Apple II Accelerators

Csa2 FAQs-on-Ground file: Csa2ACCEL.txt  rev012

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 001- What are the correct settings for a ZipGS? 
 002- Why should Appletalk Delay be disabled with a ZipGS?
 003- How do I set up a Transwarp on my IIe?
 004- Is there a way of disabling Transwarp for games?
 005- What are specs & jumper settings for a vintage SpeeDemon?  
 006- How does the SpeeDemon rate as an accelerator? 
 007- My SpeeDemon accelerator board seems to run hot. A fix? 
 008- How should the DIP switches be set on a v3.03 SpeeDemon?
 009- How can I get a 'Cache Hit' indicator for my ZipGS?
 010- How can I program the ZipGS registers?
 011- How can I set up a ProDOS sys file to turn my ZipGS OFF/ON?
 012- Is there some ZipGS mod that will improve performance? 
 013- I have a 7MHz ZipGS. How fast can the board be pushed?
 014- What Oscillator freq corresponds to what upgrade speed?
 015- How do I experiment with different oscillator frequencies?
 016- How do I modify my ZipGS to accept the new "skinny" RAM chips?
 017- Is it really necessary to increase board voltage 
 018- What kind of performance increase can I expect?
 019- How can I modify my ZipGS for more cache and more speed?
 020- Do I need new GALs to speed up my TransWarpGS?
 021- How does a TWGS cache upgrade compare with a speed upgrade?
 022- How can I upgrade my TWGS to 32k cache?
 023- How can I upgrade TWGS speed?
 024- What kind of RAMs do I need for a TWGS or ZipGS speedup?
 025- How can I tell the firmware version of my TWGS?
 026- For my TWGS, do I need the 2B GAL to use a SCSI interface card? 
 027- Why are my ZipGS settings via the Zip CDA forgotten? 
 028- What do the check-marks mean in the ZipGS CDA?
 029- Why don't my ZipGS settings match DIP switch settings!?
 030- I have a ZipGS. Sometimes my GS 'hangs' on power-up. Why?
 031- The speedup has led to system crashes. What's the problem?
 032- A new accelerator board has led to crashes. What's the problem?

From: Marc Sira

001- What are the correct settings for a ZipGSx? I've tinkered
     with "CPS Follow", "Counter Delay" and the like but have
     no idea what I'm actually doing.

CPS Follow should always be enabled. If you disable it you will have
problems with Disk ]['s and System 6's AppleTalk driver and anything
else that expects the Zip to slow down to 1 mhz when the GS is
instructed to slow down to 1mhz. For instance, border text demos (like
the FTA XMAS demo) won't work if you have this disabled. Expect weird
things to happen if you play with this one.

Counter Delay I would recommend leaving enabled. This causes the Zip to
"deaccelerate" (actually all it does is temporarily ignore that any data
can be read from the cache instead of the motherboard) for about 5
milliseconds any time you read one of the Video Counters -- this is
really only there so that one of the self-tests will pass. Which way you
set it shouldn't be fatal.

AppleTalk or Interrupt Delay should always be disabled. The desktop will
run much slower if you enable it. The only reason most people needed it
was for AppleTalk under system 5, and I have an init on tybalt that
fixes that. System 6 fixed the problem but requires CPS Follow to be
enabled for the fix to work.

Speaker and Paddle delays are intended to let old 1-bit sounds and
Paddle access work the way they do on an unaccelerated IIgs. I recommend
leaving these on unless you feel like experimenting. They shouldn't be
fatal but some program might react very negatively, so be prepared.

Bank C/D cache enable -- leave this at the default setting and forget
about it. This tells the Zip if it's OK to cache bank-switched RAM (the
old language card area). Zip's own docs say "there is no know software
requiring this" but that it why it's there, in case somebody ever finds
software that doesn't like it you can try setting it the other way.


From: Todd P. Whitesel

002- Why should Appletalk Delay be disabled with a ZipGS?

Because it saps performance every time an interrupt occurs.

The Appletalk delay was originally called the "Interrupt Delay" but they
renamed it at the last minute because somebody actually tried an 8/64 on
an Appleshare network and it dropped packets like crazy.

With "Appletalk delay" on, every time an interrupt occurs your Zip will
disable acceleration for 5 ms, just like it does with the paddles and
the speaker and the others. This is a significant effect because with
VBL interrupts going you have one every 16 ms, so your Zip spends nearly
1/3 of the time not accelerating you.

