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Re: Three GS questions
Joe Seeley writes ...
>
> Hi there.
>
> I recently got a hold of a GS system ....
>
> 1) My Apple RGB is fuzzier and blurrier than I recall. The Finder is really
> bad and even 40 column text mode is fuzzy. ....
> If I open up the monitor, will I find a focus knob like
> there is internally on many SVGA monitors (all the ones I have opened up)? ....
>
Yes. The following is from our newsgroup's FAQs maintained on
Ground at
ftp://ground.isca.uiowa.edu/2/apple2/Faqs
http://ground.isca.uiowa.edu/2/apple2/Faqs
>>
003- What Safety precautions should I take when working
on my monitor?
Basically: unplug the monitor and let sit for a day, wear goggles,
work on a non-conductive table surface, do not stress CRT neck.
Unplugging the monitor and letting it sit for a few hours reduces
the danger of shock from stored charges; it does not eliminate it. The
usual warning for this kind of work is AVOID touching two different
circuit points at the same time. Like, don't touch the metal chassis and
the conductive surface of the CRT at the same time.
WEAR protective GOGGLES. If you should, somehow, bump or stress the
CRT neck-- as in jumping when you get shocked-- it may break. The result
may be a peaceful THOOP! or the CRT may implode in a spray of glass.
(Avoid using the CRT's neck to support the monitor in any position.)
Work on a wooden or plastic-topped table with plenty of space. Try
to position yourself, tools, and the monitor so that when you get
'stung', the chances of breaking something are reduced.
As much as posible, avoid using heavy tools of any kind. An
inadvertant tap from a mini-screwdriver is much less likely to crack the
CRT than a bonk from a full-sized screwdriver or pair of pliers.
Rubber gloves are probably a good idea so long as they do not get
in the way. Of course, pointy connections and components can puncture
gloves.
It's a good idea to clip a wire to the chassis and touch the other
end to the conductive surface of the CRT a few times before doing any
work in order to drain off any charge there.
Note: Several places in a monitor or TV carry high enough voltages to
deliver an uncomfortable shock. Draining the charge from one point does
not guarantee that other points have been discharged.
====================
From: Joe Walters
004- How do I discharge the High Voltage?
The HV charge (20,000+ volts) might not be much reduced by just waiting
a few hours (or days), especially if you are in a low humidity location
and the tube, etc., are all of good quality.
1. There is a long wire (called the anode) that goes from the high
voltage power supply to the top of the tube where it is snapped
into a hole. You can't see the hole because there is a rubber
shield built onto the wire. The end of the wire goes to a metal
clip which, without the rubber shield, looks somewhat as below.
One squeezes the clip so the end slips into the hole in the tube.
--- ---
== \ / ===== back of CRT
\ / <-- metal clip (This is what your grounded
| screwdriver needs to touch.)
[|]
[|] insulated Anode lead going to HV module
[|]
Needless to say, UNPLUG the monitor before beginning. Simply
turning it off isn't good enough.
2. Get a clip lead and clip one end to a long slender screwdriver
3. Clip the other end to the metal chassis of the TV (i.e the
metal frame parts)
4. Carefully! slip the screwdriver tip under the rubber flap on the
top of the tube until it touches the internal wire that both
holds the anode wire in place and conducts electricity.
Step 4 may result in a somewhat loud "SNAP" as the tube is discharged.
Be prepared so you don't jump and break something.
=================
005- How do I open my RGB monitor's case and get set for doing
internal adjustments or repairs?
Whatever it is you plan to fix, if you remove the monitor case, you
will probably need to unplug the cable running from the circuit board to
the Controls/Switch Module on the side of the case. Use 'whiteout',
nail polish, etc. to mark the position of the plug. In more detail ...
1. Unplug everything from the monitor & let it sit for a day.
2. Put on protective GOGGLES. Place the unit face down on a wooden or
plastic-topped surface with lots of space and good lighting. Remove the
the screws. Place the unit in nomal position.
3. Have a fat magazine ready. Slide the case off until you are able
to see the control leads plugged into the main board on the right side
of the case. Mark the plug position with 'white-out', nail polish, etc..
Unplug the connector.
4. Slide off the case while supporting the monitor and slide the fat
magazine under the circuit board to prop up the monitor from behind.
5. Discharge the HV (optional, but, generally, a good idea).
6. <Do adjustments, fixes on Monitor>
7. When done, reinstall the control assembly.
8. Still wearing GOGGLES, support the monitor, remove the magazine,
slide on the case, reconnect the plug, finish sliding on the case,
replace screws.
....
==================================
011- How do I adjust Focus and Intensity on a blurry
GS RGB Monitor?
These adjustments may also help cure display "bowing", etc..
Intensity and Focus controls are on the High Votage Module (black
module near back of circuit board) inside the case.
Follow procedure outlined earlier for safety (e.g. unplug, wait,
wear goggles, ...) and removing the case.
Note the position of the two controls on the HV Module (at the
left, back). Mark the back of the cover where handy access hole should
be. Take the case cover to another area (i.e. away from the exposed CRT
neck). Remove the control assembly from the right side of the case.
Using a Dremel tool, hole saw, ... cut an approx. 1" diameter hole
in the back of the case. Use this opportunity to give the case interior
a good cleaning. (If you wash it, be very sure it's dry before
continuing.)
Reinstall the control assembly.
Put everything back.
Reconnect cable and AC cord. Turn on the computer & monitor. Let it
sit 10-20 minutes. Use the normal side of case controls to get the
brightest, 'decent-focus' picture you can obtain.
Using a plastic TV technician's tool (and flashlight if necessary)
adjust the Intensity and Focus controls (through the hole in back) on
the HV module to get a good looking display.
Work back and forth between the back and side controls. What you're
aiming for is a display with good brightness and sharp focus when the
side controls are near their middle positions.
Cover the back hole using a piece of duct tape, a large sticker,
etc.. (The opening is a potential shock hazard, especially if the
monitor is within reach of children.)
==========================
<<
> ....
> 3) Finally, I have a 9Mhz ZipGS accelerator. I would like to make it go as
> fast as possible. I read the MiniFAQ on this but it is "mini" indeed. I read
> one section about finding a part for the upgrade but it did not lay all the
> necessary steps by a long shot. A) Is this info available anywhere? and B) Is
> it worth it? Is a 12.5 or high Mhz ZipGS that much faster than a 9Mhz to
> warranty messing with it?
> ....
Once your monitor display is nice and sharp again, you can download
Scott G's HyperCard stack ZipUpgrade.SHK for ZipGS upgrades at
ftp://ground.isca.uiowa.edu/apple2/apple16/Hypermedia/Hypercard/
and/or you can check the Accelerator FAQs (current file is
F002ACCEL.TXT) in Ground's Faqs folder at the address listed earlier.
Mainly, to upgrade from 9MHz to, say, 12MHz, you will need to swap
in a new Oscillator module (4 x 12 --> 48MHz) and new 65C816. There is a
good chance that you will, also, need to do some deglitching mods:
fatten power supply leads and, especially on a ROM-01, add +5V and +12V
jumpers to a couple Slots. (See F002POWER.TXT Faqs file.) You may need
to swap in faster RAM chips for your TAG RAM.
Each upgrade is somewhat 'experimental'.
The 9MHz/32kB ZipGS is a very nice accelerator. It's your choice
whether a roughly 25% speed increase (for 12MHz) is worth the
investments of money and time.
Rubywand