18 Sep
2002
18 Sep
'02
4:02 a.m.
At 11:18 AM 9/17/02 -0400, Jim wrote:
I went to the Melbourne hamfest and there was almost no computer stuff there. No
Trash-80s, Commie 64s, Ataris, not even much PC stuff. But I did find a SWTPC on a junk
table!
Joe
From: Bob Shannon <bshannon(a)tiac.net>
Well, the September Flea is generally one of the largest, as all the
freshman have just arrived for the
term. But the turn-out was rather light in my opinion, due to the
weather reports.
I think the first two had the best turnout, but I missed a couple in
the middle.
I arrived rather late, so I don't know what
vintage items I may have
missed.
I was there at 9 and didn't see anything worth mentioning. It seems
like a lot of the more interesting sellers start out the summer with a
few vintagy items amid a mountain of PC/Sun/Apple and, as the summer
goes on, sell them and are left with mostly PC stuff. Also a lot of
the smaller guys seem to drop out over the course of the summer. 
18 Sep
18 Sep
5:05 a.m.
New subject: ADM-3A/HP 6144 Terminal Updates
ADM-3A/HP 6144 Terminal Updates
ADM-3A
I just "restored" a nice brown/beige ADM-3A. I got a
new CRT for USD 50, and then noticed that this unit
didn't have lower case installed. What the "lower
case" option consisted of was a lower case 2513-type
ROM and a couple of 2102-1 chips, all of which can be
inserted into sockets on the motherboard. Problem is,
the lower case 2513 LC ROM is not readily available.
So I built an adapter to make the multi-voltage 2513
PMOS chip I had from my other ADM-3A look like a 2716
to my EPROM programmer/reader. I read the upper and
lower case chips, programmed a lower case 2716, and
made a small adapter from to make the 2716 "look" like
a 2513 in the socket, installed the chips/adapter,
flipped a few switches, and voila!
This is detailed at
http://juliepalooza.8m.com/sl/adm3a-2.htm
I don't think that this is the FIRST time that this
has been done - but it might be among the last!
HP2644A
I've finished the keyboard, and got some paint that
fairly matches what I THINK that the original color of
this unit was. A several-hour long job was the buffing
of all (all) of the keys - this made a MAJOR
difference in the appearance of the unit (the keys are
NOT supposed to be chalky yellow).
I found a source for the unusual tube - but they want
USD 225 for it! They assure me that they use a type of
acrylic between the faceplate and the safety glass
that will never yellow, separate, or grow mold. Still,
this is a lot of money, and I intend to do the
hair-raising act of heating a nichrome wire (arriving
soon) to separate the faceplate from the CRT's safety
glass/front. Assuming that I survive with minimal
injury and am capable of writing anything, I will
detail this operation on my web pages.
If anyone has $225 to spend on a tube, contact me. I
beleive that this tube was also used on HP equipment
more worthy of spending $225 on.
http://juliepalooza.8m.com/sl/hp2644a.htm
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5:18 a.m.
New subject: ADM-3A/HP 6144 Terminal Updates
At 07:05 AM 9/18/2002 -0700, you wrote:
ADM-3A/HP 6144 Terminal Updates
ADM-3A
I just "restored" a nice brown/beige ADM-3A. I got a
new CRT for USD 50, and then noticed that this unit
didn't have lower case installed. What the "lower
case" option consisted of was a lower case 2513-type
ROM and a couple of 2102-1 chips, all of which can be
inserted into sockets on the motherboard. Problem is,
the lower case 2513 LC ROM is not readily available.
So I built an adapter to make the multi-voltage 2513
PMOS chip I had from my other ADM-3A look like a 2716
to my EPROM programmer/reader. I read the upper and
lower case chips, programmed a lower case 2716, and
made a small adapter from to make the 2716 "look" like
a 2513 in the socket, installed the chips/adapter,
flipped a few switches, and voila!
This is detailed at
http://juliepalooza.8m.com/sl/adm3a-2.htm
I don't think that this is the FIRST time that this
has been done - but it might be among the last!
Nice! Back in the day, at Purdue University, we modified
a number of ADM-3a terminals with a 2x PROM which
contained an APL character set. We then added a toggle
switch in the little metal plate on the left of the keyboard
and stuck stickers onto the keyboard so that you could
select normal terminal mode or APL mode and program
in APL...
--tom
HP2644A
I've finished the keyboard, and got some paint that
fairly matches what I THINK that the original color of
this unit was. A several-hour long job was the buffing
of all (all) of the keys - this made a MAJOR
difference in the appearance of the unit (the keys are
NOT supposed to be chalky yellow).
I found a source for the unusual tube - but they want
USD 225 for it! They assure me that they use a type of
acrylic between the faceplate and the safety glass
that will never yellow, separate, or grow mold. Still,
this is a lot of money, and I intend to do the
hair-raising act of heating a nichrome wire (arriving
soon) to separate the faceplate from the CRT's safety
glass/front. Assuming that I survive with minimal
injury and am capable of writing anything, I will
detail this operation on my web pages.
If anyone has $225 to spend on a tube, contact me. I
beleive that this tube was also used on HP equipment
more worthy of spending $225 on.
http://juliepalooza.8m.com/sl/hp2644a.htm
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19 Sep
19 Sep
8:46 a.m.
New subject: ADM-3A/HP 6144 Terminal Updates
Loboyko Steve wrote:
ADM-3A
I read the upper and lower case chips, programmed a lower case
2716, and made a small adapter from to make the 2716 "look" like
a 2513 in the socket, installed the chips/adapter, flipped a few
switches, and voila!
Nice work Steve, and thanks for the PROM files.
A very trivial question: can you see any particular reason why the
glyphs in the lowercase ROM run backwards (apart from "address lines 3 -
8 are inverted"!) Does this make anything simpler? I've just found the
ADM-3 Maintenance Manual, and it appears to have the same configuration,
but it just says
"... the lower case ROM is a custom masked part. The one unusual thing
about this is that all of the address lines into the lower case
character generator are inverted."
No explanation! And it can't be all of the lines on the ADM-3a, because
the 8 scan lines run top to bottom, as with the upppercase ROM.
- Paul
7:09 p.m.
New subject: ADM-3A/HP 6144 Terminal Updates
Hmmm...I never noticed that...
No, I don't see any reason to have done this, except
possibly to deliberately make it incompatible with the
"standard" lower case 2513 (I'm fairly certain that
there was one, Jameco used to sell it), so that they
could get a premium price for their part. Imagine the
suprise of someone plugging one of these chips in in
1978 or so, to see the characters jumbled up!Because I
made a copy of it without analyzing it, no problem. No
brains, no headaches.
Of course, one could make it compatible with a little
board the size of the one I made and flip the address
lines around, or cut up and jumper the PCB, but who
would want to start cutting up their $1000 terminal
for a relatively small savings? And remember, of
course, UVEPROMS were very expensive them and very few
people had programmers at their disposal.
So, that's the best I can come up with.
one unusual thing
about this is that all of the address lines into the
lower case
character generator are inverted."
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