piner@pur-phy.UUCP (Richard Piner) (11/14/83)
The Scion Saga
(-or- How I learned to stop worrying and love The Bomb, part II)
This is the story of my search for a monitor that would work
with the Scion MA520 graphics board. I finally replaced the tube
in an Amdek 300 with a P39 phosphor tube from Clinton. See below
for part numbers. It seems that there is no monitor off the shelf
that will do the job. Sigh. I'm sorry this is so long, but with
more video chips coming out which use the interlace lines, there
may be a few of you who can find this story instructive in the
next year or two.
I got my Scion graphics board last summer. It is quite powerful,
but you pay a price. The board uses the interlace video lines.
Normal computer video boards send the same information twice per
frame. The second set of lines are the interlace lines, and in
normal computer applications, they are drawn on top of the first
set of lines. The Scion board draws the interlace lines between
the first set of lines. The result is that the phosphors on the
screen are hit by the electron beam only half as often. When I
ordered the Scion board, I asked about the band width required by
the board, and was told that 18MHz would work fine. When I got the
board, I installed it, and plugged it into my trusty BMC. Nothing!
Well, I got out a scope, and went looking. After finding out my
scope didn't have enough band width, and borrowing a better one, I
still couldn't find anything wrong with the Scion board. A friend
suggested I put more characters in memory, so I would be looking
at more beam modulation. After sending several lines to the board,
bang, I started getting things on the monitor.
Lesson one: the Scion board uses all of the scan lines! Most
video boards don't. So my BMC was not showing the top 50 lines or
so. It hadn't been a problem with my computer video, because it
wasn't modulating the first 50 lines or so. Also, most computers
don't modulate the entire scan line either. So many monitors are
set up so that some of the top and bottom lines are not on the
screen, and the left and right ends of the scan lines are not on
the screen. After some adjusting, I was able to see the lines. So
warning number one is, your monitor must be able to get all of 500
scan lines on the screen. Some monitors cannot do this.
So after getting a display, I had yet another problem. The
monitor was blinking, and I don't mean just a little bit. That was
when I learned what interlace meant. Because the phosphors are
only being refreshed half as often, I needed a monitor with a
slower phosphor. I began my search in August. I just got the
monitor running last week. So this is indeed a saga. Below, I have
listed all of the places I tried to get a monitor. Anyone who is
interested in a nice list of people who make monitors is welcomed
to it. The final solution was to replace the tube in an Amdek 300
monitor that I had bought when I got my MAX-80. I got an Amdek
300A to try with the Scion, and it was not slow enough, so it has
moved over to the MAX. Amdek does make a nice monitor.
I was surprised by how easy it was to install the new tube. For
those who may be interested, here are a few hints on how to do it.
The only special tool needed, is a very short handled phillips
screwdriver. The back of the case comes off with just six screws,
two of them hold the RCA jack in place. There is nothing attached
to the back, so it just slides out of the way. Lay the monitor
face down on something soft. Remove the connector from the neck of
the tube, then disconnect the high voltage plug from the board.
Remember, these things can store enough juice to kill you. If you
aren't sure, let the monitor sit unplugged for a couple of days.
There is one thumb screw holding the focus coils on the tube neck.
Loosen it, then break the sealing wax which holds the coil in
place. I just popped it loose with my trusty pocket knife. Be sure
to note the placement of the coil, then slide it off the tube.
There are four screws holding the tube in place. Take them off,
then remove the tube. You will need the short handled phillips for
this. Install the new tube. You will need to put some masking tape
on the new tube, put it in the same place as the tape on the neck
of the old tube. After everything is hooked up, there will be a
couple of adjustments to make. Hook the monitor up to the Scion
board then adjust the intensity. You will need to find the
internal adjustment, since the external one does not have enough
range. Next you will need to rotate the coil so that the lines are
level. Be careful with that coil. Only touch the plastic parts.
You may have to adjust the vertical and horizontal size to get
everything on the screen. All of this only took me an hour, so it
is fairly simple. If you are the kind of person who shouldn't be
trusted with sharp objects, then any computer fix-it shop should
be able to do the job for a small fee. Note that the Amdek's focus
is not perfect. They didn't have 85 columns by 40 lines in mind,
but it is good enough.
Finally, here is a list of all the different places I looked
for monitors. The results are given too. I hope that I am able to
save someone else all of this effort.
Amdek
2420 E, Oakton St., Arlington Height, IL 60005
312-364-1180
Amber 300A almost works. I had to tell them that the amber 134
phosphor was slower than the P31 green. Good monitor, but amber
is still not slow enough.
Looking into different tube from Clinton. Clinton makes a P39
tube that works in Amdek monitor!
================================================================
Clinton Electronics Corp.
6701 Clinton Rd., Rockford, IL 61131
815-633-1444
Amdek amber tube CE745Z12C134VR
Amdek P31 tube CE745Z12P31VR
Motorola P39 tube CE744M12P39GR
Replacement tube CE745W12P39VR
for Amdek 300A & 300
but with P39 phosphor, price $95.00
Mitsubishi claims Clinton makes the tube in the Scion hi-res
monitor also.
================================================================
Motorola
1299 E. Algonquin Rd., Schaumburg, IL 60196
312-576-6040 sales
312-576-5907 orders
They have one, BUT it is open chassis! When I got it, it didn't
even have a power cord! When I hooked it up, the transformer
made smoke. The only thing this was good for was putting me
on the trail of the Clinton tube. I still don't know why I took
the Amdek apart. Lucky I did, that was when I found out it
had a Clinton tube too. It took two months to get this!
