.The official Csa2 (comp.sys.apple2) Usenet newsgroup Apple II FAQs
  originate from the II Computing Apple II site,1997-2017.
  Csa2 FAQs text file ref. Csa2MONITOR.txt  rev225 December 2016

    Monitor.  ......

 001- How can I fix an unstable display?
 002- I'm using a TV + IIc RF module. How can I improve the display?
 003- What monitor repair Safety precautions are recommended?
 004- How do I discharge the High Voltage anode?
 005- How do I open my RGB monitor's case and get set for repairs?
 006- What tools and solder should I use for repairs?
 007- What's the fix for a flickering, Jumping, display?
 008- How can I fix an all-red, all-blue, etc. monitor display?
 009- Is there any more RGB Adjustments info?
 010- How do I adjust Centering on my GS RGB color monitor?
 011- How do I adjust Focus & Intensity on a blurry GS RGB Monitor?
 012- What is a replacement for the RGB "flyback" power transistor?
 013- How do I fix sporatic Shrinking and Flicking in-out of Focus?
 014- How do I fix a serious case of shimmy on my GS monitor?
 015- Which monitors and adapters can I use to replace my IIgs monitor?
 016- What are the pinouts for Commodore's 1084 monitors?
 017- What is a "composite video monitor"?
 018- What is the usual way to connect an Apple II to a display?
 019- How can I do the "Color Killer Mod" on a //e?
 020- My A2 display doesn't work with a "TV/Game Switch". How come?
 021- Can I use a color TV with my IIc+?
 022- What is the //c/IIc+ video port pin configuration?
 023- Where can I buy a replacement RGB monitor for my GS?
 024- What kind of RGB monitors will work with a IIc?
 025- Can I replace my GS RGB monitor with one from a PC?
 026- What are the specs and pinout for the GS RGB monitor?
 027- Do I need monochrome monitor to get a clear 80-col display?
 028- Is there a high-quality replacement for RGB monitors?
 029- Can I use a GS RGB monitor with my IIc?
 030- Why does a composite monitor I added show a fuzzy dim display?
 031- Is my SecondSight board the cause of increased system crashes?
 032- Why do Inwords and PublishIt bomb on my SecondSight board?
 033- How many dots are actually sent to the GS monitor per line?
 034- My GS RGB monitor takes a long time to get bright. A fix?
 035- Where can I get a GS RGB monitor cable?
 036- Can I replace my Apple II composite monitor with a PC VGA monitor?
 037- IIgs monitor screen goes blank and power light goes out. A fix?
 038- Why doesn't hires look as good on my GS RGB monitor?

Monitor RepairMini-Manual  (Q&A 001-014) 4/98 version

     This mini-manual describes Repairs & Adjustments which usually involve
removing the case. Before removing the case, check to see that the your
problems are not due to a poorly connected monitor cable or misadjusted monitor

From: Rubywand

001- My display is sharp but it seems to be unstable. Is there
     a quick, easy fix for this?

     Maybe. First, check your cable connections to make sure they are solid.
Also, try diddling the side and back controls. Sometimes, these become dirty or
develop bad spots.

     If diddling a control seems to cure or nearly cure an unstable, jumping,
etc. display, you can be fairly sure that a squirt of Control Cleaner will
help. The cleaner needs to reach the control's resistance element-- the place
where the wiper touches the carbon track in a potentiometer-- and you should
turn the control back and forth after squirting the cleaner. Probably, you will
need to remove the case to get a good shot at the dirty control.

= = = = = = = = = = = = = =

002- My Apple IIc has the IIc RF modulator module and is connected
     to a color TV through a TV/Game switch. The color is okay but
     the display is more or less ragged depending on where I run
     the cable. Is there a way to get a better, more stable display?

     If you are using a plain hi-fi type cable to connect from your IIc
modulator to the TV/Game switch, then, changing to a video cable may help.  If
you are using a much longer cable than necessary, try a shorter cable.

     Another popular trick is to form any unused length into one or more loops
(use wire ties or tape to hold the loops together).  Wrapping unused cable
length around a ferrite or iron core (e.g. from an old transformer) is a
variation on the same idea.

= = = = = = = = = = = = = =

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 of good quality. You can, probably, _reduce_ the shock hazard by
discharging the High Voltage at the anode. You can not, really, expect to
eliminate the shock hazard. (See WARNING below.)

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.

WARNING: After "discharging", do _not_ assume that no High Voltage is
present. Almost certainly, some High Voltage remains or may reappear
over time.


From: Rubywand

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
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.

= = = = = = = = = = = = = =

006- What tools and solder should I use for repairs?

     For any soldering use a good quality pencil-style iron rated at 25-40
watts with a holder and sponge. Use high quality (60/40 tin/lead or better)
rosin core solder (e.g. Kester "44" 20 gauge).

= = = = = = = = = = = = = =

007- How do fix a Flickering, Jumping, display which sometimes
     collapses to a line?