Why this "fixes" appletalk: in system 5 and earlier (including the ROM
appletalk code), there are software timing loops which assume 2.8 mhz
operation. As you speed the system up, it gets more and more likely to
drop incoming packets because it thinks they are being sent too slowly
to be correct, when in reality the appletalk code is timing out too

Why the Appletalk delay is not a complete solution: a full-size
Appletalk packet that you'd get from a file server takes about 14 ms to
transmit. The Appletalk delay covers the first 1/3 of the packet, the
VBL interrupt covers at most another third of the packet, but nothing is
guaranteed to keep acceleration off for the whole packet. If you speed
the Zip up more, say to 10/64, it starts dropping long packets no matter

This latter problem was why I originally wrote ZipTalk. It required a
slot delay to be enabled (in, say, slot 6 or 7), and before each
appletalk packet was received I tweaked that slot -- slot delays are 50
ms, so the Zip stays unaccelerated way past the end of the packet and
everything works. (I also patched packet sending, to be safe.)

In system 6 Apple fixed things correctly in the appletalk drivers. I
removed the code from ZipTalk and released what remained as ZipFix. As
of 6.0.1, the cursor flicker problem was fixed by apple in the control
panel, so now you only need ZipFix for the GS/OS SET_SYS_SPEED hook,
which nobody seems to use.


From: Jeff Brielmaier

003- How do I set up a Transwarp on my IIe?

Bank1: Sw 1-7 -> Change to OPEN if there is a memory card that uses the
"Langauge Card bank switching technique". (Normally CLOSED)

Bank1: Sw 1-7 -> Change to OPEN if the plug in card must be accessed at
1 MHz (Normally CLOSED.  OPEN for Floppy diskette controllers)

Switch 8 on both Banks: Sets the power up speed of Transwarp

           Bank1   Bank2

3.6 MHz     OPEN    OPEN  <<Normal>>
1.7 MHz   CLOSED    OPEN
1   MHz     OPEN  CLOSED


004- Is there a way of disabling Transwarp for games?

Press <Esc> at power-up will disable Transwarp completely until the next
power off/on cycle.

A better way is to write a 01 to $C074.  This will slow Transwarp down
to 1 MHz without disabling it completely.  Writing a 00 to $C074 will
restore Transwarp to it's 'fast' speed.


From: Rubywand

005- I recently bought an "M-c-T SpeeDemon" board. It's dated 1984
     and draws a small apple on the screen after power-up. What kind
     of cache RAM does it have? There's a place for jumpers near the
     top of the card. Is there a way to control this thing through
     software or hardware?

     Your card may be a slightly later model. (I've never noticed ours
draw a hires apple on the screen-- darn it!)  Possibly, McT came out
with a revision aimed at 128K IIe's.

     The RAMs on our vintage model SpeeDemon are 100ns 2048x8 9128's
(for a total 8K of pretty speedy cache).

     I once asked McT about the jumper block you mention, they said the
jumper is set at the factory to adjust on-card timing and to Leave It
Alone. (On our card, the jumper block has 5 pairs. The pair 2nd from the
top is jumpered.)

     There is also a jumper pair near the bottom middle of the card.
This is the Speed Jumper. Jumper it if you want 'demon to slow down for
I/O accesses to Slots 4 & 5. (The 'demon always slows for Slot 6 I/O
($C0E0 - $C0EF.)

     According to the "Manual" (a folded card),  pressing PDL-1
(Closed-Apple on a IIe) upon power-up will engage a self-test. Pressing
ESC at power-up will turn OFF the card and allow running at normal
speed. To turn OFF the card later on, do a POKE (49152+256*S) where S=
Slot # of the slot the card is in; then, press RESET.

     You can put the 'demon into any Slot; but, if you put it in Slot 0
(Slot 3 in a IIe), the card will not respond to any KB shut-off


006- How does the SpeeDemon rate as an accelerator for II+
     and IIe Apples?

     In terms of raw performance (once you arrange for cooling),
SpeeDemon may be the best of the 4MHz accelerators for early II's. I've
never noticed any compatibility problems and the approx. X3.5 speed
increase puts real 'snap' into your machine's response. (Besides, it's
great for games like Elite!)


007- My SpeeDemon accelerator board seems to run hot in my II+.
     Is this normal? Should I add cooling?

     Indeed, the 'demon is a power gobbler-- roughly 1.5A as I recall--
and some of the IC's run hot. When the board bombed after one long
session, we cut out a square section on the back of the II+ and added a
mini-fan, just to blow air across the 'Demon board. This ended the heat


From: Douglas M. Howell

008- How should the DIP switches be set on a version 3.03
     SpeeDemon board?

