21 Mar
2002
21 Mar
'02
9:26 p.m.
I've seeing some screen jitters on the screen of my Symbolics 3620. The
characters are sort of doubled up and horizontally offset, as if you had
two copies of the same text on a pair of overhead slides, lined them up one
over the other and then moved the top one about a half-character to the
right. Take the whole thing, make it kind of blurry and you have the
effect I see.
Is this a standard sort of monitor problem that is easily fixed by tweaking
some internal pot (I hope!) or is it likely some bigger problem? Does
anyone have any maintenance documentation on this beast or a spare monitor
they don't need?
Thanks!
-- Tony
22 Mar
22 Mar
9:05 a.m.
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23 Mar
23 Mar
2:26 a.m.
On 22 Mar, Tony Duell wrote:
Is the monitor based on a standard chassis that we
might be able to find
documentation on?
Aha. I see. You never seen a Symbolics (monitor) from inside.
These
console monitors are very special and very strange things. Mono screen,
some audio stuff in it, keyboard and mouse controller, ... and it is
connected to the machine with a single cable. They are completely
different from everything else on the world.
The symptom sounds like a broken solder point that broke some
termination of the console cable. I recommend to resolder the solder
points in the monitor before every other action is taken.
--
tschuess,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz
6:10 a.m.
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10:19 a.m.
Tony,
I used to fix lisp machines for a living. They use custom monitors.
The problem described is a common problem of reflections on the video signal
transmission line, and this accounts for the doubling of the video.
Tony Duell wrote:
On 22 Mar, Tony Duell wrote:
No. Now, if somebody wants to give me a Symbolics... :-)
Is the monitor based on a standard chassis that
we might be able to find
documentation on?
Aha. I see. You never seen a Symbolics (monitor) from inside.
These console monitors are very special and very
strange things. Mono screen,
some audio stuff in it, keyboard and mouse controller, ... and it is
connected to the machine with a single cable. They are completely
different from everything else on the world.
That, actually, doesn't mean a darn thing...
Consider the portrait monitor on my PERQ 2T1. It's got 3 physical cables
back the host, which actually form 1 'logical cable' -- video (no syncs)
: BNC, power : 3 pin DIN, everything else (syncs, keyboard/tablet power
and signals, audio, etc) : DA15.
The keybaord and mouse/tablet plug into the back of the monitor.
But inside the monitor there's a custom connector bracket which links up
all the connectors, the speaker, and so on. And a standard KME monitor
PCB.
The PERQ 3a monitor has a PCB in the base with all the interface
circuitry on it (for things like the keyboard, speaker, etc) and an
almost-identical KME PCB on top.
The Moniterm landscape monitors used on PERQ 2T2s have much the same
connector bracket as the T1 portrait monitor, a simple (very simple) PSU,
and a standard Moniterm monitor PCB.
So the fact that the monitor unit is custom doesn't mean the PCBs inside
are. In fact most companies did use standard monitor PCB.
Do you know the PCB in the Symbolics monitor is totally custom?
-tony
10:41 p.m.
On 23 Mar, Tony Duell wrote:
No. Now, if somebody wants to give me a Symbolics...
:-)
There where two big 3600 free for pickup here in Germany... :-)
Do you know the PCB in the Symbolics monitor is
totally custom?
To be honest - no. But it wouldn't surprise me. And it
wouldn't
surprise me if it is some OEM stuff. But getting docs for it is hard in
ether case.
--
tschuess,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz
22 Mar
22 Mar
10:04 a.m.
Its a pretty simple problem. Somethings wrong with the termination
of the video signal, which is most likely a ECL-level differential signal
to the monitor (which has a lot of electronics inside). Not standard at
all.
Check your cables and (fancy) connectors. Could be the cables as much or
more than the monitor itself.
Tony Eros wrote:
I've seeing some screen jitters on the screen of
my Symbolics 3620. The
characters are sort of doubled up and horizontally offset, as if you had
two copies of the same text on a pair of overhead slides, lined them up one
over the other and then moved the top one about a half-character to the
right. Take the whole thing, make it kind of blurry and you have the
effect I see.
Is this a standard sort of monitor problem that is easily fixed by tweaking
some internal pot (I hope!) or is it likely some bigger problem? Does
anyone have any maintenance documentation on this beast or a spare monitor
they don't need?
Thanks!
-- Tony
8310
days inactive
8312
days old
6 comments
4 participants
participants (4)
-
ard＠p850ug1.demon.co.uk -
bshannon＠tiac.net -
jkunz＠unixag-kl.fh-kl.de -
tony.eros＠machm.org