     If  the monitor exhibits major flickering, periodic collapse of the
display to a line, etc., then it may help to know that a common source of such
problems is one or more bad connections where the High Voltage module is joined
to the main circuit board. (This module is the black thing with a HV lead
running to the CRT-- it's near the left, back. The slotted nub controls in its
case set Focus and base Intensity.)  Often these connections look okay because
it is hard to see the small fractures in the solder surrounding the pins.

     The cure is to resolder all of the pins coming from the module (on the
under-side of the circuit board).  Before doing the soldering, clip a wire to
the metal chassis and touch the other end to each HV module pin and other
points in the area. While soldering, avoid touching anything conductive on the
monitor with anything but the iron and solder.

= = = = = = = = = = = = = =

008- Suddenly my monitor has an all-blue (all-red, etc.) screen!
     How do I fix this?

     You probably have a blown choke on the little chroma board mounted to the
back of the CRT. The choke will be connected to one of the larger, R/G/B output
transistors. Use an Ohmmeter to find the open choke. Replace the bad choke with
'one like it' or brew your own: wind about 25-30 turns of #30 wire on a small
ferrite core.

     A more detailed procedure is presented below ....

1. The part that causes the problem when it fails is a "choke" or "inductor" ,
it is mounted on a small circuit board attached to the back of the monitor tube
itself. This part looks like a small blue ceramic ball with two leads coming
out the bottom, and is color coded for 10 microhenries.

2. There are three of these items on that circuit board, and if any one of them
fails, the symptom is a screen all of one color, with total loss of any
controls of the monitor. The parts are identified by number, and what color the
screen is will tell you which one to replace.

       L6R2 for a Red screen
       L6G2 for a Green screen
       L6B2 for a Blue screen

3. You can probably get a 10 microhenry choke at Radio Shack, or it is
available for $1.28 (plus a $5 Handling charge) from Digikey Corporation at
(800) 344-4539.  They take Mastercard, Visa, and C.O.D.. The Digikey part
number is M8025-ND.

4. After replacing this part, the monitor colors may need to be readjusted via
the small color trimpots on the same circuit board.


From: David Fretz

009- Any more RGB Adjustments info?

R13- RGB Intensity
C86- Horizontal Position on RGB
C85- NTSC Color Hue Adjustment
C45- NTSC Frequency Adjustment


From: James Poore

010- How do I adjust Centering on my GS RGB color monitor?

     Color monitors do vertical and horzontal centering differently than do
monochrome monitors.  Almost all color monitors have either a jumper
arrangement or actual centering controls, sometimes both. Centering adjustments
are usually located on the PCB with no access holes, so the back will most
likely have to be removed to get to them.

     If your monitor uses jumpers, there should be 3 tabs that each jumper can
be connected to. For vertical adjustment the tabs should be marked as 'up',
'down', and center.  If your pix is too high, then you would connect the jumper
to the down tab. For horizontal adjustment the three tabs should be marked
'left', 'center', and 'right'.

     If your monitor has centering controls, then adjust for best centering.

     Many GS monitors use small tab switches to adjust centering. These are
located near the back of the main circuit board.

     Adjustment of Vertical Size, etc. via shafts on back of GS monitor can
affect centering. For small changes, these adjustments may get the job done.

     Adjustment of Intensity and Focus (see below) can affect centering.


From: Rubywand

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.)


From: "John F. Reeves" and Sam Goldwasser

012- I need to replace the High Voltage "flyback" power transistor
     in my Applecolor monitor. The part bears no manufacturer's
     mark, just two lines of text:


     What part should I get?

     The transistor is part Q502 on the PCB of the Applecolor RGB monitor,
manufactured in 1987. This is the only power transistor in the HV section, the
only one which is on a heat sink. ...."

     D1650 is a 2SD1650 which crosses to an ECG2331. You should be able to pick
one up at your local electronics shop. Try MCM Electronics, Dalbani, etc..


From: Rubywand

013- How can I fix sporatic Shrinking and Flicking
     in-out of Focus?

     Arcing from the metal brace to the HV module can cause the display to
momentarily shrink and flick out of focus.

     Follow safety and setup procedures outlined earlier.

     The cure is to bend the brace up enough to increase the arc path and clean
the surfaces involved. Apply HV dope to the brace and module where distances
are small.

     If the case interior seems pretty clogged with dust and gunk, it's a good
idea to remove the side-mounted Controls/Switch (C/S) Module and give the case
a good washing. (Be very sure it is well dried before replacing.) You should
also clean the two controls on the C/S Module with spray-in Control Cleaner.

     Before putting the case back, this may be a good time to adjust base
Intensity and Focus (the two nub controls on the HV module).  Position the
monitor so that screen is easy to see and the nub controls are accessible.

     Plug in the the C/S Module. Adjust the C/S Module controls to center
positions. Plug in the monitor to the computer. Get a Desktop display with some
text and icons. Use an insulated tool to adjust the nub Intensity and Focus
controls for maximum sharpness at 'normal' viewing intensity. A magnifying
glass is helpful to obtain max pixel sharpness.