This is from the 1-page manual that comes with the card:

    For owners without a Bank Switch Language Card in thier Apple, the
first seven DIP switches control the access speed of the following:

      switch 1 -- controls -- slot 1
      switch 2 --    "     -- slot 2
      switch 3 --    "     -- slot 3
      switch 4 --    "     -- paddle/joystick port
      switch 5 --    "     -- slot 5
      switch 6 --    "     -- slot 6
      switch 7 --    "     -- slot 7

OFF indicates slot/port is accessed at High Speed.
ON indicates slot/port is to Slow Down for access.

     All slots that can be accessed at High Speed and all empty slots
should have the corresponding Dip switch set to "OFF" (this is the
non-bank switch setting).

Special Note about Switch 4:

     Switch 4 on the SpeeDemon DIP switch no longer controlsthe access
speed to slot 4. It now controls how the joystick and paddles are read.

     If switch 4 is in the "ON" position, the SpeeDemon will slow down
to normal Apple speed for 50 milliseconds each time the joystick is
accessed. This allows the software to read the joystick or paddles
correctly. If switch 4 is in the "OFF" position, the SpeeDemon will not
slow down when they are accessed.

     Access to slot 4 is always at SLOW (normal) Apple speed.

     Certain programs, such as Appleworks, use the joystick location,
even when the joystick is not in use.  If dip switch 4 is set to "ON"
then these programs will not show any speed for some functions, such as
calculations and sorts. Therefor, unless you need youysticks for your
applications, switch 4 should be set in the "OFF" position.

     If you have a Bank Switch Card (extended 80-col card, Ramworks II,
Titan Saturn 128k card, excetera..) set switch 8 to the "ON" position.

Bank Switch Language Card Location:

   Dip Switches 1-3 encode the location of your Bank switch language
card. Use the following table to find the appropriate setting for your

      Dip Switch   Bank Switch Card Location

      1   2   3    Slot #
     --- --- ---   ------
     off off off     0
     off off on      1
     off on  off     2
     off on  on      3
     on  off off     4
     on  off on      5
     on  on  off     6
     on  on  on      7

If you have two bank switch cards in your system, one must reside in
slot 0. The other must be in the slot selected by DIP switches 1-3

   Special Note: Because the first three switches are used to encode the
location of the Bank Switch Language Card, you can no longer control the
speed of all the slots.  Specifically you can not control slots 1,3, or
6. These slots woll now always run Fast except for slot 6 which will
always run Slow.

   Special Note: The slot that the SpeeDemon card resides in should be
set to the "Off" position


From: Will Baguhn

009- How can I get a 'Cache Hit' indicator for my ZipGSx?

This latest ZipGSx modification is pretty straightforward. When I
decided I wanted a Cache HIT light instead of a Cache MISS light, I went
to Rat Shack and bought a pack of Green LEDs (I like green. Blue or
Orange will work just as well.)

I tried adding an inverter to the circuit but it just didn't want to
play (obviously a cache HIT is the opposite of a cache MISS, and the LED
on the board lights up for cache MISSes).  Through the experimenting, I
found that I could get the LED to light as desired without any "extra"
hardware except the LED itself.

Simple mod:  solder in the Anode of the LED to the Anode of the Cache
Miss. Solder the Cathode to the Cathode of the Power LED.

(Even easier way to say it: there are four solder points for the
existing LEDs. We use the two in the middle.  The long lead goes to the
yellow side, the short to the red.  position as is comfortable.  I can
only guess that this would be a nice thing to attach to the TURBO light
on the front of a tower case, should anyone ever mount a IIgs/ZipGSX
inside a tower case... (also, it might be nice to turn SW1-6 OFF and
connect the pins to the TURBO button on front.  I don't know how useful
it would be, but it might come in handy one of these days...)


From: David Empson

010- How can I program the ZipGSx registers?

ZipChip GS Special Registers   Ex ZIP Technology, 12 October 1990

Registers must be unlocked before they can be accessed (see $C05A). 
Locking them will re-enable the annunciators.

Writing to any I/O location $C058-$C05F (whether registers are locked or
unlocked) will reset delay in progress.

$C058 R   No operation

$C058 W   Write any value to force power-on/reset bit to COLD (forces
next reset to restore ZIP registers to defaults/switch settings).

