21 May
1997
21 May
'97
2:07 p.m.
At 08:47 PM 5/21/97 -0400, William Donzelli wrote:
And of course, grab hold of every spare chip available
off of donor machines.
William Donzelli
william(a)ans.net
I have found what seems to be a decent supply of eproms. I was looking at
an old 2400 baud fax modem for my pc, and noticed that it had what looked
like an eprom on it. I pulled the chip and peeled off the label, and it was
a 27256 eprom. I also bought a 2400 baud modem at a thrift store for $2.00
and it had a 27128 eprom in it. This was cheaper than buying the eprom by
itself. I paid $3.00 for a 2764, and didn't even price a 27128. I am going
to start picking up all of the old cheap, almost worthless modems and
grabbing the eproms out of them. You can probably pick up the modem for
less than the price of the eprom that it holds. If anyone else knows of a
cheap source of eproms or other chips, share it with us.
Isaac Davis
idavis(a)comland.com
indavis(a)juno.com
21 May
21 May
4:03 p.m.
On Wed, 21 May 1997, Isaac Davis wrote:
If anyone else knows of a cheap source of eproms or
other chips, share it
with us.
How about old PC cards? Those are a penny a dozen. Some have really useful
stuff on them (assuming they're not old enough to be classics, like the
original IBM MDA driving my second screen).
You could also try old PC motherboards. They're very cheap and have big
EPROMs.
My personal favourite is scavenging old [S]VGA cards. These are *REALLY*
cheap or even free (esp. the 256k RAM ones). A lot have EPROMs to store
their BIOS and character set. (Around 6-7 years ago, the norm in my
country of origin was to burn a new character set into EPROMs and replace
the ones on the VGA. Later they found out that was too slow and expensive,
so they stuck with soft fonts. Maybe things are similar in your respective
loci).
While we're talking about EPROMs, anyone care to suggest a cheap burner?
Preferably one I can buy in the UK, but any ideas would be lovely. I've
looked at some, but they're all in the UKP250+ price range. I'm seriously
considering building my own...
--------------------------- ,o88,o888o,,o888o. -------------------------------
Alexios Chouchoulas '88 ,88' ,88'
alexios(a)vennea.demon.co.uk
The Unpronouncable One ,o88oooo88ooooo88oo, axc(a)dcs.ed.ac.uk
9:12 p.m.
In article <Pine.LNX.3.91.970522045703.16495A-
100000(a)vennea.demon.co.uk>gt;, Alexios Chouchoulas
While we're talking about EPROMs, anyone care to suggest a cheap burner?
Preferably one I can buy in the UK, but any ideas would be lovely. I've
looked at some, but they're all in the UKP250+ price range. I'm seriously
considering building my own...
Alexios
Maplin do two under 200UKP - the EPP1-F at 162.99 and the EPP-2
199.99 (both prices inclusive of VAT). I bought a EPP1-F a long time ago
at one company I worked at and it seemed OK for small EPROMS/EEPROMS (up
to 128k x 8. Comes with a DOS-based editor and utilities but claims to
work on any computer with an RS232 and terminal software.
4:06 p.m.
On Wed, 21 May 1997, Isaac Davis wrote:
I have found what seems to be a decent supply of
eproms. I was looking at
an old 2400 baud fax modem for my pc, and noticed that it had what looked
like an eprom on it. I pulled the chip and peeled off the label, and it was
a 27256 eprom. I also bought a 2400 baud modem at a thrift store for $2.00
and it had a 27128 eprom in it. This was cheaper than buying the eprom by
itself. I paid $3.00 for a 2764, and didn't even price a 27128. I am going
to start picking up all of the old cheap, almost worthless modems and
grabbing the eproms out of them. You can probably pick up the modem for
less than the price of the eprom that it holds. If anyone else knows of a
cheap source of eproms or other chips, share it with us.
This is a great suggestion, worthy of the FAQ. Beware that you don't
cannabalize what could be considered a classic peripheral though.
Sam
-------------------------------------------------------------------------------
Computer Historian, Programmer, Musician, Philosopher, Athlete, Writer, Jackass
2 Jun
2 Jun
6:23 a.m.
New subject: Eproms... you want 'em, he's got 'em!
