robinson@renoir.Berkeley.EDU.UUCP (03/14/87)
I have a 1080 monitor that does not seem to want to display the full width of
an NTSC frame. It formerly did not want to display the full height, but that
was easily fixed with "vert. height" control in the back.
I would like to use the extra screen space in conjunction with the morerows
command.
So has anyone figured out how to adjust the horizontal width on the 1080
monitor?
------------------------------------------------------------------------------
"If you study the logistics and heuristics of the mystics,
You will find that their minds rarely move in a line"
Fifty percent of everything is below average.
Mike Robinson USENET: ucbvax!ernie!robinson
ARPA: robinson@ernie.berkeley.eduhull@hao.UUCP (03/15/87)
The horizontal width adjustment for the Amiga 1080 monitor is a slug-tuned coil
inside the case. Not only is it inside the case, but it is positioned almost
directly under the rear portion of the bell-shaped video display tube. There
is a little more than two inches of clearance between the top of the coil and
the lower surface of the tube. Slug adjustment tools are available in a small
plastic case from Radio Shack, however, none of them are much shorter than
four inches, and cutting one off to a suitable length would eliminate the
graspable portion of the tool. To make matters worse, the Very High Voltage
line to the vdt anode passes through a plastic cable clamp (luckily removable
in non-destruct mode) only inches rearward of the coil position. Ghastly.
So...
I found it necessary to completely dismantle the 1080 to adjust horizontal
width. I recommend the following procedure, and only in the company of a
friend who not only knows the telephone number of the nearest ambulance
service, but who has also dialed the first six digits shortly before you
have arrived at the crucial step (12.) noted below:
1. Tuck your Amiga sales reciept somewhere and kiss your warranty goodbye.
2. Turn your amiga off and then remove the line cords from the wall plug.
disconnect all cables from the monitor to anything else.
3. Locate a worktable a meter or two from the Amiga cpu case.
Place the Amiga on the table with the rear of the monitor facing toward
you. With a small Phillips screwdriver, remove the two small screws in
the lower rear of the case. Set them aside where you won't inadvertently
wipe them off the table and down into the floor furnace grate (which is
where they dearly want to go).
3. Using a medium Phillips screwdriver, back the two recessed screws (at the
top of the monitor) out until they turn freely.
4. Get a towel (What they told you about towels in Hitchhiker's Guide to the
Galaxy is true) and place it on the unclutterd surface of the worktable
just in front of the monitor screen. Without rotating the monitor, grasp
the front bezel from behind with both hands, then gently and deliberately
lift the monitor over into a face down position on the towel with the bottom
of the monitor facing you. Remember while you are doing this that you have
removed some of the fasteners that hold the monitor together, and that you
wish at this point not to stress it in a way that will cause flexing or
separation of the back of the case from the front. The procedure to do
that is after the next step.
5. With the bottom of the monitor facing you, remove the four screws on the
bottom side. (I can't remember whether it is necessary to remove the ones
that hold on the rotatable feet for sure or not. I am including them
because I know it doesn't do any harm to take them out.) Now there is
nothing but gravity, friction, and the wires to the little audio jack at
the front of the monitor holding it together, so proceed as though you
knew that, please:
6. Again, slowly and deliberately, grasp the monitor as before by the front
bezel, lift it, and have your friend whisk the towel out from under it.
Using your stomach as an aft arrest, rotate the monitor back to its usual
operating position, bottom side down, but with the the back facing toward
you. Scoot it somewhat forward by pushing on the rear of the case until
you have about 1.5 case lengths of room rearwards into which you can slide
the back portion to expose the innards.
7. Separation of the front and the back of the case must be done carefully,
otherwise you may snap the wires that go to the little audio jack on the
side. It helps to have your friend go around to the other side of the
table, and, facing the monitor, grasp it by the front bezel and pitch it
ever so slighty forward so as to lift the rear of the case enough off the
table that it is under neutral force, and is free to be extracted. This
person should concentrate on maintaining the front of the monitor in such
an attitude that it behaves as though the lower front edge were glued to
the table. You must now begin to wrest the back of the case rearward by
carefully leveraged motions, making sure that in the event the retaining
friction lets go that you do not end up halfway across the room on your
back with the frayed strands of the little audio wires dangling out the
front of the rear portion of the case. It is often possible to control
this separation process by inserting a flat-blade screwdriver in the crack
between the front and back portion of the monitor and twisting. But if
you do that, please be very patient and twist only 15 to 20 degrees, else
you shall gouge the edge, and reduce the resale value of your monitor
an order of magnitude to somewhere around two bits.
8. Back the rear portion of the case off the front portion about an inch,
to where you can see the little nylon plug that retains the audio wires.
