20 Jan
2018
20 Jan
'18
4:12 p.m.
From: Al Kossow
vt11 is integrated into the 11/05 backplane on the
gt40
Right (although I had forgotten that); I listed the 11/05 separately since I
do have data on how much they've been going for - in an attempt to roughly
value the lot. The GT40, however, no idea. (I recall one was for sale on eBay
for many thousands, but I don't know if that was ever sold, and how much for.)
Noel
20 Jan
20 Jan
6:46 p.m.
There was a guy in the Netherlands (I believe) who was trying to sell a
GT40 for $14K with no delivery option.
If I were on the east coast (or just not very busy) I would have higher on
the ebay system just to get the GT40 + monitor.
Marc
On Sat, Jan 20, 2018 at 1:12 PM, Noel Chiappa via cctalk <
cctalk at classiccmp.org> wrote:
From: Al
Kossow
vt11 is integrated into the 11/05 backplane on
the gt40
Right (although I had forgotten that); I listed the 11/05 separately since
I
do have data on how much they've been going for - in an attempt to roughly
value the lot. The GT40, however, no idea. (I recall one was for sale on
eBay
for many thousands, but I don't know if that was ever sold, and how much
for.)
Noel
8:10 p.m.
On Sat, Jan 20, 2018 at 6:46 PM, Marc Howard via cctalk
<cctalk at classiccmp.org> wrote:
There was a guy in the Netherlands (I believe) who was
trying to sell a
GT40 for $14K with no delivery option.
Oof!
If I were on the east coast (or just not very busy) I
would have higher on
the ebay system just to get the GT40 + monitor.
What monitors work with the GT40? I happen to have the boardset (and
an 11/05) but not the CRT (and no lightpen). What could I drive with
those boards?
-ethan
8:32 p.m.
I think just the VR12, VR14, and the VR17.
I might have an extra VT11 backplane.
On Sat, Jan 20, 2018 at 7:10 PM, Ethan Dicks via cctalk <
cctalk at classiccmp.org> wrote:
On Sat, Jan 20, 2018 at 6:46 PM, Marc Howard via
cctalk
<cctalk at classiccmp.org> wrote:
There was a guy in the Netherlands (I believe)
who was trying to sell a
GT40 for $14K with no delivery option.
Oof!
If I were on the east coast (or just not very
busy) I would have higher
on
the ebay system just to get the GT40 + monitor.
What monitors work with the GT40? I happen to have the boardset (and
an 11/05) but not the CRT (and no lightpen). What could I drive with
those boards?
-ethan
8:58 p.m.
As I understand it, the power for the DACs actually comes from the monitor (VR12/4/7) and
thus you can?t use any monitor without some additional circuitry to provide the power to
the
DACs.
TTFN - Guy
On Jan 20, 2018, at 5:32 PM, Paul Anderson via cctalk
<cctalk at classiccmp.org> wrote:
I think just the VR12, VR14, and the VR17.
I might have an extra VT11 backplane.
On Sat, Jan 20, 2018 at 7:10 PM, Ethan Dicks via cctalk <
cctalk at classiccmp.org> wrote:
> On Sat, Jan 20, 2018 at 6:46 PM, Marc Howard via cctalk
> <cctalk at classiccmp.org> wrote:
>> There was a guy in the Netherlands (I believe) who was trying to sell a
>> GT40 for $14K with no delivery option.
>
> Oof!
>
>> If I were on the east coast (or just not very busy) I would have higher
> on
>> the ebay system just to get the GT40 + monitor.
>
> What monitors work with the GT40? I happen to have the boardset (and
> an 11/05) but not the CRT (and no lightpen). What could I drive with
> those boards?
>
> -ethan
>
11:07 p.m.
On Sat, Jan 20, 2018 at 8:58 PM, Guy Sotomayor Jr <ggs at shiresoft.com> wrote:
As I understand it, the power for the DACs actually
comes from the monitor (VR12/4/7) and
thus you can?t use any monitor without some additional circuitry to provide the power to
the
DACs.
Interesting. I didn't know that about the VT11. Seems that it
wouldn't be that hard to make an external PSU to replace that.
-ethan
11:25 p.m.
On Jan 20, 2018, at 8:07 PM, Ethan Dicks
<ethan.dicks at gmail.com> wrote:
On Sat, Jan 20, 2018 at 8:58 PM, Guy Sotomayor Jr <ggs at shiresoft.com> wrote:
I looked into it a while ago (since I have a VT11 somewhere but no tube). Too many
other projects and *work* have gotten in the way. I?ll get back to it eventually unless
someone beats me to it. ;-)
TTFN - Guy
As I understand it, the power for the DACs
actually comes from the monitor (VR12/4/7) and
thus you can?t use any monitor without some additional circuitry to provide the power to
the
DACs.