= = = = = = = = = = = = = =

014- Suddenly my GS monitor exhibits a serious case of display
     shimmy which sometimes degenerates into jagged lines. How
     can I fix this problem?

     Side-to-side shimmy indicates that Horizontal lock is not stable.

     A good fix try is to adjust Horizontal Hold (the "<- ->" knob/stub) until
the shimmy stops. This usually works unless  1- The HH control is already at
its extreme setting,  2- The HH control has 'dirty' or burn spots at the
position which would, ordinarily, be the correct setting,  3- The display
stabilizes but ends up moved too far to the left or right side of the screen.

     If, adjusting Horizontal Hold does not fix the problem, you will probably
need to remove the case. For starters, this will let you squirt some Control
Cleaner into the HH control.

     With the case removed, you will have access to some other controls which
may help solve the shimmy problem. Two are on the black High Voltage module:
one nub controls base Intensity; the other controls Focus. There are also a
couple small tab switches located near the back edge of the main circuit board.
One sets Horizontal position; the other sets Vertical position.

     If you reconnect the side controls and power cord, you will be able to
experiment with adjustments.

     Working with monitor adjustments with the case removed requires constant
awareness of potential hazards. For example, you would connect the AC power
cord to the monitor _before_ plugging it into an AC socket. The monitor needs
to be on a plastic or wooden table with nearby clutter removed. It may be
easiest to support with the rear of the circuit board resting on a thick

     You should have one or two plastic TV technician tools. These are rods
with ends for turning slotted controls.  (A whole set will cost a few dollars
at Radio Shack.)  Such tools are handy for adjusting the controls on the back
of the HV module, for flipping the tab switches, for tapping components you
suspect may be loose, etc..

Note: If the HH control seems to have serious burn spots-- e.g. you notice a
crunchy feel when turning the knob-- you may have to get it replaced in order
to achieve a correct setting. Replacing such a control is a job for someone
with experience in working with monitors or TV's. If you decide to do it, be
sure to check safety and setup suggestions listed earlier. De-solder the
control, remove it, and take it to an electronics parts seller to get a

     Working with Horizontal Hold, the Horizontal tab switch, and the Intensity
control on the HV module, (and, maybe, the Focus control and Vertical Size) you
should be able to eliminate any shimmy and end up with a properly sized and
positioned display.

Note: On some monitors, you may have to trade-off Vertical Size in order to get
a stable display which retains good linearity.

     Once the shimmy problem is cured and the display is the right size and
positioned correctly, work back and forth between the side controls and Focus
to get a sharp display.

=======  End of Monitor Repair Mini-Manual =========

From: Michael Hickey, G. Utter, Jeff Blakeney, Steve Jensen, Blake Patterson,
      Scott Alfter, Louis Schulman, James Keim, Faisal Karmali, John Fenske

015- Which monitors and adapters can I use to replace my IIgs monitor?

     You should keep an eye out for any analog RGB monitor that can horizontally sync
down to 15.75 kHz. These include:

     AppleColor RGB Monitor replacement (model A2M6014, the IIgs monitor)
     Commodore 1084 models and equivalents like the Magnavox Professional 80
     Sony CPD 1302 MultiSynch
     NEC MultiSync (original), MultiSync II, MultiSync 3D
     Commodore 1902 (although most of these only do digital RGB)
     Tandy CM-8 (not sure about model but it was used with the Coco3)
     Atari SC1224 (used with the ST series)
     Some TVs

     For example, I just tried a Sony CPD 1302 multisych monitor on a GS and it works
perfectly; and, it has a .25 dot pixel! Very crisp picture. I used a standard cable from a
Mac II (or you could check with Redmond Cable http://www.redcab.com/ ).

     The NEC MultiSync II is another excellent monitor that will sync down to 15 kHz.
(The MultiSync IIA won't work, though.)  A cable you can use is shown below:

NEC Multisync II Dsub-9     IIgs Dsub-15

1 Red                        2 Red
2 Green                      5 Green
3 Blue                       9 Blue
4 Horizontal Sync            3 Composite Sync
5 Vertical Sync (NC)*
6 Red GND                    1 Red GND
7 Green GND                  6 Green GND
8 Blue GND                  13 Blue GND

*Note: DO NOT hook up Pin 5 (Vertical Sync); just chop it off. The NEC
Multisync II is capable of composite sync on its horizontal sync pin.

     The Atari SC1224 used with the ST is a ~15 kHz monitor. There were several
versions, one by Goldstar, which appeared in one of the two case styles used by
Atari over the years and bore the Atari logo. It works fine with the IIgs, provided
an adapter cable is created. Redmond Cable can provide it.

