dayton a couple of years ago - the PSUs will fit into your
palm and provide at least that much current (enough to drive a small
PeeCee motherboard and a 3.5" drive).
Thanks for any assistance.
-ethan
__________________________________________________
Do You Yahoo!?
Yahoo! - Official partner of 2002 FIFA World Cup
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I run a set of searches on ebay just about daily.
One of the searches is for IMSAI. This morning,
for the first time in about two years, a search
for IMSAI resulted in no hits. I found this interesting.
Thought others might as well.
Hi
I have a machine with a Z8000 that is working.
It is the Olivetti M20. You should be able to find these
in Europe. They were many sold in Italy and Germany.
It uses a OS made by Olivetti called PCOS. There are
a few 32032's around. I also have a couple of the
National modules ( I think they were called RA2000 )
that have the NSC800 processor in them ( similar to the Z80 ).
These were designed to stack and have a Forth built in.
There was a module made by Fairchild that has a RISC processor
on it that I have someplace as well. I'm not sure if this
one ever made it to production. I think I even have some
manuals for it as well.
Not many of the 432's made it out of Intel. I'm not surprised
that these are rare. There was also a Z80000 someplace as I recall.
I guess there are a lot of holes in your collection :-(
Dwight
On Wed, 12 Jun 2002, John Honniball wrote:
>
> All this mention of Motorola's 88000 RISC chip has made me wonder
> what machines were built around it. Did Data General make anything
> with it? Was there a Motorola development system?
>
> One of my collecting goals is to acquire an example of each of
> the microprocessor acrhitectures. Now 6502, 8080, 6809, 68000,
> and so on are easy. What about the Z8000? The 32032 (I do have
> a Whitechapel)? The 88000? The iAPX432?
>
> --
> John Honniball
> coredump(a)gifford.co.uk
>
>From: ard(a)p850ug1.demon.co.uk
>> >
>> > Just a sanity check, here. What would be the _DC_ rating of a
>> > momentary switch rated at 3A, 125VAC?
>> >
>> > Doc
>>
>> About 175 volts. Most 1 farad caps are rated at 5.5 volts.
>
>Never!. A DC arc is much harder to extinguish than an AC arc (the
>simplistic explanation is that the AC voltage drops to 0 twice per cycle,
>thus helping to extinguish the arc). The DC rating of a mechanical switch
>is not sqrt(2) times the AC rating.
>
>It's a lot less. I would not want to use that swtich _for resistive
>loads_ at more than about 24 volts. For significantly inductive loads it
>would be even less than that.
>
>When I was at university there was a physics experiment involving a large
>solenoid coil powered from a 24V 10A (or so) bench PSU. The switch was
>one of those old knife swtiches, which could therefor be operated slowly
>(no spring mechanism). I found I could easily generate and maintain
>copper arcs of about 3/4" between the switch contacts (No, that wasn't
>the point of the experiment, but it was fun...). Admittedly a quick
>break switch would make it harder, but then again the average small
>switch has pretty small contact gaps when open.
>
>-tony
>
>
Hi
This is why there is a condenser on the points of a car.
This allows the points to open before the coil has a chance to
build up too much voltage on the primary. The size of the
capacitor is a compromise between getting the points open
and too much current when the points close. Many older car
manuals would tell you to look at the points to determine
when the capacitor was too large or too small by the amount
of material transfered from contact to contact by the arcing.
For those that haven't tested this by hand, the primary
will kick up to about 400-600 volts because of flyback.
It will make you jump a little.
Dwight
A _very_ good day, actually. For $40 I picked up:
Apple IIe in pretty bad shape, but with DuoDisk & interface card,
SuperSerial card, and paddles.
ROM3 Apple IIgs with SCSI card.
TI-99 Expansion interface with 2 drives, RS-232 interface, and third-party
128K memory module, plus TI Extended BASIC, MultiPlan, Editor/Assembler,
Disk Manager II, and more.
And the TI stuff was in an old Apple box, for either a II+, IIe, or IIc, I
think. All it says besides "Apple" is: "The Personal Computer" in an
80s-purple-neon mall-shop-sign style script typeface.
Plus an Apple external 800K drive, some software, and a few other assorted
goodies.
It helped that the extremely nice man at Goodwill let me in the "restricted"
area of his new shop in the GW building. Nobody else gets to go back there,
so nothing had been picked through.
--
Owen Robertson
Seriously.
Somebody mentioned last week that they had questions about an Opus
card, I just saw one, a 300PM, on Dan Veeneman's page, and I have the
software (2 DC6150 QIC tapes) for a 400PM. These appear to be for
Solaris, or SunOS, and I read that Opus built "mainframe coprocessors"
for Suns as well as ATs. I think they also built standalone
workstations.
Does anybody have a matched set? Software and hardware? Ever seen
the mainframe coprocessors in action?
These things are really intriguing to me, and really mysterious.
If anybody has an SBus 400PM card and needs the software, or wants to
donate/trade it, I'm willing either way.
If somebody wants to forward this to CCtech, that'd be cool too.
Doc
I am searching for the following manuals:
PCP-88, K. Stapleford (Foxboro publication)
A Summary Description of the Standard DDC Functions, R. Rankin (Foxboro
publication)
GE/PAC 4000 Free-Time System User's manual
GE/PAC 4000 Monitor User's manual
If you've got any of these, please contact me at <sellam(a)vintage.org>.
Thanks!
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
* Old computing resources for business and academia at www.VintageTech.com *
I am searching for the following manuals:
PCP-88, K. Stapleford (Foxboro publication)
A Summary Description of the Standard DDC Functions, R. Rankin (Foxboro
publication)
GE/PAC 4000 Free-Time System User's manual
GE/PAC 4000 Monitor User's manual
If you've got any of these, please contact me at <sellam(a)vintage.org>.
Thanks!
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
* Old computing resources for business and academia at www.VintageTech.com *
I got an Omnidata Polycorder PC-602 'handheld computer' today. Does
anyone know anything about these things? Mine still seems to function,
and the recharable batteries even hold a charge. It's from about 1985,
and is programmable, and even includes some sort of terminal software
(although I don't want to rely on a 4x16 char screen for my day-to-day
things).
Thanks.
-- Pat
AFAIK...Opus had, at least, 32032, SPARC32, Clipper & 88000. They ran GNX,
SunOS & CLIX, respectively, on the first 3; dunno what Unix ran on 88k. I
*think* they also had 32016, 68020 & 32332.
I've got an 88k-based card, sans software.
Ken
