12 Sep
2002
12 Sep
'02
1:37 p.m.
I've posted some pictures of the major pieces of my collection at
http://cmcnabb.cc.vt.edu . Shown are the HP9000/832, PDP-8/E, and
PDP-11/24. Not shown are the Commodore 64, the Sun SparcClassic, the
Macintosh SE, or the Tandy 100 Portable.
12 Sep
12 Sep
5:34 p.m.
New subject: Nifty Find - HP2644A
I picked up on a $10.00 eBay Buy it now an HP2644A
terminal. This terminal uses little tapes (DC-100A's
or HP 98200A's). It's slightly beat up (mostly in
shipping in spite of the seller's best and
professional efforts), but nothing (except see below)
that I can't repair - I'm pretty sure I can get this
back to nearly original factory condition. It should
be a nice complement to some classic micro's I'm
working with. The HP 2644A is working. It even came
with the hard to replace RS-232 cable,with an edge
connector to the unit, weird. Annoying, considering
that this thing cost several $1000's in the mid
1970's. It looks like you could put 20 amps of RS-232
signal through it, given the diameter of the cable!
The 2644A's claim to fame is that it used the 8008
CPU, and has a tiny mini-operating system, pretty good
for a machine with 16K of address space. There is a
web site in Germany with a pong game that is actually
that you run on the 8008 in the terminal via a
diagnostic "back door", which I'm looking forward to
trying. I wonder who wrote it.
This unit I have doesn't have many goodies like
graphics or lower case, but for $10, what do you want.
It's built like a "mainframe", and later models used
the same everything with different boards plugged into
the backplane.
I got a few manuals with it; the 2645A and 2648A
manuals. The 2645 seems to be very similar.
A few questions:
1. The "infamous" HP 98200A tapes are REALLY awful. I
got a box on eBay, never used, in wrappers, and they
failed immediately. After taking them apart, I think I
know why. Even sealed after all these years, the oxide
was actualy coming off the tape and the reels didn't
even have clips to hold the tape on. Whatever held the
ends of the tape on originally, doesn't. Hard to
beleive that this was an HP product of that era. I've
got almost 35 year old audio casettes that still work
and sound great.
I think DC100A's and even DC2000's will work
according to what I've googled. Any comments? Of
course, I've already tackled and (probably) fixed the
"gummy" roller problem. Before I used the drives,
even. Naturally, I've given away all of my DC2000
tapes...
2. Has anyone ever seen a CRT develop mold between the
(bonded to the tube) safety glass and the tube itself?
The unit itself was probably stored indoors in a
controlled environment because it was otherwise very
clean. I'm pretty sure I can get a replacement, but it
will cost. Too bad, because the tube is really good
and not burned in whatsoever, which is very surprising
(the tape heads have zero detectable wear also). Trust
me, even if it's technically possible, I won't be
trying to separate the safety glass from the tube
itself. I hate replacing CRT's. Unfortunately, I've
gotten good at it.
3. The tab key is missing. Not broken off, just
missing. I have a "kinda close" replacement, but if
anyone has a junk HP product of that era with tall,
"Cherry" keytops, I'll take anything.
Thanks for reading!
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13 Sep
13 Sep
5:46 a.m.
New subject: Nifty Find - HP2644A
I've got some 2645's and 2647's that are not working currently, you
might get some
parts from these.
The CRT problem is bad, there is no reasonable treatment, but you can
have the tube rebuilt
at a very high cost. Or you may get lucky and find that some of my
CRT's are in better shape.
Loboyko Steve wrote:
I picked up on a $10.00 eBay Buy it now an HP2644A
terminal. This terminal uses little tapes (DC-100A's
or HP 98200A's). It's slightly beat up (mostly in
shipping in spite of the seller's best and
professional efforts), but nothing (except see below)
that I can't repair - I'm pretty sure I can get this
back to nearly original factory condition. It should
be a nice complement to some classic micro's I'm
working with. The HP 2644A is working. It even came
with the hard to replace RS-232 cable,with an edge
connector to the unit, weird. Annoying, considering
that this thing cost several $1000's in the mid
1970's. It looks like you could put 20 amps of RS-232
signal through it, given the diameter of the cable!