Due to massive amounts of caffeine & sleep deprivation, Sam Ismail said:
On Wed, 21 May 1997, Isaac Davis wrote:
> I have found what seems to be a decent supply of eproms... yadda, yadda,
yadda...
This is a great suggestion, worthy of the FAQ. Beware
that you don't
cannabalize what could be considered a classic peripheral though.
[[ Editor's Note: I've been meaning to respond to this for some time, but
the opportunity hadn't come up yet... ]]
Right, and I may be able to help you on this one...
A few months back, I won a bid (well... there weren't many bids, actually)
on AuctionWeb where the person was selling used EPROM lots... 40 to a lot.
A lot consisted of 10 each 2716's, 32's, 64's and 128's. Starting bid was
$8.00, and he had 20 or more lots for sale. I bid on three, and they never
went beyond baseline, so I sent my money, and back they came. Needless to
say, I now have a 10-year supply of eproms for myself...
Remembering this discussion, I recently contacted him by e-mail and asked
him if he had any other e-proms, like 1702's and whatnot. (I don't need
those chips, but many of you might.) Here's his directly pasted reply:
======================== reply follows ========================
Hi,
Thanks for the e-mail. Yes, we have plenty of the older Eproms like the
1702's and 2708's. Also many other components that may be of interest to
your group.
We have a web page now (www.mchoward.com) that has all of our current memory
pricing. It won't have the things you are looking for, but we can be reached
through it. Or you can e-mail me at the office mchoward(a)prismnet.com or call
me on our toll free number 1-800-490-6896. Someone is there M-F 8:30-5:30
CST and SAT 10:00-2:00 CST.
We would appreciate any business you can send our way.
Thanks,
Mel Howard
M. C. Howard Electronics, Inc.
www.mchoward.com
E-mail: mchoward(a)prismnet.com
1-800-490-6896
512-837-2525
FAX512-837-3246
========================= end of reply ========================
I have no affiliation with this person other than being a satisfied
customer, but from what I've seen he's reasonable on his prices, prompt
with shipment, and a very understanding individual as I had to delay
payment for a short period due to a family crisis (which is still going
on...).
I would recommend doing business with him, and I would be interested to
learn what other "artifacts" he has available... as you don't find many
folks with 1702's in stock, it would seem.
Anyway, I hope this gets a few more classic machines working again...
Thanks,
"Merch"
--
Roger Merchberger | If at first you don't succeed,
Programmer, NorthernWay | nuclear warhead disarmament should
zmerch(a)northernway.net | *not* be your first career choice.
8 Jun
8 Jun
5:02 a.m.
New subject: Teaneck Findings
The Teaneck NJ hamfest this past Saturday yeilded only a few old computer
pieces (good for tubes, however). I saw quite a few old micros (sorry, I
did not make notes - I am not much of a micro person). I did see...
Sun 3/110 (with a few spare cards) - a bit expensive
DEC PDP-11/70 front panel - the good kind with knobs, switches, and lights
(I purchased this)
DEC KBD01 - a true whatsit - 8085 based, in one of the LSI-11/2 desktop
boxes, RS-232 (maybe) and another D connector on back. Any clues? I have
no clue. (I purchased this as well)
DEC DELNI - a small stack
William Donzelli
william(a)ans.net
22 May
22 May
3:27 a.m.
I have found what seems to be a decent supply of
eproms. I was looking at
an old 2400 baud fax modem for my pc, and noticed that it had what looked
like an eprom on it. I pulled the chip and peeled off the label, and it was
a 27256 eprom. I also bought a 2400 baud modem at a thrift store for $2.00
and it had a 27128 eprom in it. This was cheaper than buying the eprom by
itself. I paid $3.00 for a 2764, and didn't even price a 27128. I am going
to start picking up all of the old cheap, almost worthless modems and
grabbing the eproms out of them. You can probably pick up the modem for
less than the price of the eprom that it holds. If anyone else knows of a
cheap source of eproms or other chips, share it with us.
Hamfests are the best place to pick up spare chips. Many vendors are
simply regular guys just trying to clean out their basements, others are
psuedo-commercial vendors. Of course, it is just a big crap shoot - some
fests have yeilded only boards with standard TTL/CMOS, other fests have
yeilded more exotic species ($2000 1M Rad-Hard EEPROMS (buck a tube!),
GaAs glue logic, early weird 68000 variants, etc.). Of course, the
chances of finding exactly what you need on the first try is, by Murphy's
Law, slim (it does, however, justify going to every hamfest possible!).
