Apple II comp.sys.apple2 FAQs 7/18/1998 HARDWARE HACKING

[Rubywand <rubywand@swbell.net>]

Apple II Misc Hardware Hacking

Csa2 FAQs-on-Ground file: CSA2HDWHACK.TXT  rev006


The Csa2 (comp.sys.apple2) usenet newsgroup Frequently Asked
 Questions files are compiled by the Ground Apple II site,
 1997, 1998.

ftp://ground.isca.uiowa.edu/2/apple2/Faqs
http://ground.isca.uiowa.edu/2/apple2/Faqs

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 001- What's a good hardware project book for the Apple IIe?
 002- How can I use a thermistor to read temperature on my A2?
 003- Will a prototyping Slot Board fit all Apple II's with Slots?
 004- What is the pin-out for the Apple II series Slots? 
 005- I've been getting Fatal System Error 0911. Is there a fix?
 006- Why does my GS Control Panel keep resetting to the defaults? 
 007- How do I replace my GS "BatRAM" battery?
 008- Is there a program to record/restore Control Panel settings?
 009- How I can safely clean out dust from my Apple II?
 010- How can I safely remove oxidation from IC pins? 
 011- After smoke came from my GS the KB doesn't work. What's wrong?
 012- What is the mini circuit board near the front of my GS for?
 013- How do I add memory to my 1MB Apple IIgs Memory Expansion Card?
 014- How can I move my IIgs to a PC tower case?
 015- How can I convert a IIgs into a portable IIgs?
 016- Where can I get Robot kits to use with my Apple II?
 017- Where can I get the chips to expand memory on my AE GS-RAM III?
 018- What is a TrackStar? Does it need special software?
 019- Could someone please post a resistor color code chart?






From: Paul Guertin

001- Could anyone suggest a good project book for the Apple IIe.
     I'm interested in using an old box for tracking the
     temperature in a water bath.


Vernier software publishes a book called "How to Build a Better
Mousetrap" which contains 14 hardware projects for the Apple II. Project
#6 is a temperature probe connected to PDL0.

ISBN for the book is 0-918731-16-X.
Vernier Software ( http://www.vernier.com )  
2920 S.W. 89th Street
Portland, Oregon  97225 USA
(503) 297-5317

----------------------------


From: Sheldon Simms

A good book is _Inside The Apple IIe_ by Gary B. Little. It isn't a
project book, but it does have a good chapter on using the Game I/O
connector for "electronics experiments."


____________________________



From: Cyrus Roton

002- How can I use a thermistor (a resistor which has a variable
     resistance related to ambient temperature)  to read temperature
     on my Apple II?


You can connect a thermistor to a paddle input and supply a voltage to
the other end. Current flows through the thermistor to charge a .022 mfd
capacitor inside the apple2. When the paddle is read, the apple2
discharges the capacitor and resets a timmer. Then the cap is allowed to
charge. When the charge reaches the trigger level (3.2 volts) the timmer
is stopped and the count is read out.

The lower the value of the thermistor, the faster the charge and the
lower the count. Also, the higher the voltage, the faster the charge.  A
resistance of about 120K with a 5 Volt supply will give a count of about
250. You can add an external capacitor across the paddle input (to
ground) to increase the charging time (if needed)

 The formula is (charge) = (input volts) * (1 - exp(-t/RC))

So, you can use a supply voltage and external capitor as required to fit
the resistance value of the thermister (or other resistive component).
Probably, the best way to find the correct values woud be to try a
variety of values and plot the "count" as a function of the variable
resistance. Then compare the plot against the resistance curves for the
thermistor (probably not linear), and work out some conversion formula
to use in your program to correlate "count" to temperature.


____________________________



From: David Empson

003- Can I use the same prototyping Slot Board for all of the
     different Apple II's with Slots?

Prototyping boards certainly would be the same for the II, II+, IIe, and
IIgs. The slots on all slotted Apple IIs are physically identical

There are minor differences between the slot signals on the various
machines and on some slots in the same machine, mostly affecting rarely
used special pins. (See Question 004 for more details on signal
differences.)

----------------------------


004- What is the pin-out for the Apple II series Slots; and, what
     differences are there in Slot signals from machine to machine?
 
Here is a quick summary of the Apple II series Slot signals:

Pin 1: I/O Select ($Cn00-$CnFF, where n is the slot number).

Pins 2-17: Address bus A0-A15.

Pin 18: Read/Write.

Pin 19: unused on the II and II+.  On the IIe and IIgs, this has
composite horizontal and vertical sync on slot 7, and is unused on other
slots, except for slot 1 on the IIe only, which has a diagnostic
function to disable the oscillator on the motherboard.

Pin 20: I/O Strobe ($C800-$CFFF).

Pin 21: this is the RDY input to the micro on all machines, but it
behaves a little differently in the IIgs, or in a machine with a 65802
installed.

Pin 22: this is the DMA pin on all machines.  Again, there are special
issues for doing DMA on the IIgs which can cause compatibility problems.

Pin 23: this is used for the interrupt daisy chain (out) on all Slots
except 7. In the IIe only, this pin can be connected to the GR signal
(graphics mode enabled) via a motherboard modificatoin.

Pin 24: DMA daisy chain out.

Pin 25: +5V.

Pin 26: Ground.

Pin 27: DMA daisy chain in.

Pin 28: Interrupt daisy chain in.

Pin 29: Non Maskable Interrupt.

Pin 30: Interrupt Request.

Pin 31: Reset.

Pin 32: this is the INHIBIT pin on all machines.  This behaves
differently on all three machines: the II and II+ only allow the
$D000-$FFFF ROM area to be inhibited.  The IIe allows RAM to be
inhibited as well, but has strange interaction with main and auxiliary
memory.  The IIgs only allows this signal to be used if the machine is
running in slow mode.