     The Commodore Amiga 1084 monitors and Magnavox equivalents (e.g.
Professional 80, 8CM515) will work with the Apple IIgs. You will need a special
Dsub-9 to Dsub-15 cable:

1084 model with Dsub-9      IIgs Dsub-15
(Analog mode)

1 GND                       13 GND (Blue)
3 Red                        2 Red
4 Green                      5 Green
5 Blue                       9 Blue
7 Composite Sync             3 Composite Sync

1084 model with DIN-6       IIgs Dsub-15
Analog Connector

1 Green                      5 Green
2 Horizontal Sync            3 Composite Sync
3 GND                        1, 6, 13 GND's
4 Red                        2 Red
5 Blue                       9 Blue
6 Vertical Sync (NC)*

*Note: DO NOT hook up Pin 6 (Vertical Sync). Just chop it off.


From: Ruud

     Here's a different approach: my Powermac 7500 is right next to my IIgs; so, I
plugged its composite video output into the video-in port of the 7500, started
Apple Video Player, and lo and behold, it is possible to use your 1024x768
multires RGB Powermac monitor as a IIgs monitor, in a pinch. Color is all
washed up, but mono is OK.


From: Stefan Voss, Joakim Ögren

016- What are the pinouts for Commodore's 1084 monitors?

1084 & 1084S Monitor Analog Connector
6 PIN DIN FEMALE viewed at the monitor

     _______       Pin#      Signal
    /   3   \      Pin 1     G  Green
   / 2     4 \     Pin 2     HSYNC Horizontal Sync
  |     6     |    Pin 3     GND Ground
   \ 1  _  5 /     Pin 4     R  Red
    \__/ \__/      Pin 5     B  Blue
                   Pin 6     VSYNC Vertical Sync

1084 & 1084S Monitor Digital Connector
8 PIN DIN 'C' FEMALE viewed at the monitor

     _______       Pin#      Signal
    /   2   \      Pin 1     NC not connected
   / 4     5 \     Pin 2     R  Red
  | 1   8   3 |    Pin 3     G  Green
   \ 6  _  7 /     Pin 4     B  Blue
    \__/ \__/      Pin 5     I  Intensity
                   Pin 6     GND Ground
                   Pin 7     HSYNC Horizontal Sync
                   Pin 8     VSYNC Vertical Sync

Commodore 1084d & 1084dS  Analog/Digital Connector
9 PIN D-SUB FEMALE viewed at the monitor
  \ 5 4 3 2 1 /

Pin  Name    Analog Mode     Digital Mode
 1   GND      Ground          Ground
 2   GND      Ground          Ground
 3   R        Red             Red
 4   G        Green           Green
 5   B        Blue            Blue
 6   I        not used        Intensity
 7   CSYNC    Composite Sync  not used
 8   HSYNC    not used        Horizontal Sync
 9   VSYNC    not used        Vertical Sync


From: Rubywand

017- What is a "composite video monitor"?

     A composite video monitor is a display which requires a composite video
signal such as that output by an Apple II computer. The signal is called
"composite" because it is a mix of Video, Horizontal Sync, and Vertical Sync
signals. A color composite video signal will, also, include Color Burst. These
signals are separated inside the monitor.

     The cable for connecting such a monitor is a single wire surrounded by
insulation with an outer shield (usually braided copper) covered by insulation.
The inner wire carries the signal, the shield is at 'ground'. Often, each end
of the cable has a standard RCA plug-- so; the cable looks much like a normal
audio hi-fi cable. (In fact, a decent hi-fi cable will, often, work fine for
connecting your Apple II to a composite color monitor.)

     The main differences between a hi-fi cable and one intended to carry video
signals are  1) the video cable usually has a better, tighter shield;  2) the
video cable is characterized for impedance matching at, usually, 50 or 75 Ohms;
and  3) the video cable exhibits lower capacitance between the center lead and
the shield.

     You can connect your Apple II to a Monochrome or Color composite video


From: Michael Pender and Rubywand

018- What is the usual way to connect an Apple II to a display?

     For a IIgs, you connect to the IIgs RGB monitor. For other Apple II's, you
use a video quality 'RCA cable' to connect to a composite color monitor, such as
one of the Apple II monitors or a third party monitor like the Amdek Color-1.
(The IIgs has a composite color output which can go to a composite monitor;
but, for IIgs super-res, the results are unsatisfactory.)

     An alternative to a composite monitor is to connect to a color TV directly or
through a VCR. Most VCRs and many modern televisions have a composite
video input port. Rather than buying a new monitor, a person can usually use an
RCA cable to connect the Apple to a spare VCR or television.  The stabilization
logic built into even a cheap VCR can go a long way toward cleaning up an ugly


From: Rubywand

019- Does anybody know how to do the "Color Killer Mod"
     on a //e?

     It looks like you should be able to do a full-screen color-killer on a IIe
by using a general purpose NPN  transistor (2N3904, 2N2222, etc.) to shunt the
Color Burst signal. The transistor's collector would connect to the junction of
R15 and R13; the emitter lead would go to Ground. The transistor should be
connected directly to the R15-R13 junction and ground.