I must caution that we must be careful what we scrap - for example, I am
pretty sure I scrapped out a bunch of CA Naked Mini (sound familiar?)
boards three years back. Many boards to classic minicomputers are not
distinctive at all (Data General leaps to mind), but are in demand. They
same holds true for peripherals.
I think we should use this list when we need parts. Some of us
probably have mountains of chips (at least I do). If you need a specific
chip, post something to the list - perhaps one of us has a tube of the
things we never knew we needed. I do not think anyone here is out to make
money on such small deals.
Regarding EPROMS and PALs: I would stock up on them, as both are becoming
obsolete. Flash technology has nearly wiped out EPROM demand, just as GALs
and FPGAs are pushing out PALs. And if you see ANY early or wierd EPROMs,
namely 1702s and 2532s, GET THEM. Today they are quite rare, tommorrow
they will be gone.
William Donzelli
william(a)ans.net
11:05 a.m.
> I have found what seems to be a decent supply of eproms. I was looking at
> an old 2400 baud fax modem for my pc, and noticed that it had what looked
> like an eprom on it. I pulled the chip and peeled off the label, and it was
> a 27256 eprom. I also bought a 2400 baud modem at a thrift store for $2.00
> and it had a 27128 eprom in it. This was cheaper than buying the eprom by
> itself. I paid $3.00 for a 2764, and didn't even price a 27128. I am going
> to start picking up all of the old cheap, almost worthless modems and
> grabbing the eproms out of them. You can probably pick up the modem for
> less than the price of the eprom that it holds. If anyone else knows of a
> cheap source of eproms or other chips, share it with us.
Others have said that you should be careful that what you strip for parts
is not some piece of computer history. I guess you're pretty safe with
'generic' PC clone bits (although I personally preserve true-blue IBM
hardware...), but anything else should probably be kept as-is if you're
not sure about it.
On the other hand, I got some old PCBs that had had the gold connectors
cut off (for 'recycling' :-(), and I intend to at least remove the
socketed IC's from those. They're mostly common 68000 stuff + ethernet +
SCSI+ etc, but they are worth saving, and the boards are useless as-is.
Hamfests are the best place to pick up spare chips. Many vendors are
simply regular guys just trying to clean out their basements, others are
psuedo-commercial vendors. Of course, it is just a big crap shoot - some
fests have yeilded only boards with standard TTL/CMOS, other fests have
yeilded more exotic species ($2000 1M Rad-Hard EEPROMS (buck a tube!),
GaAs glue logic, early weird 68000 variants, etc.). Of course, the
chances of finding exactly what you need on the first try is, by Murphy's
Law, slim (it does, however, justify going to every hamfest possible!).
I'm always a little careful about buying chips at radio rallies
(hamfests). They're the one thing I can't fix if they are defective, so I
don't pay that much for them. On the other hand, I do buy up 2900-series
chips whenever I see them - they are sufficiently rare to be worth
grabbing.
Unlike valves (tubes), where a quick test with an Ohmmeter will tell you
if the heater is burnt out, there's no quick test for finding really dud
IC's AFAIK. Maybe I should design a pocket IC tester....
I must caution that we must be careful what we scrap - for example, I am
pretty sure I scrapped out a bunch of CA Naked Mini (sound familiar?)
Argh!!!
I think we should use this list when we need parts.
Some of us
probably have mountains of chips (at least I do). If you need a specific
Indeed. Most serious computer collectors keep all sorts of spares in their
junk box. Would you believe a spare ASR33 motor (50Hz model), head stacks
for a TU16, head assemblies for Northstar disk drives, DEC flip-chip
cards, Anadex printheads, etc, etc, etc.
chip, post something to the list - perhaps one of us
has a tube of the
things we never knew we needed. I do not think anyone here is out to make
money on such small deals.
Another thing: If you get a computer from a company, university, or
similar (as opposed to a private individual), ask if they have any spares
around. Sometimes all sorts of things turn up. I was once offered (along
with some other people) a PDP11/34 CPU. Now, they're quite common, but
also quite nice, and I grabbed one. I then asked if there were any spares
available. I was then offered an assortment of DEC comms cards (DMC11's,
DMR11's, KMC11's, DJ11's, etc), cables, boards, test boards, extenders,
RK05 heads, alignment disks, alignment tapes, PSUs, switches,
brand-new-in-bags DEC components, etc. That's just one example - it's
happened several times, and you lose nothing by asking.