$C059 R/W 76543210
          *.......  Bank Switch Lang Card cache disable=1/enable=0?
          .*......  Padl delay (5 ms) disable=0/enable=1 $C070/$C020
          ..*.....  External delay (5 ms) disable=0/enable=1
          ...*....  Cntr delay (5 ms) disable=0/enable=1 $C02E/$C07E
          ....*...  CPS follow disable=0/enable=1
          .....*..  Last Reset warm?              READ ONLY
          ......*.  Hardware DMA                  READ ONLY
          .......*  non-GS (0)/GS (1)             READ ONLY

$C05A R   76543210
          ****....  Current ZIP Speed, 0=100%, 1=93.75%,..., F=6.25%

$C05A W   Write values as follows:
          $5x       Unlock ZIP registers (must write 4 times)
          $Ax       Lock ZIP registers
          other     Force ZIP to follow system clock (disable card)

$C05B R   76543210
          *.......  1msclk - clock with 1 ms period
          .*......  cshupd - Tag data at $C05F updated
                   (read $C05F to reset)
          ..*.....  Bank Switch Language Card cache (0), don't (1)
          ...*....  Board disable - 0=enabled, 1=disabled
          ....*...  delay in effect (0=ZIP, 1=Slow)
          .....*..  rombank (0/1) - not in development version
          ......**  Cache RAM size (00=8k, 01=16k, 10=32k, 11=64k)

$C05B W   Write any value to force ZIP to current speed
                   (i.e. enable card)

$C05C R/W 76543210
          *******.  Slot 7-1 delay enable (all slots 52-54 ms)
          .......*  Speaker delay enable (5 ms)

$C05D R   Current 65816 bank

$C05D W   76543210
          ****....  Set ZIP speed, 0=100%, 1=93.75%, ..., F=6.25%
          ....****  Don't care

$C05E R   Read last Tag data written and force the next write
          to create a trash tag value.

$C05E W   No operation

$C05F R   Read last Tag data written and reset cshupd.
          Note: apparently any write to a ZIP register
         (unlocked) will clear cshupd, but cshupd
          says that this location must be read.

$C05F W   No operation


011- Is it possible to set up a simple ProDOS-8 application
    (SYS) file which turns the ZipGS OFF or ON?

From the usual BASIC prompt, get into the Monitor (e.g. CALL -151) and
type in the following code to turn OFF the ZipGS ...

2000:A9 50 8D 5A C0 8D 5A C0 8D 5A C0 8D 5A C0 8E 5A
2010:C0 0A 8D 5A C0 20 00 BF 65 1D 20 00 00 04 00 00
2020:00 00 00 00 

A 2000L should look something like this ...

2000: A9 50    LDA  #$50
2002: 8D 5A C0 STA  $C05A     ; write $50 to $C05A four times to
2005: 8D 5A C0 STA  $C05A     ; enable access to the ZIP registers
2008: 8D 5A C0 STA  $C05A
200B: 8D 5A C0 STA  $C05A
200E: 8E 5A C0 STZ  $C05A     ; write $00 to $C05A to disable ZIP
2011: 0A       ASL                = SLOW mode
2012: 8D 5A C0 STA  $C05A     ; write $A0 to stop accessing ZIP
2015: 20 00 BF JSR  $BF00     ; Do a ProDOS QUIT call
2018: 65       $65
2019: 1D 20         $201D
201B: 00 00    BRK  $00
201D: 04 00 00 00 00 00 00

Use the following commands to save it:


To enable the ZipGS (= FAST mode), simply change one byte:


(this changes the STZ $C05A to STZ $C05B)



From: William Baguhn

Reference: FAQs resource file R005SPLITC.GIF (pic file)

012- Is there some ZipGSx mod that will improve performance
     without going to a faster crystal, etc.?

     There is; you can do the ZipGSx Split Cache Mod. As your manual
explains, Zip GSX speed comes from having a faster processor which can
access code and data from its high-speed cache RAM. The standard 'GSX
has a unified cache, which means data and code have the possibility of
overlapping. If the cache controller sees a need to bring in a lot of
code, it will go to main memory and bring in up to 64k of code (or 16k
in a 16k cache system) and, possibly, overwrite useful data.

     The reverse is also true. If the controller feels that a lot of
data needs to be brought in, it will cache the data, and, possibly,
overwrite useful code, causing another slowdown when the code needs to
be fetched again.

     With a split cache, the code and data segments no longer overlap.
Caching code cannot overwrite data, caching data cannot overwrite code.
The drawback is that only 32k of data and 32k of code can be cached at
once (in a 64k system), but usually this provides for more speed than
being able to cache a 64k mix of both.

     To do the mod, you'll need a ZipGSX version 1.02 with either 16k or
64k cache on it. If you're not sure exactly what board you have, it's
pretty straightforward to figure things out: open the computer and look
at the Zip. The board revision is silkscreened on just beneath the

     The cache size can be determined from the DIP switch settings.
However, a simpler guideline is look at the TAG/DATA sockets and count
the number of chips. If there are only 2 chips, you have either an 8k or
a 32k cache. If there are 4, then you should have 16k or 64k.