The 2644A's claim to fame is that it used the 8008
CPU, and has a tiny mini-operating system, pretty good
for a machine with 16K of address space. There is a
web site in Germany with a pong game that is actually
that you run on the 8008 in the terminal via a
diagnostic "back door", which I'm looking forward to
trying. I wonder who wrote it.
This unit I have doesn't have many goodies like
graphics or lower case, but for $10, what do you want.
It's built like a "mainframe", and later models used
the same everything with different boards plugged into
the backplane.
I got a few manuals with it; the 2645A and 2648A
manuals. The 2645 seems to be very similar.
A few questions:
1. The "infamous" HP 98200A tapes are REALLY awful. I
got a box on eBay, never used, in wrappers, and they
failed immediately. After taking them apart, I think I
know why. Even sealed after all these years, the oxide
was actualy coming off the tape and the reels didn't
even have clips to hold the tape on. Whatever held the
ends of the tape on originally, doesn't. Hard to
beleive that this was an HP product of that era. I've
got almost 35 year old audio casettes that still work
and sound great.
I think DC100A's and even DC2000's will work
according to what I've googled. Any comments? Of
course, I've already tackled and (probably) fixed the
"gummy" roller problem. Before I used the drives,
even. Naturally, I've given away all of my DC2000
tapes...
2. Has anyone ever seen a CRT develop mold between the
(bonded to the tube) safety glass and the tube itself?
The unit itself was probably stored indoors in a
controlled environment because it was otherwise very
clean. I'm pretty sure I can get a replacement, but it
will cost. Too bad, because the tube is really good
and not burned in whatsoever, which is very surprising
(the tape heads have zero detectable wear also). Trust
me, even if it's technically possible, I won't be
trying to separate the safety glass from the tube
itself. I hate replacing CRT's. Unfortunately, I've
gotten good at it.
3. The tab key is missing. Not broken off, just
missing. I have a "kinda close" replacement, but if
anyone has a junk HP product of that era with tall,
"Cherry" keytops, I'll take anything.
Thanks for reading!
__________________________________________________
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6:44 a.m.
New subject: Nifty Find - HP2644A
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14 Sep
14 Sep
2:19 a.m.
New subject: Nifty Find - HP2644A
Yeah, well, Tom Uban has located a rebuilder that does do exactly what I
described, at a very
high price, with no garuntee they won't destroy the tube in the process.
BTW, the CRT on HP terminals is VERY unique, it has an unsusal aspect
ration, which also means
that it has a rather unusual deflection asseembly. The tube is about 3
times wider than it is tall!
Tony Duell wrote:
The CRT problem
is bad, there is no reasonable treatment, but you can
have the tube rebuilt
at a very high cost. Or you may get lucky and find that some of my
CRT's are in better shape.
The CRT rebuilders I've come across can replace the electron gun assembly
(and sometimes rebuild the gun if a replacement is unavailable), but they
can't generally do much with the screen or glass envelope. There may be
people who can rebond a bonded faceplate, but if so they are very few and
far between.
-tony
9:28 a.m.
New subject: Nifty Find - HP2644A
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13 Sep
13 Sep
6:43 a.m.
New subject: Nifty Find - HP2644A
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10:20 a.m.
New subject: Nifty Find - HP2644A
Subject: Re: Nifty Find - HP2644A
2. Has anyone ever seen a CRT develop mold between
the
(bonded to the tube) safety glass and the tube itself?
Steve et al
This sounds like the problem I had a month or so back with the CRT in a
HP9845. Only in my case the mould spots had 'advanced' inwards from the edge
of the screen around 2-3 inches. Not pretty!