Regarding EPROMS and PALs: I would stock up on them, as both are becoming
obsolete. Flash technology has nearly wiped out EPROM demand, just as GALs
and FPGAs are pushing out PALs. And if you see ANY early or wierd EPROMs,
Well, yes, but I don't insist that all my machines have all-original
components. If a PAL failed in my PERQ, I'd replace it with a GAL, no
question. The machine would work again that way. Of course, if I then saw
a suitable blank PAL I'd probably swap it in, but I'd not class it as
urgent.
Similarly, apart from the _strange_ 1702, it's often very easy to use
larger modern EPROMs in place of older ones. Or you could use EEPROMs
(Microchip et al make at least the 2K * 8 (2816) and 8K*8 (2864) ones) -
the pinout is almost the same as the 2716 and 2764.
If you are a purist, this probably won't help you, but I've used tricks
like that to get old machines running again. I wonder how many people have
noticed that if you take a 4164 64K DRAM chip (commonly available on old
PC memory cards), bend up pins 1 and 8 (N/C and +5V), and solder a jumper
from pin 8 to pin 9 (A7), the result will work in a
4116 socket (although
using only a quarter of the chip). I used that to get a very
dead Tekky
graphics terminal running again when I couldn't get a 4116 in a hurry.
namely 1702s and 2532s, GET THEM. Today they are quite
rare, tommorrow
Don't forget the 2708 and the 3-rail 2716 (Texas Instruments).
Also, how many people have programmers that can handle these? I have the
original Intel programmer (part of the MCS8i) for the 1702, and a little
thing that covers everything from the 2704 (! - it's a half-size 2708) to
the 2732 for the other classics. The latter needs repairing, but it should
be doable.
Most modern programmers _cannot_ handle 3-rail EPROMs, and the
manufacturers think you're mad for asking.
they will be gone.
William Donzelli
william(a)ans.net
--
-tony
ard12(a)eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
5:56 a.m.
On the other hand, I got some old PCBs that had had
the gold connectors
cut off (for 'recycling' :-(), and I intend to at least remove the
socketed IC's from those. They're mostly common 68000 stuff + ethernet +
SCSI+ etc, but they are worth saving, and the boards are useless as-is.
An excellent source, and it removes the dilemma of scrapping a goodie.
I'm always a little careful about buying chips at
radio rallies
(hamfests). They're the one thing I can't fix if they are defective, so I
don't pay that much for them. On the other hand, I do buy up 2900-series
chips whenever I see them - they are sufficiently rare to be worth
grabbing.
I have had very good luck at the fests. Sure, some may be duds, but I
would wager that the number is probably less than 1 in 1000 (except for
SIMMs - there are at least a few scumbags out there peddling known
defective parts).
Argh!!!
Sorry.
Indeed. Most serious computer collectors keep all
sorts of spares in their
junk box. Would you believe a spare ASR33 motor (50Hz model), head stacks
for a TU16, head assemblies for Northstar disk drives, DEC flip-chip
cards, Anadex printheads, etc, etc, etc.
Same here. About two years ago I was helping clear out a warehouse and I
took home hundreds of cardboard bins, so some of the junk is actually
getting sorted!
Don't forget the 2708 and the 3-rail 2716 (Texas
Instruments).
Actually, just about any weird old chips should be grabbed. This includes
all of the families that are long since gone (300 series ECL, 700 series
RTL, 800 and 900 series DTL, 4000 series _TTL_, etc.).
There is a company that still produces these chips (I forget the name),
buying up the old masks as the original producers pull out. These new
replacements, however, are priced for the insane and the U. S. government.
William Donzelli
william(a)ans.net
12:13 p.m.
[Buying chips at hamfests....]
I have had very good luck at the fests. Sure, some may
be duds, but I
would wager that the number is probably less than 1 in 1000 (except for
Yes, I've had good luck as well (and from a suplus place is Southampton
called 'Greenweld' who often have obscure chips at low prices). It's just
more of a risk - If I buy %random old computer for a few pounds and it
doesn't work, then I have a chance of repairing it, or at least extracting
some useful bits from it. That's not the case if I buy a dead chip.