This plug is retained by a small plastic tab. It is difficult to remove,
though it can be done readily with the aid of a small pair of long-nosed
pliers and a small flat-blade screwdriver to free the tab. Sometimes
they come out easy, sometimes they are incredibly stubborn. Here, too,
you have the suddenly released friction problem to overcome, though it
is less likely to result in damage in this situation.
9. Once the plug is loose, you can back the rear portion of the case away
from the front. You will notice that the monitor is internally fairly
simple in construction, having all the beautiful perversity of the far east
traditional go-together-no-take-apart-ever-again philosophy. We should
never have left the battleship Missouri parked there. There are rails
in the lower portion of the plastic case to retain the edges of the one
printed circuit card that holds all the electronics. Corresponding rails
are to be found in the rear part, as well, and you had best remember that
they are there, and what it is they do.
10. Being careful not to curl your knuckles into the interior of the case
where all of those 25,000 volt electrons await even the most innocent
violation, slide the rear portion of the case backward until it is clear
of the front, being careful not to whack the rear end of the vdt as you
do so. In large tube displays, fracturing the rear end of the vdt, or
"neck" as it is called, can result in implosion of the tube and impalement
of the gun into whoever is standing in front when it happens. I can't
imagine that this little baby could do that, but if you break it, you
are in for a new monitor. So again I should emphasize that you should
work with smooth, deliberate motion, always manifesting control over
the balance of the forces of friction and the impulses that generate
or arrest momentum.
11. Look things over. Locate the horizontal adjustment coil, about 1/3 length
of the card from the rear, under the vdt. It should be possible to adjust
it right where it is, using a short enough tool. HOWEVER, the High Voltage
generation section is (naturally) very close to where you will be working,
looking at the monitor from the audio jack side. In most most electronics
books, they recommend that you discharge the high voltage with a metal
probe having a clip-on ground web strap and an insulated handle (for your
protection in the event that the ground clip snaps loose just as you
succeed in sneaking the probe under the rubber suction cup that surrounds
the vdt anode connection you'll see midway up the front side of the tube.)
This is not a pleasant experience, and by merely exercising deliberate
caution, it can be avoided entirely. See note below.
12. So, rather than having to worry so much about the high voltage stuff
while you are trying to adjust this coil, you might as well arrange
things so that you have lots of room. I recommend that you grasp the
printed circuit by the rear portion, opposite the side where the high
voltage transformer is located. That means you should grasp it by what,
seen from the rear of the monitor would be the left rear corner below
where the AC power cord connects when it is attached (if you observe
that the cord is still attached, then you have not been paying attention,
and are hereby disqualified from proceeding further without trained
technical assistance.) About now is when your friend needs to stand
next to the telephone. Tell your friend not to touch you while handling
the phone. Pull the card rearwards until it seems restrained by some
wiring. Cut or release any appropriate cable clamps as necessary to
pull the card far enough back that you can have an unobstructed access
to the adjustment coil from above. I had to remove the retaining screw
that holds the on/off LED to the front bezel, and cut nylon cable clamps
that retain the wiring. If you have replacement clamps, you can restore
this wiring as it was originally. However, the wires have been in the
observed positions since manufacture and are now more or less formed in
an appropriate way, so replacement of the clamps is primarily a cosmetic
endeavor.
13. Having gotten things to where you are assured you can leisurly adjust
the coil when you need to, slide the card back to the front, place a
newspaper on top of the Amiga CPU case, and then pick up the monitor by
the front bezel (as before), and place it, bottom side down on top of
the newspaper, with the screen to the right. Again, pull the card back
out of the rails until the horizontal width coil is accessable. Insert
the adjustment tool into the coil and assure yourself that you can
manipulate it while looking at the monitor screen, yet without contacting
any energized circuitry. Check again to be sure that none of the AC
power cords are presently attached. Obtain a two-socket extension cord
with grounding sockets (you know, with the third round hole implemented.
no cheating!) Stick the plug for this cord into your pocket. Plug the
Amiga CPU and the 1080 monitor power cords into the sockets on the
extension cord.
14. Connect all cables between the Amiaga CPU and monitor. It would be
perhaps better if all other peripherals were disconnected, since, in that
case, damage will be limited. Check to see that the extension cord plug is
still in your pocket and that your friend has not, seeing that it has
perhaps fallen to the floor, done you a "favor" and plugged it in to the
wall to help you. (Don't laugh. A friend of mine did the equivalent of
this for me one day by turning on the wall light switch while I was
disassembling a Jacobs ladder which was driven by a 15KV neon transformer
plugged into the overhead.) Turn the monitor and the Amiga cpu power
switches ON. Plug the Amiga CPU and the monitor power cords into their
rectangular sockets.