If you have a look you will probably find the 'seal' around the edge of the
front of the tube is taped over- virtually no real moisture barrier at all
for what is underneath.
Further- you will almost certainly find that the front of the tube itself
has a conventional bonded safety glass- the mould is in the layer of
transparent 'goo' used to attach an additional anti-glare 'cosmetically
appealing' dark glass to the front of the safety glass on an ordinary CRT.
The 'goo' in the case of the 9845 CRT was very similar in texture to silicon
rubber-possibly was- and the layer was a bit over an eighth of an inch
thick. Likewise the dark glass on the front.
I tried several solvents on the 'goo' (after removing CRT from 9845 of
course!) and found ordinary petrol to be fairly effective- there are no
doubt better solvents but it worked.
Judicious use of a piece of piano wire and weights was tried, with the CRT
mounted in a temporary wooden frame, but the most rapid way to get the goo
out was (you are outside or in a well ventilated area - right!) to dribble a
generous amount of petrol into the goo- wait about a minute, and carefully
dig out the softened stuff with a long thin screwdriver. It's tedious work
and I did it in several stages but it was not difficult.
End result- cleaned 'em up and got a perfectly useable CRT and separate
'anti glare' glass.
I reassembled them with an air gap and 'goo' in the screen corners only-
its easy enuff to get into the gap and clean it out now- should the need
arise again. Visually no difference- except maybe a bit brighter screen
image.
Essential point to note- make sure the tube has a bonded safety glass-- in
this case it was difficult to actually tell till I had it out and removed
all the black tape around the edge of the screen.
DaveB
Ch Ch NZ
3:50 p.m.
New subject: Nifty Find - HP2644A
Very interesting! Thanks - comments below.
--- Dave Brown <tractorb(a)ihug.co.nz> wrote:
Subject: Re: Nifty Find - HP2644A
This is indeed what is happening to mine.
2. Has anyone ever seen a CRT develop mold
between
the
(bonded to the tube) safety glass and the tube
itself?
Steve et al
This sounds like the problem I had a month or so
back with the CRT in a
HP9845. Only in my case the mould spots had
'advanced' inwards from the edge
of the screen around 2-3 inches. Not pretty! If you have a look you will probably find the
'seal' around the edge of the
front of the tube is taped over- virtually no real
moisture barrier at all
for what is underneath.
Further- you will almost certainly find that the
front of the tube itself
has a conventional bonded safety glass- the mould is
in the layer of
transparent 'goo' used to attach an additional
anti-glare 'cosmetically
appealing' dark glass to the front of the safety
glass on an ordinary CRT.
The 'goo' in the case of the 9845 CRT was very
similar in texture to silicon
rubber-possibly was- and the layer was a bit over an
eighth of an inch
thick. Likewise the dark glass on the front.
I tried several solvents on the 'goo' (after
removing CRT from 9845 of
course!) and found ordinary petrol to be fairly
effective- there are no
doubt better solvents but it worked.
Judicious use of a piece of piano wire and weights
was tried, with the CRT
mounted in a temporary wooden frame, but the most
rapid way to get the goo
out was (you are outside or in a well ventilated
area - right!) to dribble a
generous amount of petrol into the goo- wait about a
minute, and carefully
dig out the softened stuff with a long thin
screwdriver. It's tedious work
and I did it in several stages but it was not
difficult.
I'm a little nervous about screwdrivers or putty
knives and glass under vacuum. I wonder if a HEATED
wire would cut through this. Also, I've found that
acetone goes through just about anything not metal or
glass eventually.
If you've ever seen the people who replace car
windshields at work (on pre-1990's cars, anyway), they
heat a very thin wire with a blowtorch and use this to
cut the sealant. It might be hard to find this thin,
strong wire, though. Thin wire, easy. Strong wire,
easy. Thin, strong wire...
End result- cleaned 'em up and got a perfectly
useable CRT and separate
'anti glare' glass.