Interesting. I didn't know that about the VT11. Seems that it
wouldn't be that hard to make an external PSU to replace that.
11:44 p.m.
On Sat, Jan 20, 2018 at 11:25 PM, Guy Sotomayor Jr <ggs at shiresoft.com> wrote:
I am unlikely to beat you to it, so I will keep an eye open for anyone
attempting it.
Practically speaking, beyond playing Lunar Landar, I don't know what I
would do with a VT11/GT40 anyway.
-ethan
On Jan 20,
2018, at 8:07 PM, Ethan Dicks <ethan.dicks at gmail.com> wrote:
On Sat, Jan 20, 2018 at 8:58 PM, Guy Sotomayor Jr <ggs at shiresoft.com> wrote:
I looked into it a while ago (since I have a VT11 somewhere but no tube). Too many
other projects and *work* have gotten in the way. I?ll get back to it eventually unless
someone beats me to it. ;-) As I understand it, the power for the DACs
actually comes from the monitor...
... Seems that it wouldn't be that hard to make an external PSU to replace that.
11:06 p.m.
On Sat, Jan 20, 2018 at 8:32 PM, Paul Anderson <useddec at gmail.com> wrote:
I think just the VR12, VR14, and the VR17.
OK. I've never had any of those. I'm more wondering what modern
tubes might work.
I might have an extra VT11 backplane.
I may also have the backplane. I'm not as certain of that.
-ethan
21 Jan
21 Jan
1:04 p.m.
On Jan 20, 2018, at 11:06 PM, Ethan Dicks via cctalk
<cctalk at classiccmp.org> wrote:
On Sat, Jan 20, 2018 at 8:32 PM, Paul Anderson <useddec at gmail.com> wrote:
Remember that the GT40 is a vector drawing display, not a raster scan. So you need a tube
and associated deflection machinery that can handle high frequency X and Y deflection
waveforms accurately. This is not easy, especially with magnetic deflection. I don't
know what DEC used; CDC did it both ways with the 6000 series consoles. The original ones
had "dual radar tubes" with electrostatic deflection, hairy circuits with
3cx100a5 final amplifier tubes. The next generation, in the 170 series, had a single
large tube with magnetic deflection but still random access vector drawing. How they did
that with magnetic deflection is not clear to me, it sounds hard.
paul
I think just the VR12, VR14, and the VR17.
OK. I've never had any of those. I'm more wondering what modern
tubes might work. 
1:08 p.m.
On 1/21/18 12:04 PM, Paul Koning via cctalk wrote:
I'm sure it has been mentioned in past discussions on this topic, but a
monochrome atari video game
monitor
would likely be relatively easy to use as a GT40 display.
--tom
On Jan 20, 2018, at 11:06 PM, Ethan Dicks via
cctalk <cctalk at classiccmp.org> wrote:
On Sat, Jan 20, 2018 at 8:32 PM, Paul Anderson <useddec at gmail.com> wrote:
Remember that the GT40 is a vector drawing display, not a raster
scan. So you need a tube and associated deflection machinery that can handle high
frequency X and Y deflection waveforms accurately. This is not easy, especially with
magnetic deflection. I don't know what DEC used; CDC did it both ways with the 6000
series consoles. The original ones had "dual radar tubes" with electrostatic
deflection, hairy circuits with 3cx100a5 final amplifier tubes. The next generation, in
the 170 series, had a single large tube with magnetic deflection but still random access
vector drawing. How they did that with magnetic deflection is not clear to me, it sounds
hard.
paul
I think just the VR12, VR14, and the VR17.
OK. I've never had any of those. I'm more wondering what modern
tubes might work. 
1:12 p.m.
On 1/21/18 10:04 AM, Paul Koning via cctalk wrote:
Remember that the GT40 is a vector drawing display,
not a raster scan. So you need a tube and associated deflection machinery that can handle
high frequency X and Y deflection waveforms accurately. This is not easy, especially with
magnetic deflection. I don't know what DEC used
Electromagnetic
The deflection amps on vr14s and 17s were notorious for blowing out.
1:13 p.m.
On 1/21/18 10:12 AM, Al Kossow via cctalk wrote:
On 1/21/18 10:04 AM, Paul Koning via cctalk wrote:
the phosphor is long-persistance green
Remember that the GT40 is a vector drawing
display, not a raster scan. So you need a tube and associated deflection machinery that
can handle high frequency X and Y deflection waveforms accurately. This is not easy,
especially with magnetic deflection. I don't know what DEC used
Electromagnetic
The deflection amps on vr14s and 17s were notorious for blowing out.