I am quite sure that most people who sell at rallies/hamfests are honest.
Every one I've dealt with has been. It's just that the chips might have
been defective before he got them, and are being sold as untested. It's
not easy to test some devices after all...
Actually, just about any weird old chips should be
grabbed. This includes
all of the families that are long since gone (300 series ECL, 700 series
RTL, 800 and 900 series DTL, 4000 series _TTL_, etc.).
Agreed. I try to rescue all I can - it's amazing what does turn up. And
those are the sorts of devices I will buy at rallies - there's often no
other way to get them - and they are easy to test, and pretty difficult to
damage (e.g. by ESD). I don't tend to buy common EPROMs and micros, which
is how this thread got started.
Don't forget obscure linear devices as well. Does anyone know if the
LM379S got used in any cheap 'HiFi' amplifiers, and if so, which ones?
It's a dual 6W audio amplifier, which is used as a deflection amplifier in
the Vectrex video game, and as a servo amplifier in the Micropolis 1200
disk drives, used in PERQ2T1's and Tekky development systems (and
elsewhere). They're next to unobtainable now, so a source would be
welcome.
There is a company that still produces these chips (I forget the name),
buying up the old masks as the original producers pull out. These new
replacements, however, are priced for the insane and the U. S. government.
How insane? Are these price so high that I couldn't even consider buying
one, or would it be worth getting the odd device to restore a particularly
rare computer, or what?
William Donzelli
william(a)ans.net
--
-tony
ard12(a)eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
8:17 a.m.
and pretty difficult to
damage (e.g. by ESD).
You must be careful with old CMOS - most from the early 1970s will die
quite easily with just a minor shock.
TTL and the others can be abused all day...
How insane? Are these price so high that I
couldn't even consider buying
one, or would it be worth getting the odd device to restore a particularly
rare computer, or what?
I think I remember prices in the 25-50 dollar range for common glue.
William Donzelli
william(a)ans.net
6:16 a.m.
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11:25 a.m.
namely
1702s and 2532s, GET THEM. Today they are quite rare, tommorrow
Don't forget the 2708 and the 3-rail 2716 (Texas Instruments). My 1702A programmer is a unit based on a design from a
mid-70's
_Popular Electronics_ article. Toggle the addresses and data in
I found the articles on the PE 'CHAMP' (the first UK computer project) the
other day. One of the peripherals was the CHAMP-PROG - a 1702 programmer.
There's no hope of building it today (the whole thing is based round the
Intel 4040 and support devices), but I guess you could modify the design
if you were desparate.
on the front panel, hit a button, and a series of
RC-timed one shot's
apply the thoroughly bizarre sequence of programming voltages.
Yes, the programming algorithm is somewhat strange....
--
-tony
ard12(a)eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
7:15 a.m.
On Thu, 22 May 1997, A.R. Duell wrote:
--
-tony
ard12(a)eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
Does this fall under the 2.8 clause of the FAQ??
(note: I am not serious)
Sam
-------------------------------------------------------------------------------
Computer Historian, Programmer, Musician, Philosopher, Athlete, Writer, Jackass
5:54 p.m.
On Thu, 22 May 1997, William Donzelli wrote:
Regarding EPROMS and PALs: I would stock up on them,
as both are becoming
obsolete. Flash technology has nearly wiped out EPROM demand, just as GALs
and FPGAs are pushing out PALs.
I've had this question for some time now: are EPROMs and Flash <whatever>s
compatible (in terms of pin-out, levels, signals, timing, etc)?
--------------------------- ,o88,o888o,,o888o. -------------------------------
Alexios Chouchoulas '88 ,88' ,88'
alexios(a)vennea.demon.co.uk
The Unpronouncable One ,o88oooo88ooooo88oo, axc(a)dcs.ed.ac.uk
9817
days inactive
9835
days old
14 comments
8 participants
participants (8)
-
alexios＠vennea.demon.co.uk -
ard12＠eng.cam.ac.uk -
dastar＠crl.com -
idavis＠comland.com -
MARTIN＠paladio.demon.co.uk -
shoppa＠alph02.triumf.ca -
william＠ans.net -
zmerch＠northernway.net