     The base lead would go through a 2k-3k Ohm resistor to an annunciator
output, such as An-3 at pin 12 on the 16-pin J-15 Game connector. PEEKing the
appropriate addresses should flip Color OFF and ON.

     The reason for qualifiers such as "looks like", etc. is that I have not
actually tried a mod like this on a IIe. Monitors are remarkably sensitive to
Color Burst. If the transistor does not do a good job of shunting the signal,
enough may get through to trigger Color-ON.

     A more positve (but less easy) technique is to use a 74LS32 OR gate to
control flow of the 3.58MHz signal. The IC could be tack-soldered onto U88 via
its +5 and GND pins. U88 is the 74S02 which has the gate which produces Color

     Pin 12 of the 'S02 would be bent up and connected to the output of an
'LS32 OR gate (e.g. pin 3). One of the OR gate's inputs (pin 2) would go to Pin
12 of the 'S02 socket. The other (pin 1) would go to an annunciator output.

     Turning ON the annunciator forces the OR gate output to "1" and eliminates
Color Burst. Turning OFF the annunciator lets the OR gate output follow the
3.58MHz signal and enables Color Burst.


020- I connected my IIe to a color TV using a Radio Shack
    "TV/Game Switch" but it doesn't work. How come?

     A "TV/Game" switch is, usually, intended to switch RF (radio frequency)
signals. For example, in the "TV" position it connects the TV's VHF antenna
input to the VHF antenna (e.g. the long "rabbit ears").  This way, you can
watch TV.

     In the "Game" position it connects the TV's VHF antenna input to a game
machine's or computer's CH 3 or CH 4 output. To see the computer's display, you
need to set the TV Channel selector to the channel being output by the

     The reason your setup does not work is that the IIe does not output an RF
signal. (In fact, no Apple II has built-in circuitry for outputting an RF
signal.) The IIe outputs composite video. Composite video is pure video
information like the kind output by a VCR through the standard 'Yellow' cable.
It produces a better, sharper image than video which is converted to RF and fed
into a TV's antenna input.

     The usual way to connect an Apple II to a display is described in Q&A 018.

     Getting an "RF Converter" ("TV Converter", etc.) module is another way to go.
For about $30 Radio Shack sells a box which will convert an Apple II's video
signal to RF on CH3 or CH4.

     One thing to consider when looking for ways to connect to a color TV without
a standard "Video" input is that you could end up wasting time and money better
spent on just getting a standard composite color monitor (like the Amdek Color-1)
at a local Apple II swap meet.


021- Can I use a color TV with my IIc+?

     Yes. You can use one of the methods described above, or (for TV's with an
S-Video input) some module for converting to S-video (e.g. Video Turtle);  or,
you can use the RF Modulator module especially designed for the IIc series.

     The IIc RF module is formed to fit the IIc case and has a "CH3-CH4" slide
tab on the top. Once the module is plugged in and a cable run to the TV's
antenna inputs or to a TV/Game switch, you can get very nice, colorful on-TV
hires and double-hires displays.


From: David Empson

022- A friend with Apple //c's and IIc+'s wants to connect them to RGB
     monitors. What is the //c/IIc+ video port pin configuration?

     First, I should correct a misconception: the video port on the back of the
IIc+ is _not_ an RGB port.  It is a video expansion port, which provides all of
the internal video generation signals used by the IIc/IIc+ which can be used to
generate an alternative video output signal.

The actual functions of the IIc video port are as follows:

1   TEXT     Indicates text mode is active (spcl fn in DHR mode)
2   14M      14 MHz clock sigal
3   SYNC     Horizontal and vertical sync
4   SEGB     Vertical counter signal from IOU, or lo-res indication
5   1VSOUND  Sound output (one volt peak-to-peak)
6   LDPS     Video shift load enable
7   WNDW     Active area display blanking
8   +12V     +12 volts DC
9   PRAS     RAM row address strobe
10  GR       Graphics mode enable
11  SEROUT   Serialized character generator output
12  NTSC     Composite NTSC video output
13  GND      Ground reference
14  VIDD7    Bit 7 of video shift latch (hires mode col shifting)
15  CREF     Colour reference timing signal

These come from the IIc Technical Reference, both first and second editions.

     You cannot connect a monitor directly to the IIc video port (with the possible
exception of the the LCD display, or an NTSC monitor). To produce RGB
output (or anything else) from this port, you need an external adapter box.

     This adapter is not simple: it has to decode the colour information from the
NTSC video signal (or generate it by detecting the graphics mode and monitoring
bit patterns), generate appropriate sync signals, etc.

     I believe there is (or was) an RGB output adapter for the IIc, which should
also work on the IIc+.


From: James Stafford

023- Where can I buy a replacement RGB monitor for my GS?

     Alltech Electronics sells RGB monitors that they specially set up for the
Apple II for arround $150.00 I believe. These monitors were Atari monitors
that they fixed to work on Aplle II's. Alltech also has used IIgs RGB

     For other sources, see the Vendors page.


