>>Visit: www.accsys-corp.com
>
>I think most of us are looking for PDP-8's, I know I'd love one for my
>collection :^)
At BGSU's Firelands campus there's a PDP-8/e just sitting in the
electronics lab.
None of the instructors that work there with the execption of Dr. Adams has ever seen it run,
I did ask them if they would be willing to part with it but they said no. (Darn!)
But I think its because Dr. Adams has some sort of atachment to it.
Nasos wrote:
> This must be thrown out very soon.
> Anybody that wants this please contact me to arrange shipping or picking up
> from London, UK.
> Very big and heavy item.
> It seems to be OK mechanically, but rubbish comes up on LCD screen. Maybe a
> faulty chip. Anyone know which chip this is and have a spare to possibly
> get this back in full working order?
> Otherwise, it gets thrown in the skip!
No, I don't have anywhere to put it. Nor do I know what the electronics are
like. But...
Yes please, I (probably) want it. I'll come and fetch it some time soon - how
long can it wait? (my next definite London trip is end October).
But, what size paper does it use?
Philip.
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Without beating this dead horse too much more, I'd like to add a couple of
things to the mix.
(1) I've successfully formatted DSDD diskettes to 1.2MB DSHD format. I have
also formatted DSHD diskettes to DSDD 40-track and 80-track formats, with
varying degrees of success, depending on how carefully I tracked WHERE they
had been formatted.
(2) This gives rise to at least two other points which probably need to be
stirred into the mix. (a) The drive in which the diskette was formatted
determines what kind of drive will read/write it successfully. Formatting
as DSHD must take place in a 1.2MB drive. If the lower density is to be
used successfully, care must be taken to ensure that the disketted is never
written in a DSDD drive, as the heads are different and the DSHD drive can't
erase enough of what the DSDD drive's heads have written to be completely
successful all the time. (b) WHEN the diskette was made seems to make a
great deal of difference as to whether this (item #1, above) will work, i.e.
whether the DSDD diskettes will format to DSHD with whatever massaging is
required.
Eric's comments about the emulsion placed on the media is quite correct. At
some point, however, it became economically expedient to use the same
emulsion in all of their (the diskette-makers') products as opposed to
producing two different emulsions. That led to another period during which
the bin-sorting provided a market for lots which were only slightly less
"perfect" than their standards demanded, and these were then used, together
with whatever completely adequate lots were necessary to meet the demand for
DSDD media. The "perfect" lots of stock were punched and labeled DSHD.
Clearly, a goodly portion of the time, DSDD media were sold which were
completely adequate to meet DSHD requirements.
Since the DYSAN folks in Luisville, CO, who were once a customer of mine,
practiced this in fixed disk media, I doubt it was done any differently with
floppy media . . . perhaps not, but it makes sense.
Dick
-----Original Message-----
From: Eric Smith <eric(a)brouhaha.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Thursday, September 30, 1999 4:08 AM
Subject: Re: floppy controller IC (was Re: Fixing a PET?)
>Glen wrote:
>> BTW my understanding is that all 5.25 diskettes made today are
bin-sorted --
>> that is, they shoot for DSHD and the fallouts are sold as DSDD.
>
>I don't believe that for an instant.
>
>High-density requires a different, higher-coercivity coating, which will
>not work properly for low density (single or double).
>
>However, there's no difference between double density 40 track and 80 track
>disks. They aren't even binned; they just get labelled differently.
>
> In a message dated 9/30/99 9:54:17 AM US Eastern Standard Time,
> kh240463(a)stmail.staffs.ac.uk writes:
>
>> There's a poll at www.windrivers.com on what is your
>> favorite "pre-windows" system. At present the Commodore
>> 8-bits are in first place with the Amiga in second.
>>
> those numbers have got to be bogus. probably some shills involved. there were
> way more apple ][ series computers made than amigas, yet the numbers are
> really skewed...
Well, only four or five kilofolk have actually voted so far.
One source of skew could be that former Apple II people are probably less likely
to be using a Windows-95-oriented web site than former Amiga people. Another
could be that Amiga is more recent, and many voters might be too young to have
had a real appreciation of Apple II.
FWIW, I considered voting for PET - the system I grew up with - but went for
Other instead (I really like the Tek 4050 series).
Philip.
PS For the record, I wouldn't have visited the site at all had it not been
mentioned here.
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I think this thread is getting old, but as an EE I think I'd better set this one
straight...
>>Yellow-Purple-Gold-Gold resistor, then tied to ground via
>>a Grey-Red-Black-Gold (might be Sky Blue-Red-Black-Gold) and then through one
>>of the rear pots. I would spec the values, but I'm not used to such odd
>>colors
>>in the significant digits of resistors (just as tolerance bands). Would a
>>EE care to translate these? Might that second one be 92 Ohms? Could the
>>first one be 7.5 Ohms?
>
> Puzzles me too.
>
> Silver 1e-2
> Gold 1e-1
> 1 Black 1e0 First 2 digits give mantissa,
> 2 Brown 1e1 3rd digit gives exponent,
> 3 Red 1e2 4th band gives quality of resistor (if present), else +/-
20%
> 4 Orange 1e3 (silver = +/- 10%, gold= +/- 5%, red = +/- 2%)
> 5 Yellow 1e4 5th band (if present) gives reliability (mil-spec, etc.)
> 6 Green 1e5
> 7 Blue 1e6 Example: red-yellow-orange-gold = 2,4,10^3, 5% = 24k Ohm, 5%
> 8 Violet 1e7
> 9 Gray (From Horowitz & Hill, The Art of Electronics, 1st Edition
> 0 White pp. 645-646)
Ouch! No, black is zero, brown is one, up to white which is nine. The values
in the mantissa correspond then with those in the exponent.