Pin 33: -12V.

Pin 34: -5V.

Pin 35: unused on the II and II+.  On the IIe and IIgs, this is the
colour reference signal on slot 7 only.  It is unused for other slots in
the IIe, except for slot 1 where it provides a poorly documented
facility to disable the keyboard address decoding.  On the original
IIgs, slot 3 provides the M2B0 signal (Mega II Bank 0) via this pin and
it is unused on other slots.  The ROM 3 provides M2B0 for slots 1 to 6.

Pin 36: 7 MHz system clock.

Pin 37: Q3 - Asymmetrical 2 MHz clock.

Pin 38: Phase 1 clock (1.023 MHz).

Pin 39: something called "USER 1" on the II and II+, which can be used
to disable all I/O decoding if a modification is made on the
motherboard.  On the IIe, this pin provides the SYNC signal from the
micro, which indicates an opcode fetch.  On the IIgs, this pin provides
the M2SEL signal, which indicates that a valid slow memory access is in
progress.  This pin must be used by IIgs cards that decode the address
without use of the IOSEL, IOSTRB or DEVSEL pins.

Pin 40: Phase 0 clock (1.023 MHz).

Pin 41: Device Select ($C0n0-$C0nF, where n is the slot number plus 8).

Pins 42-49: Data bus D7-D0.

Pin 50: +12V.

____________________________



from Rubywand

005- I've been getting Fatal System Error 0911 and when I do the
     internal diagnostic it gives a system bad : 09010001.
     Is there a fix?

     Fatal System Error 0911 and Self-Diagnostic Test 09010001 mean the
same thing: You are, very likely, experiencing an ADB Controller
malfunction.

     A guess would be that you are running a ROM-01 GS, probably a
ROM-00 machine which has the ROM-01 upgrade. If this is the first time
you've noticed the '0911 problem, it is likely that this is the first
summer you've owned and used this particular machine.

     Many early GS's come with an ADB IC which malfunctions over a
narrow range of relatively low temperatures. Rooms are normally cooler
during summer; so, this is when the error pops up most frequently. Some
users first notice a plague of '0911 crashes after adding a System
Saver-GS (which increases cooling).

    '0911 bombs can occur 'any time' but they usually happen at startup
and when doing OpenApple-CTRL-ESC accesses to the Desk Accessories
(CDA's, Control Panel, ...) menu. As the machine warms up, '0911 crashes
tend to become less likely.
 
     The bad news is that there is no 100% fix except to replace the
temp sensitive ADB IC-- hard to do since it is soldered to the
motherboard and, in any case, known-good replacements are difficult to
find.

     As to _which_ ADB IC-- there are two, the ADB Controller and the
ADB GLU-- our notes say the ADB Controller; but, we could have easily
misidentified the function back then and the ADB GLU IC 'clicks' better
with memories of the fix. (The ADB GLU IC is a bit larger and easier to
reach.)

Note: The easiest way to identify the temp sensitive IC is to apply the
fix (below) and see if it works. If it does, fine. If not, it is easy to
move the fix to the other IC. For now, my suggestion is to try the ADB
GLU IC first.

     Since the problem is coolness, a decent cure is to tape a small 12V
bulb (e.g. a 20-30 ma. panel light bulb) to the top of the ADB IC (a
square IC near the right front of the motherboard). Use duct tape and
try to enclose the bulb and IC in a kind of mini-oven. Run the leads
from the bulb to the +12V Fan power pins near the back left area of the
motherboard.

     The idea is to quickly warm up the IC. I used a scheme like this on
our early GS and 0911 bombs dropped from 4-5 per day to 2-3 per week. If
you can safely power the bulb via an external power module (e.g. a
calculator or radio 'AC adapter') so that the bulb can be ON at least a
few minutes before powering up the computer, 0911 bombs might disappear
entirely.

----------------------------


006- My GS control panel keeps resetting to the defaults and
     forgetting the date between power-ups. What's wrong?

     Most likely, your battery-- also called the "BatRAM  battery" needs
to be replaced.  When the GS is OFF, the battery supplies power to the
clock and its attached 256-byte RAM. This small RAM is where Control
Panel settings are 'remembered'.

     If, upon power-up, the GS believes the Control Panel settings have
been messed up due to a low battery, it will reset the settings to their
default (check-marked) positions.

----------------------------


007- How do I replace my GS "BatRAM battery"?

     The standard GS battery is a 3.6V Lithium type rated at 1.2AH. It
is called the "BatRAM" battery because it keeps the Battery RAM and
Clock IC going when you turn OFF power. To get to the battery, you must
pop out the Power Supply.

     If you have a ROM 03 GS, you can slip out the old battery and slip
in 'one like it'. On the ROM 01 GS, you will need a Lithium battery with
leads you can connect to cut-off leads from the old battery-- about 3/4"
each-- remaining on the motherboard. Be sure to mark the "+" lead on the
motherboard with white-out.

     Night Owl Productions used to sell a convenient "Slide-On" Lithium
battery made by Tadiran. It came with springy ends that would slip over
the cut-off leads from the original GS battery.

     Radio Shack sells a few models of 3.6V Tadiran Lithium batteries.
Mostly, these have smooth ends and are intended to fit into a holder--
for example, one model is "AA" size. Connecting an insulated size AA
holder and using a size AA 3.6V battery is one way to handle BatRAM
replacement now while making future replacements easier.

     Another Radio Shack 3.6V Tadiran Lithium battery comes as a small
rectangular insulated pack with red and black wires going to a plug.