I reassembled them with an air gap and 'goo' in the
screen corners only-
I might use clear RTV or something similar, if I am
successful.
its easy enuff to get into the gap and clean it out
now- should the need
arise again. Visually no difference- except maybe a
bit brighter screen
image.
Essential point to note- make sure the tube has a
bonded safety glass-- in
this case it was difficult to actually tell till I
had it out and removed
all the black tape around the edge of the screen.
I think it is illegal in the US (at least for the last
40+ years) to sell a CRT without a bonded faceplate
(actually as a part of the glass). I was reading some
horror stories about what happened before this law.
Imagine a very hot tube of glass and metal (the gun
part of the tube) being shot right into your face
(because this is the direction it wants to go in when
the tube implodes). So I'm pretty sure that this will
be ok.
Considering that this tube might be hard to get,
probably expensive, and may not be or look "original"
without the faceplate, I think I'm going to make a
frame out of wood and try it. The CRT itself doesn't
seem to be burned at all, and delivers fairly crisp
characters.
Interesting that you did this so resourcefully - where
you are, I'll bet you can't get a replacement at ANY
price!
DaveB
Ch Ch NZ
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14 Sep
14 Sep
9:07 a.m.
New subject: Nifty Find - HP2644A
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16 Sep
16 Sep
4:50 a.m.
New subject: Nifty Find - HP2644A
At 08:50 PM 9/13/02 -0700, you wrote:
I'm a little nervous about screwdrivers or putty
knives and glass under vacuum. I wonder if a HEATED
wire would cut through this. Also, I've found that
acetone goes through just about anything not metal or
glass eventually.
If you've ever seen the people who replace car
windshields at work (on pre-1990's cars, anyway), they
heat a very thin wire with a blowtorch and use this to
cut the sealant.
I was going to suggest using a thin wire as you described. I've done that to remove
car windshields from the rubbery putty that they're mounted in. I used .030"
stainless steel safety wire. Tie each end to a wooden handle (section of broom handle)
and use a back and forth sawing motion to cut through the glue. If you want to heat it,
connect each end to some kind of power supply (a car battery with a big variable resistor
might work ok). I used a variac to heat a LONG piece of safety wire to cut through a big
piece styrofoam to make a 6+ foot wing for a large model airplane once. But be carefull
about variacs, remember that thier output is still connected directly to the AC line!
It might be hard to find this thin,
strong wire, though. Thin wire, easy. Strong wire,
easy. Thin, strong wire...
They do make an optical grade of RTC. You might be able to call Dow Corning and get a
sample from them. FWIW I spent yesterday afternoon carving the optical sensors that had
been potted up n this stuff. Soaking in acetone helps soften it up.
Joe
End result- cleaned 'em up and got a
perfectly
useable CRT and separate
'anti glare' glass.
I reassembled them with an air gap and 'goo' in the
screen corners only-
I might use clear RTV or something similar, if I am
successful. 
17 Sep
17 Sep
3:30 a.m.
New subject: Attn: Joe Rigdon
Sorry for the spam if you are reading this and you aren't Joe.
Joe, we have some ebay business that I've been mailing you about daily and
I haven't heard from you. I see you active here. Please contact me. I
hate to chide, but standard ebay courtesy is to contact the buyer within 48
hours. It has been 5 or 6 days now.
Thanks.
-----
Jim Battle == frustum(a)pacbell.net
13 Sep
13 Sep
9:12 a.m.
New subject: Nifty Find - HP2644A
Hi Steve,
At 10:34 PM 9/12/02 -0700, you wrote:
I picked up on a $10.00 eBay Buy it now an HP2644A
terminal. This terminal uses little tapes (DC-100A's
or HP 98200A's).
That's a pretty nifty find! The HP 2644 was HP's first product to use the DC-100
tapes. The 2644 was well covered in one of the HP Journals. According to an article in
it, the DC-100 tapes were developed jointly between HP and 3M. If so then the HP tapes
must be some of the very first ones made. Perhaps that explains why they're so failure
prone. Not only does the media fall of but usually the rubber drive belt in the tape has
crystalized and falls apart at the first attempt to use the tape. The DECTape II and
DC-100 marked tapes have a high failure rate too but well below the near 100% failure rate
for the HP marekd tapes.