1:48 p.m.
On Jan 21, 2018, at 10:13 AM, Al Kossow via cctalk
<cctalk at classiccmp.org> wrote:
On 1/21/18 10:12 AM, Al Kossow via cctalk wrote:
HP made some wonderful 17? and 19? electrostatic deflection vector displays. We had a
pile of them at
CMU driven by a custom GDP (some had 10-bit DACs, some had 12-bit DACs) that was
front-ended by
a PDP-11 (usually an 11/20). It was a *wonderful* combination!
TTFN - Guy
On 1/21/18 10:04 AM, Paul Koning via cctalk wrote:
the phosphor is long-persistance green Remember that the GT40 is a vector drawing
display, not a raster scan. So you need a tube and associated deflection machinery that
can handle high frequency X and Y deflection waveforms accurately. This is not easy,
especially with magnetic deflection. I don't know what DEC used
Electromagnetic
The deflection amps on vr14s and 17s were notorious for blowing out.
2:47 p.m.
HP1311A is what was used in Galaxy Game
https://www.hpmuseum.net/display_item.php?hw=732
The actual GG controller is a microcoded 2903 bitslice that sits on the Unibus
Supposed to be similar to the VT-48
Didn't James build something (FPGA based?) to play the game?
On 1/21/18 10:48 AM, Guy Sotomayor Jr wrote:
HP made some wonderful 17? and 19? electrostatic
deflection vector displays. We had a pile of them at
CMU driven by a custom GDP (some had 10-bit DACs, some had 12-bit DACs) that was
front-ended by
a PDP-11 (usually an 11/20). It was a *wonderful* combination!
TTFN - Guy
3:48 p.m.
On Jan 21, 2018, at 11:47 AM, Al Kossow via cctalk
<cctalk at classiccmp.org> wrote:
HP1311A is what was used in Galaxy Game
https://www.hpmuseum.net/display_item.php?hw=732
The actual GG controller is a microcoded 2903 bitslice that sits on the Unibus
Supposed to be similar to the VT-48
Didn't James build something (FPGA based?) to play the game?
James may have done something on this. I?m not sure.
I do know that the CMU GDP did not have any VLSI (or LSI) in it. It was pretty straight
SSI and MSI TTL from what I can recall with a bunch of custom built DACs. The GDP
was connected to the UNIBUS but it was a separate box (1U/2U) from the 11/20.
TTFN - Guy
On 1/21/18 10:48 AM, Guy Sotomayor Jr wrote:
HP made some wonderful 17? and 19? electrostatic
deflection vector displays. We had a pile of them at
CMU driven by a custom GDP (some had 10-bit DACs, some had 12-bit DACs) that was
front-ended by
a PDP-11 (usually an 11/20). It was a *wonderful* combination!
TTFN - Guy
22 Jan
22 Jan
3:10 a.m.
On Sun, Jan 21, 2018 at 1:04 PM, Paul Koning <paulkoning at comcast.net> wrote:
Yes. I do recall. I presently have no vector displays, not even an
oscilloscope with X-Y inputs (I have used them in the past but I don't
own any of my own).
As Tom Uban mentioned elsewhere in the this thread, an Atari vector
display could work - like the one in Lunar Lander/Asteroids (but as Al
Kossow mentioned, the DEC displays were long-persistence green, not
white). I don't own any Atari vector games either, but I do have a
buddy in town with a Lunar Lander that I've had my eye on for quite
some time (as it common with the breed, it also has blown deflector
amps, but he has some spares that need to be swapped in - the game
plays fine on an oscilloscope).
So... for the future, it seems more likely to me that I'd encounter an
Atari display than a DEC display but I'm happy to jump on whatever
floats by first.
Thanks for all the input.
-ethan
On Jan 20,
2018, at 11:06 PM, Ethan Dicks via cctalk <cctalk at classiccmp.org> wrote:
On Sat, Jan 20, 2018 at 8:32 PM, Paul Anderson <useddec at gmail.com> wrote:
Remember that the GT40 is a vector drawing display, not a raster scan. So you need a
tube and associated deflection machinery that can handle high frequency X and Y deflection
waveforms accurately. I think just the VR12, VR14, and the VR17.
OK. I've never had any of those. I'm more wondering what modern
tubes might work.
2373
days inactive
2375
days old
16 comments
8 participants
participants (8)
-
aek＠bitsavers.org -
cramcram＠gmail.com -
ethan.dicks＠gmail.com -
ggs＠shiresoft.com -
jnc＠mercury.lcs.mit.edu -
paulkoning＠comcast.net -
tom＠figureeightbrewing.com -
useddec＠gmail.com