Yellow-purple-gold-gold = 4.7 ohms as someone (Pete?) has already pointed out.
Grey-red-black-gold = 82 ohms
Blue-red-black-gold = 62 ohms
All are standard values, though 62 is less common being an E24 rather than an
E12 value (i.e. only used if you're sorting resistors into 24 values per decade,
not if you're sorting into 12)
I would guess that 82 ohms in parallel with the resistance of the pot (which
probably is wired as a potential divider) gives about 70 ohms, so the 4.7 makes
it up to 75, and doesn't let you connect the (presumably sensitive) circuit on
the input directly to the pin. This would imply a pot with resistance 470 or
500 ohms.
Philip.
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Thanks! I think I may have some information on the Kay Pro company. A friend
of my grand fathers gave me lots of computer equipment when I was about 15
years old. One of the things he gave me was a KayPro II, the one with the
two floppy drives and the Hercules monochromatic screen. I told him I liked
Kay Pro because of our old 8088 KayPro PC-10 I think it was.. (had an
NEC-V20 processor and the usual XT stuff). He said that the owner of the
company, after slowly losing profits, disbanded the company. He said that he
formed a new company making CB Radios under a different name. I do not
remember the name of the company though.
Todd,
1987 Pontiac Fiero SE / V6
1985 Pontiac Fiero GT
1984 Pontiac Fiero 2m4
1982 Pontiac TransAm V8
-----Original Message-----
From: Jim [mailto:DD950@prodigy.net]
Sent: Monday, September 27, 1999 7:18 PM
To: Discussion re-collecting of classic computers
Subject: Re: HI! Im new to the list...
-----Original Message-----
From: Todd Jaspers <ToddJ(a)symresources.com>
> Hi, im new to the list, I don't know how busy this list is, but if
>it's anything like the Fiero list.. there should be at least 100 emails a
>day
Only 100 or so postings a day huh? Well you will soon get used to the
increased volume of email on this list. :-)
Welcome to the list. I and the other three people here besides myself that
are interested in KayPro welcome you. I threw my 2X-84 away in 1995. Wish
I would have kept it. They are selling on eBay now for $35-40. :-)
I have thought of trying to collect some information on KayPro and make a
dedicated Web page. Problem is I do not have any material or knowledge of
the company and can't find any here in the boonies.
A short time ago I remarked how the Coleco Adam still had venders, User
Groups, and many Web pages while the KayPro has almost disappeared.
Welcome Aboard, oh, it is your turn to buy the next round, :-)
Regards,
Jim Rossbach, Tonkin Gulf Yacht Club Web Ring, www.TonkinYachts.cjb.net
The astonishing thing was that the newsperson managed to say "Authorities
*suspect* alcohol was involved" with a straight face.
In a message dated 09/29/1999 5:16:59 PM Eastern Daylight Time,
yakowenk(a)cs.unc.edu writes:
> Yesterday I scooped an AT&T PC 6300 Unix machine on its way
> to the dumpster. Got it home, powered it up, and now I know
> why. It displays "Parity error on system board" and locks
> up.
> It seems to have 1MB of RAM, half socketed (36 81256's).
> So I yanked the socketed chips, and tried again. Then
> it did almost the same thing, but displayed a running
> count up to 512K before that parity message.
Does this box have a BIOS setup program onboard or must you use a
configuration disk? (if so do you have the disk?)
I'd try turning off the parity check on the unlikely chance that the parity
check itself is loopy . . . other than that, you've got a _lot_ of soldering
to do ;>)
BTW ISTR that one of our "customers" abandoned a 6300 in lieu of having it
repaired. Contact me off-list if you're interested & I'll dig it out of the
back room and check it out again.
Regards,
Glen Goodwin
0/0
>> Pin 12 appears to be video. It goes off under the connector, through a 0
> Ohm
>> jumper, across a Yellow-Purple-Gold-Gold resistor, then tied to ground
> via
>> a Grey-Red-Black-Gold (might be Sky Blue-Red-Black-Gold) and then through
> one
>> of the rear pots. I would spec the values, but I'm not used to such odd
> colors
>> in the significant digits of resistors (just as tolerance bands). Would
> a
>> EE care to translate these? Might that second one be 92 Ohms? Could the
>> first one be 7.5 Ohms?
>
> Yellow-Purple-Gold-Gold = 4.7 ohms 5% tolerance
> Grey-Red-Black-Gold = 82 ohms 5% tolerance
> Blue-Red-Black-Gold = 62 ohms 5% tolerance
>
> The last is rather unlikely, since it's not an E12 or even E24 preferred
> value.
Are you sure, Pete? 62 ohms has always been an E24 preferred value in every
list I've seen. I've even seen a 62 ohm resistor with a silver (10%) tolerance
band...
Philip.
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Hey all,
Yesterday I scooped an AT&T PC 6300 Unix machine on its way
to the dumpster. Got it home, powered it up, and now I know
why. It displays "Parity error on system board" and locks
up. Actually, it displayed a bit more:
Resident Diagnostics
Ver 2.05P
CPU (i286) PASS
ROM Module PASS
DMA Timer PASS
DMA Control PASS
Interrupts PASS
Parity error on system board
It seems to have 1MB of RAM, half socketed (36 81256's).
So I yanked the socketed chips, and tried again. Then
it did almost the same thing, but displayed a running
count up to 512K before that parity message.
So, what's next? I'm guessing that at least one of the
socketed chips was bad, because it got farther before
barfing when they were removed. But there is some other
problem too, maybe in the soldered-in RAM chips, or
maybe in the parity-check circuit itself.
Anybody got a service manual or schematics or a big pile
of clues for this thing?
Cheers,
Bill.