From: David Empson

024- What kind of RGB monitors will work with a IIc and a Laser 128?

I don't know about the Laser.  The IIc doesn't have built-in RGB output.  Its
video port provides several low-level timing signals which allow RGB data to be
decoded from the composite video signal (which is also provided on the port),
but this requires external hardware.

The "standard" IIc RGB adapter (assuming there was one) would probably have
produced digital RGB output, the same as the Apple III and the Apple IIe memory
expansion cards with RGB output.  With a digital RGB monitor, standard digital
logic levels (TTL) indicate whether a colour (or colour weighting) is present
or absent.  One wire is required for each bit of each primary colour.

The IIgs, on the other hand, produces an analog RGB signal - a voltage on the
Red, Green and Blue outputs represents the intensity of each primary colour.
Any number of shades of each colour can be supported, by providing a finer
resolution digital to analog converter within the computer.  The IIgs has 4-bit
D-to-A for each primary colour.  High-end video cards on the Mac and PC (SVGA)
use 8-bit D-to-A for each primary colour.

Digital RGB monitors cannot be used with an Analog RGB signal (unless
comparators are used to generate a digital signal from the analog one).

Analog RGB monitors cannot normally be used with a Digital RGB signal, but
generating an analog signal is possible with a resistor network (an example of
this is given in the Apple III Owner's Guide).  In some cases, it may be
possible to plug an Analog RGB monitor into a Digital RGB output, but it won't
produce the correct colours (when compared with a Digital RGB monitor).

There are two common types of digital RGB monitor: one type will work with the
Apple III, Apple IIe (with RGB card), Apple IIc (with RGB adapter) and CGA on
an IBM PC (different cables or adapters are required).  This type has intensity
and one bit each for red, green and blue (16 colours in total).

The second type is usable with EGA.  This has two bits each for red, green and
blue (64 colours in total).  These monitors also have a higher scan frequency
than the first type, and cannot be used with an Apple II (unless a card has
been specially designed to use them).

Analog RGB monitors are mainly classified by the scan frequency and resolution.
The IIgs RGB monitor (A2M6014X) operates at similar frequencies to television -
around 15 kHz.  Macintosh and VGA/SVGA RGB monitors do not support such low
scan rates, and typically work at about 30 kHz or higher.  The Mac cannot use
the IIgs RGB monitor, and the IIgs cannot use Mac/VGA RGB monitors.

Some third-party multisync monitors will work on the Mac/VGA and IIgs, but
these are very rare now.  Most multisyncs do not go as low as 15 kHz.

"15 kHz" and "30 kHz" refers to the horizontal scan frequency - Apple II video
output has a horizontal retrace roughly 15,000 times per second.

Vertical retrace is a different issue (it is much slower - usually 50 to 100
retraces per second), and most monitors are very flexible in the supported
vertical retrace rate, as far as I know.

This is also where "interlacing" comes in.  Interlacing is a technique which
doubles the effective vertical resolution of the monitor, by performing two
vertical scans (fields) per frame, with a slight vertical shift in the second
field.  The scan lines for the second field are interleaved between the scan
lines for the first field.

An interlaced display has more noticeable flicker than a non-interlaced display
with double the frame rate, because the phosphor is only lit half as often.

For example, the Second Sight card will support a 400 line interlaced mode with
the IIgs RGB monitor.  There will probably be noticeable flicker in this mode
(especially out of the corner of your eye).

This mode will have 60 fields (i.e. 30 frames) per second, whereas the standard
IIgs video output is non-interlaced with 60 frames per second (but only 200
lines vertical resolution).

(I'm assuming 60 Hz mode - the IIgs also support 50 Hz mode, for use in
countries with 50 Hz mains supplies and TVs.)

Television also uses interlacing - with NTSC, there are 525 lines per
interlaced frame and 30 frames per second, with alternating lines being scanned
on each pass of the electron beam (262.5 lines per field, 60 fields per

PAL uses 625 lines per frame, usually at 25 frames per second (312.5 lines per
field, 50 fields per second).


From: Rubywand

025- Can I replace my GS RGB monitor with one from a PC?

     Modern PC monitors generally have a Horizontal scan rate which is too high to
be compatible with the GS.  For some replacement options, see Q&A 015 above.


026- What are the specs and pinout for the GS RGB monitor?

Max Resolution:    640 Horizontal dots x 200 Vertical dots/lines
Dot Pitch:         .37mm
CRT Size:          12"/  11.5" viewable
Video Bandwidth:   6.5MHz   (+/- 1.5DB)

Scanning Frequencies

               60Hz model            50Hz model
Horizontal:    15.734kHz             15.696kHz
Vertical:         60Hz                  50Hz

 Pin    Function

  1     Red video ground
  2     Red composite video
  3     Composite sync
  4    (not used)
  5     Green composite video
  6     Green video ground
  7    (not used)
  8    (not used)
  9     Blue composite video
 10    (not used)
 11    (not used)
 12    (not used)
 13     Blue video ground
 14    (not used)
 15    (not used)
Shell   Shield ground


From: Mitchell Spector

    The above specs show only maximum resolution when used with a plain Apple
IIgs. It has an interlaced mode which allows you to display 640x400, though it
isn't going to be easy to look at for long periods of time. You can see the
interlaced mode if you have a VOC or Second Sight card.