15. Have your friend stand in view of the monitor screen, and tell your friend
to stand ready to look for smoke, but that there should not be any. Tell
your friend as well that soon the LEDs should light, and, after the vdt
tube warms up, the Kickstart requester should appear. Now be prepared:
Take the extension cord plug out of your pocket, and plug it into the wall.
The system is now powered. Watch and listen carefully for anything you
think is abnormal, and if such is detected, yank the plug immediatly.
16. Assuming that nothing went wrong in the previous step, you are now ready
to watch and adjust. The standard television aspect ratio for horizontal
to vertical is 3 vertical units to 4 horizontal. However, the best thing
to do might be to boot a workbench and run your favorite circle generating
program, because if anything is going to be touchy, it will be circles. Use
a small ruler to measure x and y diameters if you need to. Note that when
you do this, charge will snap off the screen toward your hands. Your body
can reach damaging potentials from capacitive charge thus accumulated from
the screen. Walk away and touch a grounded object before poking any keys
on the keyboard, else you might see a half-inch arc jump from your finger
down into the innards of the keyboard. After that you may find that the
performance of your keyboard is degraded.
17. Once you have adjusted the horizontal width to your satisfaction, fill
the screen with characters (use an editor to do this) and check the color
convergence. Each white character (standard workbench colors) should
have crisp, sharp edges. If not, then you will have to adjust convergence.
Either you know how to do this or you don't. All I want to say about it
is that it is done by breaking loose the plastic tacking cement that's
gooped on the rings that surround the neck of the vdt tube. I think that
almost anyone with reasonable patience who is willing to look at the screen
and simultaneously mess with the separation of the tabs on each of the
three ring pairs can figure out how they influenc the position of the red,
green and blue dots that make up the white characters. A yellow edge means
that blue is off register, so there ought to be a blue edge on the other
side of the character stroke (maybe set the background to black to best
see what is going on). Move the rings until you have the best compromise
of color registration over the entire screen. Pay particular attention
to the left side, because that is where you will be doing much of
your character entry.
18. If convergence is satisfactory, then pull the plug and wait three or four
minutes for the high voltage electrons to redistribute themselves. You
can then disconnect all the wiring to the monitor, this time power cords
first. Keep in mind that once the power cords are disconnected, the
machine is no longer grounded, and that going near the front of the tube
will allow you to pick up potentially destructive charge. So keep away
from the front and the High Voltage wiring. Remove the coil adjustment
tool. Grasp the circuit board at the left rear (as before) and re-insert
it into the rails. Pick up the monitor from behind by the edge of the
bezel (as before). Have your friend put away the telephone and place the
towel back on the table, and then set the monitor face down on the towel.
Restore the position of all wiring (add new cable clamps if you have them).
Put the Power LED back in place, and secure the screw.
19. Pick up the rear portion of the case and lower it onto the front bezel,
aligning the rear card rails with the printed circuit card edges. Stop
when you have a three-inch gap, and locate the audio jack connector,
pulling it forward (down) toward the socket with which it will next be
re-mated. Continue pushing the case gently down until there is less
than a one-inch gap remaining. Reconnect the plug. Push down some more
until the back is seated against the front. Assymetry, funny spongy
sensations, or downright hang-ups bear investigating. Look for displaced
wiring or printed circuit misalignment. Correct problems until it goes
together smoothly. DO NOT FORCE the case onto the front piece.
20. Once the case is squarely up against the front, replace all the screws
in reversed time sequence to what you used to take the unit apart. When
done, pick up the monitor, have your friend remove the newspaper from the
Amiga, and gently set the monitor back down on top of the Amiga. Retrieve
the monitor power cord, and plug in the monitor end. Turn off the Amiga
and monitor power switches. Plug the monitor power cord into the wall,
and then when ready to sniff for smoke and watch for flames, turn the
monitor on. If nothing frightening happens, turn it off and reconnect
the Amiga power cord at both ends and then re-install all the interconnect
and peripheral wiring. You should now be ready to reboot, and once you
do that, you should again have the Kickstart requestor.
21. Load your favorite word processing program, and compose a letter to
Commodore Amiga thanking them for making the Amiga possible, and commending
them for the ease they have provided for the horizontal positioning and
vertical size adjustments. Let them know in your most colorful language
how easy it was to adjust the horizontal width. Ask them where the hell
the horizontal linearity control is. Presto, you're done.
NOTE:
I personally do not recommend that you attempt to discharge things. The
reason for my opinion is that the wiring for the high voltage really has
excellent integrity, and to violate it is to ask for trouble. Besides,
the tubes slowly recharge themselves as electrons formerly stuck in the
interstitial portions of the tube and the insulating materials gradually
sneak out onto the conducting portions of the system. You have to know
where they all are going to be coming from and going to, and that requires
training and experience. So just do this the same way you would if you
were told that in close proximity to where you are working, there is a
sleeping rattlesnake. If you don't wake him up, everything will be fine.