Motorola model DS-3000-555 $316
P39 phosphor $ 4
composite video $ 20
cabinet for above
Technical Manufacturing Corp.
185 New Boston St., Woburn, MA 01801
617-933-0050
These guys want $150 for the box, and it doesn't even have the
holes for controls and power cord in it.
================================================================
Dotronix Inc.
160 First Street S.E., New Brighton, MN 55112
612-633-1742
They got them. Open chassis only. Everything is an option.
================================================================
Apple tech. info.
Chicago
312-577-4102
Apple III (model A3M0039) is P39, but is designed to compensate
for Apple III brain damage. Can't center the display with normal
composite video, not enough adjustment. The phosphor looks real
nice. It's a shame the electronics won't do the job.
================================================================
Mitsubishi Electronics
2200 W. Artesia Blvd., Compton, CA 90220
213-515-3993
They say they only have 19 inch hi-res CAD/CAM type monitors
at this time. Said $600 was a "good" price on the Scion monitor!
They also said the only way to get a good monitor cheap would be
to replace the tube in the Amdek with a P39 tube from Clinton.
They also claimed the best way to go with a light pen was a
fast blue phosphor rather than the infrared that Scion uses.
================================================================
Hitachi
59 RTE 17, South Allendale, NJ 07401
516-921-7200 Black & white monitors
201-825-8000 RGB Monitors
No. But they make the P39 tube in the Apple III monitor.
Why don't they put that tube in one of their own monitors?!
================================================================
N.E.C.
1401 Estes Ave., Elk Grove Village, IL 60007
312-228-5900
No. They put P39 in their new PC, but not in monitors.
Said it would be easy to get in a year. For now, forget it.
It took five tries to get anyone who knew what I was talking
about. They put me on hold, then I was disconnected. This went
on for a couple of days. I have had lots of trouble with the
phones in Chicago disconnecting me, not just these guys.
================================================================
Sanyo
1200 W. Artesia Blvd., Compton, CA 90220
213-537-5830
800-526-7043
The first number referred me to the second number. The second
said call the first. Then they said to call Steve Litterst. Why
can't a company answer a simple question. Why do they expect
their sales reps to know more than they do? Steve doesn't know
the answer. See Panasonic.
================================================================
Panasonic
1 Panasonic Way, Secquacus, NJ 07094
201-348-5200
201-348-5337
312-981-4824 (Chicago)
Bruce Dawson Asc.
Steve Litterst
317-241-1364 (Indy)
Don Brown
502-456-6666
??
I called the first number, they said call the second and so on.
Finally they told me to call Steve. It took several trys to get
Steve. He wasn't home. It turns out, he didn't know, he had me
call Don. It took three calls to get Don. He didn't know, said
he would have to find out and call me back. I'm still waiting.
I really hate this crap. Don't they want my business? I wonder
if the home office back in Japan knows how bad service is over
here?
================================================================
RCA/ Date Display
Dept. 529, Lancaster, PA 17604
717-397-7661
800-233-0162
Got an answering machine! They never called back.
================================================================
Videx
This is only a reference. When they came out with their super
video card for the Apple, I called to find out what monitors
they recommended. I talked to a young lady who sounded like a
beach blond, "fer sure". But she knew the what interlace meant.
She recommended either the Apple III monitor or the Amdek 300A.
As noted above, neither one worked, but I expect that the Apple
monitor would work with their board in an Apple. The Amdek may
not work very well. The only way to know would be to try it.
In any case, she was a help, and this is to give credit where
due.
================================================================smh@mit-eddie.UUCP (Steven M. Haflich) (11/16/83)
WARNING ---------- Remove the connector from the neck of the tube, then disconnect the high voltage plug from the board. Remember, these things can store enough juice to kill you. If you aren't sure, let the monitor sit unplugged for a couple of days. This is exceedingly dangerous! I do not know the monitor in question, but *good* high voltage power supply capacitors can easily hold significant charge much longer than `a couple of days.' Therefore, if you don't know what you are doing, DON'T!!!! Think of it as evolution in non-action. (:-[) Steve Haflich, MIT Experimental Music Studio
dya@unc-c.UUCP (11/18/83)
References: mit-eddi.925
The recommended procedure for this is to DISCHARGE the offending
high voltage anode in question with a 1.0 megohm, 10 watt resistor connected
to THE SAME GROUND THAT THE CONDUCTIVE COATING ON THE FUNNEL OF THE CRT IS !
(Most monitors have a nasty little warning like "Arc or meter H.T. to -----"
Otherwise, the resulting high voltage will most definitely wipe out even
the best CMOS and bipolar transistors which happen to be near the path of
least resistance.
In addition, you MUST wear 1)FULL FACE SHIELD and 2)HEAVY CLOTHING
at any time a cathode ray tube is exposed. Although personally, I have
broken a number of these insturments (once by sitting on an exposed neck
inadvertently !) with no ill effects, there are documented cases of
implosion which have maimed.
Also, a continuity check of ALL RELEVANT SURFACES must be made
with respect to the AC mains in accordance with UL practises.
Then there is the X-radiation problem. YOU MUST REPLACE THE TUBE
WITH A TYPE THAT AFFORDS EQUIVALENT X RADIATION PROTECTION !!!!!
{ when the HV is over 12 kV }
--David {...duke!mcnc!unc-c!urp!dya }