    The viewable area on an Apple IIgs is probably a fair bit less than 12"/
11.5" viewable when you take into account all the space reserved by the border
in all display modes. That probably makes it about 10" viewable or so. If you
hook up another video source (e.g. a SuperNintendo) then you can use the entire
11.5", including what would be the border area.


From: Rubywand

027- Do I need to connect a monochrome monitor to my IIe to get
     readable 80-column text?

     Maybe not. Try turning down the "Color" control to get a B/W display and
adjusting Brightness and Contrast. This will, possibly, make 80-column text
readable on your composite color monitor. Just how readable will depend upon
the particular monitor. On the popular Amdek Color-1, readability is marginal
at best. According to some user reports, readability is decent on Apple's
composite color monitor.


From: Michael J. Mahon

Regarding the above ...

First, turning down the color control will do nothing to increase the bandwidth
of the luminance circuits, so the improvement in detail will be negligible.
The only possible improvement is from decreasing any additional blur from the
low bandwidth chroma signal.

Second, it is not just "some user reports" that the AppleColor //e and //c
Composite monitor is fully 80-column-capable.  This is a very special monitor
which switches the the luminance channel to high bandwidth when the color killer
is on, or when the "monochrome" switch on its front panel is pressed.

Of course, there is still a shadow mask, so the characters are not as "fully
formed" as with a pure monochrome monitor, but the monochrome resolution is good
enough to make it the only monitor required on even a "mostly text" machine.

To my knowledge, there are no other composite color monitors that have this
feature. I think it deserves some credit!


From: Jim Krych (ab453@cleveland.Freenet.Edu)

028- Is there a high-quality replacement for RGB monitors?

     Yes. It's called the "VideoTurtle." (What follows comes from a Video
Turtle advertisement.)

     The VideoTurtle is a product that converts your RGB signal, known as TV
RGB-15.75KHz scan rate for NTSC, into S-Video!  S-Video is an enhanced form
of TV with better clarity and resolution than the "TV" we are all familiar with.

     With your computer, the VideoTurtle, and an S-Video equipped TV, you get
equal or better display quality, than your old RGB monitor. Not only that, you
get a much bigger and eye-pleasing display, and a TV to boot!

     The VideoTurtle, from Turtle Enterprises, can be purchased for $149.95
from one of it's authorized distributors, such as Tex Comp Ltd. To order all
1-800-846-3474. For technical information on TV RGB systems we haven't
mentioned, or general technical help, call 1-626-967-3341. Turtle Enterprises
can be reached via email: videoturtle@hotmail.com


From: Tony Cianfaglione

029- Can I use a GS RGB monitor with my IIc?

     In mid-1980's, a company called Video 7 (which made video accessories
for various computer platforms) created the Video 7 RGB adapter for the IIc.
They also released a Video 7 RGB card for the II/II+/IIe.

     Two for-IIc versions were produced. The digital box is an L-shaped module.
It looks like a larger version of the RF modulator available for the IIc; and,
it plugs into the video expansion port on the back of the IIc/IIc+. It includes
a composite output to compensate for the one it covers as the module is quite
large. This box outputs 16 colours (all correct) on a TTL digital monitor like
the old NEC 2D and MultiSync II monitors via a 9 pin cable. (A Commodore
C128 RGB cable can be used for this purpose.)

     The analog box is about 2"x4"x1". It  outputs 8 colours (2 incorrect) which
can be used by a GS colour monitor.

     The text output from both boxes is switchable via 4 dip switches and can
change the text colour to red, blue, green and white. The analog box sits about
2" away from the IIc and connects via a 15-pin ribbon cable.  The GS monitor
cable plugs right into this adapter. Both boxes came with manuals as well as
demonstration software that put the adapters into various modes for IIc users.


From: Rubywand

030- I connected a composite monitor to my GS at the standard "RCA
     plug" output but I get a fuzzy dim display. The monitor worked
     fine on my II+. What's the problem?

     When a composite monitor is known to be okay, a fuzzy/dim display usually
indicates that the video output level is too low. (A too-bright, whitish, faded
look could indicate the output is too high.)

     You can adjust video output on a II+ via the small on-motherboard knob near
the Game I/O socket. There does not seem to be any way to adjust composite
video output on the GS. If your monitor has a video input level adjustment, try
changing the setting.


031- Ever since adding a SecondSight video board it seems like my
     GS is always crashing. Is the SS board causing problems?