You just have to become psychologically prepared, in the event of a
misadventure, to get a powerful shock. If you have a weak heart, don't
attempt this adjustment. You simply have to think ahead of time about
what your involuntary nervous system is going to make you do. You must
not drop the monitor; be ready to hang on until the pain subsides, as it
very soon will. You must at all times place your hands where when you
react, you will not embed any of the sharp electronic parts into your
wrist. If you are brought in this condition to a clinic, they will
suspect you of attempted suicide, and will retain you for observation.
It is a good idea to keep one hand in a pocket, as that prevents a high
quality circuit path by which the electrons will go through the middle
portion of your body to get to where they want to go, and that is tough
on the heart.
Best Regards, Howard Hull
[If yet unproven concepts are outlawed in the range of discussion...
...Then only the deranged will discuss yet unproven concepts]
{ucbvax!hplabs | decvax!noao | mcvax!seismo | ihnp4!seismo} !hao!hull
for domain mailers: hull@hao.ucar.edugrr@cbmvax.UUCP (03/15/87)
In article <579@hao.UCAR.EDU> hull@hao.UCAR.EDU (Howard Hull) writes: > >The horizontal width adjustment for the Amiga 1080 monitor is a slug-tuned coil >inside the case. Not only is it inside the case, but it is positioned almost >directly under the rear portion of the bell-shaped video display tube. > >21. Load your favorite word processing program, and compose a letter to > Commodore Amiga thanking them for making the Amiga possible, and commending > them for the ease they have provided for the horizontal positioning and > vertical size adjustments. Let them know in your most colorful language > how easy it was to adjust the horizontal width. Ask them where the hell > the horizontal linearity control is. Presto, you're done. > > You just have to become psychologically prepared, in the event of a > misadventure, to get a powerful shock. If you have a weak heart, don't > attempt this adjustment. You simply have to think ahead of time about > what your involuntary nervous system is going to make you do. You must > not drop the monitor; be ready to hang on until the pain subsides, as it > very soon will. You must at all times place your hands where when you > react, you will not embed any of the sharp electronic parts into your > wrist. > Best Regards, Howard Hull Needless to say, Commodore *does not* recommend that untrained personnel attempt internal monitor adjustments. YOU CAN BE KILLED OR SERIOUSLY INJURED - 1) shock via contact with the High Voltage on the CRT Anode and Focus circuits. 2) shock via contact with high voltages in the horizontal deflection circuits. 3) shock via contact with line voltage present within the case. 4) trauma due to involuntary muscle contractions attendent to such shock - you have *no* control over your muscles under such conditions and can easily cut yourself severly during the shock or when you try to jerk away afterwards. 5) truma due to flying glass from CRT implosions consequent to your knocking the monitor onto the floor. The voltages remain for many minutes after power is disconnected and are not necessarily completly discharged by a single arc. The horizontal width adjustment is not user accessable because adjustment outside the normal operating range may result in damage to the monitor and because the horizontal width adjustment can also affect the High Voltage level, which is an X-RAY safety related issue. Have I covered it all? I'm not sure that Howard has done anybody a service with his detailed instructions, despite all the warnings. Anyone has enough training and/or knowledge to do this safely will not need such detailed instructions. Anyone else would be much better off to take the monitor and instructions down to their local TV or Audio-Visual repair shop. The service technicicans can make the adjustments in short order and are conversant with the safety issues involved, probably through direct and unpleasant experience. -- George Robbins - now working for, uucp: {ihnp4|seismo|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@seismo.css.GOV Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
blgardne@esunix.UUCP (Blaine Gardner) (03/16/87)
in article <1555@cbmvax.cbmvax.cbm.UUCP>, grr@cbmvax.UUCP says: > Have I covered it all? I'm not sure that Howard has done anybody a service > with his detailed instructions, despite all the warnings. Anyone has enough > training and/or knowledge to do this safely will not need such detailed > instructions. Anyone else would be much better off to take the monitor and > instructions down to their local TV or Audio-Visual repair shop. The service ^^^^^^^^^^^^ Where can I get a copy of the Commodore-Amiga service info on the 1080 monitor? > technicicans can make the adjustments in short order and are conversant with > the safety issues involved, probably through direct and unpleasant experience. True! I've been bit many times by the displays here at Evans & Sutherland. It's not fun, even when you are expecting it. I would really like to tweak in the convergence & linearity on my Amiga's monitor, can anyone tell me where to find the service info (Sams maybe)? -- Blaine Gardner @ Evans & Sutherland UUCP Address: {ihnp4,decvax}!decwrl!esunix!blgardne Alternate: {ihnp4,seismo}!utah-cs!utah-gr!uplherc!esunix!blgardne