It's slightly beat up (mostly in
shipping in spite of the seller's best and
professional efforts), but nothing (except see below)
that I can't repair - I'm pretty sure I can get this
back to nearly original factory condition. It should
be a nice complement to some classic micro's I'm
working with. The HP 2644A is working. It even came
with the hard to replace RS-232 cable,with an edge
connector to the unit, weird. Annoying, considering
that this thing cost several $1000's in the mid
1970's. It looks like you could put 20 amps of RS-232
signal through it, given the diameter of the cable!
The 2644A's claim to fame is that it used the 8008
CPU, and has a tiny mini-operating system, pretty good
for a machine with 16K of address space. There is a
web site in Germany with a pong game that is actually
that you run on the 8008 in the terminal via a
diagnostic "back door", which I'm looking forward to
trying. I wonder who wrote it.
Any idea what the HP part number is on the 8008? I have some old junk HP terminals of
that style and I'll save the 8008s if I can locate them.
This unit I have doesn't have many goodies like
graphics or lower case, but for $10, what do you want.
It's built like a "mainframe", and later models used
the same everything with different boards plugged into
the backplane.
I got a few manuals with it; the 2645A and 2648A
manuals. The 2645 seems to be very similar.
A few questions:
1. The "infamous" HP 98200A tapes are REALLY awful. I
got a box on eBay, never used, in wrappers, and they
failed immediately. After taking them apart, I think I
know why. Even sealed after all these years, the oxide
was actualy coming off the tape and the reels didn't
even have clips to hold the tape on. Whatever held the
ends of the tape on originally, doesn't. Hard to
beleive that this was an HP product of that era. I've
got almost 35 year old audio casettes that still work
and sound great.
I think DC100A's and even DC2000's will work
according to what I've googled. Any comments?
There have been a bunch of comments about this just in the past week so I won't
repeat them but yes the DC-100 tapes and DECTape IIs will work in the HP if you reformat
them. The DC-2000 tapes won't work, the tape is wider and the plastic housing is
thicker. The drive roller in the tape cartridge also falls half way off of the drive
roller in the drive and tears up the roller.
Of
course, I've already tackled and (probably) fixed
the
"gummy" roller problem. Before I used the drives,
even. Naturally, I've given away all of my DC2000
tapes...
2. Has anyone ever seen a CRT develop mold between the
(bonded to the tube) safety glass and the tube itself?
I've seen that in a lot of HPs including the 9845s and 9835s. I don't know if
it's mold or what but it shows up as lots of white spots inside the glass. It seems
to show up regardless of how the monitor was stored. A couple of years ago I junked seven
HP 64000 LDSs. They all had good CRTS. About a week later I found that the CRTs were the
same as that used in the 9835. :-( You might be able to locate a HP 64000 and use the CRT
from that.
The unit itself was probably stored indoors in a
controlled environment because it was otherwise very
clean. I'm pretty sure I can get a replacement, but it
will cost. Too bad, because the tube is really good
and not burned in whatsoever, which is very surprising
(the tape heads have zero detectable wear also). Trust
me, even if it's technically possible, I won't be
trying to separate the safety glass from the tube
itself. I hate replacing CRT's. Unfortunately, I've
gotten good at it.
3. The tab key is missing. Not broken off, just
missing. I have a "kinda close" replacement, but if
anyone has a junk HP product of that era with tall,
"Cherry" keytops, I'll take anything.
I may have one. I have a couple of old HP terminals of that style laying around.
I'll check when it's not raining. Remind me in a day or two if you don't hear
from me.
Joe
Thanks for reading!
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15 Sep
15 Sep
7:10 p.m.