     SecondSight adds some nice features; but, it is known to be a power hog.
Most likely, your system is crashing due to noise glitches on the +5V and/or
+12V power busses. The fix is to fatten power supply leads and, probably, add
on-motherboard +5V and +12V jumpers to a couple Slots. Details are supplied in


From: James D. Keim

032- My SecondSight board bombs every time I try to run Inwords or
     PublishIt. What's wrong?

     Inwords and PublishIt use the DHR display. The SecondSight cannot emulate
the DHR display and locks up the system.


From: Eric Jacobs

033- Including the left and right borders, how many dots are
     actually sent per line in 320 and 640 modes on the GS?

     Including the left and right borders, plus the horizontal retrace, the
video sends out more than 320 or 640 "dots" before the screen begins scanning
the next line. Here's a quick summary of the Apple II video that's been used
throughout the whole series (assuming 60 Hz video here). It's a slightly
modified NTSC signal, though the differences are small enough for most monitors
to accomodate.

     Everything in the Apple II is derived from a 14.31818 MHz master clock.
This runs both the video and the processor/memory subsystems. The cycle time is
therefore 69.8 ns. For 640-mode (or 80 cols, or double-hires) the dots are sent
out at simply this rate. In 320-mode (40 cols or single-hires) the dots are
sent out at half that rate, 7.15909 MHz (one pixel every 139.6 ns). The NTSC
standard calls for 227.5 cycles of color reference (3.579545 MHz) per
horizontal line, for a horizontal scan rate of 15.734 KHz (3.579545/.2275). The
Apple II rounds this up to 228 cycles of 3M, so the horizontal scan rate is
15.699 KHz (3.579545/.228). This is well within the tolerance of most monitors.
So therefore in 320-mode 228*2 = 456 "dots". In 640-mode there are 912 "dots".
I put dots in quotes because, obviously, only 320 or 640 of them are actually
seen as part of the screen.

     When the GS is outputting a composite video signal, each horizontal line
must contain a horizontal sync pulse and color burst, and there can't be a
border during this time, or else the TV won't register a sync. On the RGB, the
GS puts the border color on. So, the answer to your question is 456-320 or 136
pixels in 320-mode and 912-640 or 272 pixels in 640-mode. This includes both
borders and the horizontal sync. Of course, a good proportion of this time is
not visible; this depends on the overscan settings of the particular monitor.


From: Eric Jacobs

034- I picked up a IIgs RGB monitor at a garage sale. The focus is
     off and it took several minutes until the display got brighter
     but it's still not very good. Are there any adjustments that can
     be made?

     The problem you describe is consistant with low B+ going to the flyback
transformer which results in low brightness level, poor focus, and blooming
when the brightness and/or screen level is turned up. More than likely if this
monitor has been sitting around for awhile, the filter capacitors have gone to
mush. Sometimes they can be revived by leaving the monitor on for a long period
of time <over 24hrs> but, usually, they require replacement.


From: Wayne Stewart

035- Where can I get a GS RGB monitor cable?

     You can try a store selling Mac supplies and get a Mac 15 pin cable. I'm using
one right now where I needed a longer than standard cable


From: John J and Tim

036- Can I replace my Apple II composite monitor with a PC VGA monitor?

     Yes; you can use a VGA-Box (or "V-Box"). It accepts 4 composite video inputs
(NTSC or PAL) and 1 VGA input.  The output is VGA.

     Briefly VGA-Box converts your Apple II video (from the RCA plug) to a 15-pin
VGA/SVGA output you can plug it into a modern PC monitor.

     VGA Box  is priced under $50. For a pic and ordering info, see
http://store.yahoo.com/baysoftgames/vgabox1.html .

     I was using an old monochrome monitor. Finally I can play all my games in color
once again!


From: Stephen Shaw

037- My IIGS monitor works for about half an hour, then the screen goes
     blank, and the power light goes out. Pressing the power button has
     no effect.

     Disconnect the monitor, remove the AC power cord, and open up the case.
Warning: High voltages are present! For case opening directions, safety tips, and tool
info, see Q&A 003-006 above.

     The power supply has about five components one of which is a big white ceramic
resistor (3.3 ohms in the 110V colour monitor). You will probably find that the solder
connecting this resistor has crystallized.

     Unsolder the resistor, scrape the leads with a Stanley knife (gently!). Clean the
solder pads with some 200 grit wet and dry sandpaper. Resolder the resistor and

     If the resistor is OK. Then check the "kickstart" cap in the power supply (by
swapping in a substitute). You can also check the STKxxxx power supply chip for
bad solder joints.

Good luck!


From: Rubywand

038- When I play old hires games on my GS the RGB monitor display
     does not look as good as my old Amdek Color-1 connected to
     the II+. What's wrong?

     Most hires displays look better on a composite color monitor, such as the
Amdek Color-1, than they do on the GS's RGB monitor. The difference is even
more striking for double-hires displays. (King's Quest and Air Heart look much
better on a Color-1 connected to a IIc+ than on an RGB monitor connected to
the GS.)

     What's wrong is that the GS's display circuits do just a passable job of
translating hires and double-hires into RGB form.