New subject: Nifty Find - HP2644A
Steve,
There are several dealers of used HP1000 and 3000
equipment (Monterey bay Communications) that may be
able to help you with a replacement key and other
items for a few $ if you're inclined to go that route.
Google on used HP computers. Nice find. Used 264x
terminals when I was at HP and they are built like
tanks.
Lee Courtney
--- Loboyko Steve <sloboyko(a)yahoo.com> wrote:
I picked up on a $10.00 eBay Buy it now an HP2644A
terminal. This terminal uses little tapes (DC-100A's
or HP 98200A's). It's slightly beat up (mostly in
shipping in spite of the seller's best and
professional efforts), but nothing (except see
below)
that I can't repair - I'm pretty sure I can get this
back to nearly original factory condition. It should
be a nice complement to some classic micro's I'm
working with. The HP 2644A is working. It even came
with the hard to replace RS-232 cable,with an edge
connector to the unit, weird. Annoying, considering
that this thing cost several $1000's in the mid
1970's. It looks like you could put 20 amps of
RS-232
signal through it, given the diameter of the cable!
The 2644A's claim to fame is that it used the 8008
CPU, and has a tiny mini-operating system, pretty
good
for a machine with 16K of address space. There is a
web site in Germany with a pong game that is
actually
that you run on the 8008 in the terminal via a
diagnostic "back door", which I'm looking forward to
trying. I wonder who wrote it.
This unit I have doesn't have many goodies like
graphics or lower case, but for $10, what do you
want.
It's built like a "mainframe", and later models used
the same everything with different boards plugged
into
the backplane.
I got a few manuals with it; the 2645A and 2648A
manuals. The 2645 seems to be very similar.
A few questions:
1. The "infamous" HP 98200A tapes are REALLY awful.
I
got a box on eBay, never used, in wrappers, and they
failed immediately. After taking them apart, I think
I
know why. Even sealed after all these years, the
oxide
was actualy coming off the tape and the reels didn't
even have clips to hold the tape on. Whatever held
the
ends of the tape on originally, doesn't. Hard to
beleive that this was an HP product of that era.
I've
got almost 35 year old audio casettes that still
work
and sound great.
I think DC100A's and even DC2000's will work
according to what I've googled. Any comments? Of
course, I've already tackled and (probably) fixed
the
"gummy" roller problem. Before I used the drives,
even. Naturally, I've given away all of my DC2000
tapes...
2. Has anyone ever seen a CRT develop mold between
the
(bonded to the tube) safety glass and the tube
itself?
The unit itself was probably stored indoors in a
controlled environment because it was otherwise very
clean. I'm pretty sure I can get a replacement, but
it
will cost. Too bad, because the tube is really good
and not burned in whatsoever, which is very
surprising
(the tape heads have zero detectable wear also).
Trust
me, even if it's technically possible, I won't be
trying to separate the safety glass from the tube
itself. I hate replacing CRT's. Unfortunately, I've
gotten good at it.
3. The tab key is missing. Not broken off, just
missing. I have a "kinda close" replacement, but if
anyone has a junk HP product of that era with tall,
"Cherry" keytops, I'll take anything.
Thanks for reading!
__________________________________________________
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__________________________________________________
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12 Sep
12 Sep
10:22 p.m.
At 09:37 PM 12/09/2002 -0400, you wrote:
I've posted some pictures of the major pieces of my
collection at
http://cmcnabb.cc.vt.edu . Shown are the HP9000/832, PDP-8/E, and
PDP-11/24. Not shown are the Commodore 64, the Sun SparcClassic, the
Macintosh SE, or the Tandy 100 Portable.
Beautiful!! but I hope your dart players don't miss very often.
Cheers
Charlie Fox
Charles E. Fox Video Production
793 Argyle Rd.
Windsor Ontario Canada N8Y 3J8
519-254-4991 foxvideo(a)wincom.net
Check out the "Camcorder Kindergarten"
at http://chasfoxvideo.com
8132
days inactive
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14 comments
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