     To modify your Zip for the Split Cache, you'll need a good hobby
knife that can cut the traces without damaging the board underneath too
badly, as well as two or three small lengths of wire. You will also need
a good pencil-style soldering iron, desoldering pump or braid, and high
quality rosin core (NOT acid core) solder. I use Radio Shack's .032
60/40 rosin core solder. Kester makes excellent quality solder which is
sold at many electronics supply shops.

     There is a potential of damaging expensive and delicate hardware.
For example, when cutting a circuit trace be careful not to cut deeply,
lest you cut a trace in the next layer of the circuit board. If you're
not experienced with cutting traces or soldering on circuit boards, find
an old board and take some time to practice.

     The actual mod is very simple. Steps 1-3 and 5 are for all boards.
Step 4 is for 16k cache boards only. (Note: The picture in FAQs resource
file R005SPLITC may be helpful for doing these mods.)

1. Locate J6 and J7.  They are both blocks of 3 pinholes, which may or
may not have been soldered-in, near the bottom of the board next to
connector J1, where the gray cable attaches.

2. Cut the SMALL trace between pins 2 and 3 of both J6 and J7. This
trace is on the back (solder side) of the board.

3. Solder in a piece of wire between pins 1 and 3, of both J6 and J7. A
wire that has been bent into a U shape before soldering seems to work
best, both for ease of installation and aesthetic value.

4. 16k systems ONLY: (See the "16k" insert on the picture in FAQs
resource file R005SPLITC.)  Cut the trace between pins 1 and 2 of J8 on
the top side of the board.  (J8 is below the Cache SRAM sockets)  Then,
solder a piece of wire between pins 2 and 3 of J8.

5. Set the DIP switches appropriately. The DIP switches needing to be
set are SW1-7 and SW1-8, they control the cache size. SW1-7 should be
OFF for 64k, ON for 16k. SW1-8 should be ON.

     Reversing these changes is fairly easy. If you decide that the
performance change was detrimental, simply desolder the wires that you
installed, and solder in wires to replace the traces that were cut.

     I found that the split cache sped up my system notably, especially
under the Finder and other desktop applications. Improvement was much
less noticeable under text applications. (I haven't checked affect on
compiling speed, yet.)


From: Rubywand

     I tried the split-cache mod on my 10MHz/64kB ZipGSx. Before/after
timings were done for several tasks including Scrolls through Finder
windows, Scrolls and Find/Replace through Coolwriter (super-res) and
Appleworks (plain text) documents, and Platinum Paint fills.

     Timing differences were very small-- usually within the error
normally experienced when clicking a stopwatch for repetitions of
identical events. Where a difference was observable, it favored the
unified 64kB cache.

     Evidently, at least on a 64kB board, the ZipGS does a fairly good
job of managing the unified cache. Possibly, the mod comes out ahead in
some tasks not sampled; or, it may work better on 16kB boards.


From: Richard Der

013- I have a 7MHz ZipGS. How fast can the board be pushed without
     getting new SRAMs or a new CPU? What parts do I need?

     You may be able to get it to run at up to 10MHz by just replacing
the oscillator with a faster one for less than two dollars!

     I have a Zip GS that came as a 7/32 and was used at 7MHz for a long
time. The board came with a socketed oscillator, so one day I swapped
out the 28MHz oscillator for a 36MHz one. The computer booted up at
9MHz. When the 36MHz osc was replaced with a 40MHz osc, the Zip ran at
an amazing 10MHz!

     Your mileage may vary, though. The GS that this upgraded Zip
resides in has a high output power supply. Still, considering these
oscillators cost $1.39 each, it is worth getting three or four and
trying an oscillator swap alone first. If a faster oscillator alone
won't do the trick, then a faster CPU and/or faster cache chips may be

Good Luck!


From:  Frank M. Lin
014- What Oscillator freq corresponds to what TWGS/ZipGS
     operating speed?
     For TWGS and ZipGS, the crystal oscillators runs at 4 times the
speed of the 65816. Below is a chart showing osc and corresponding TWGS
or ZipGS speed.

Osc Frequency MHz      TWGS/ZipGS Speed MHz
     32                      8
     33.3333                 8.3333
     36                      9
     40                     10
     42                     10.5
     46                     11.5
     48                     12
     50                     12.5
     55                     13.75
     60                     15
     My understanding is that, if you over-clock a CPU. It just won't
function. You can't damage it. As the disclaimer said, do it at your own
risk. I have tried to run my TWGS at 20 MHz, system won't boot at all.
No damage.


015- How do I experiment with different oscillator frequencies? 
     Most of the following is from a piece on ZipGS upgrading by Long.
It is also a useful guide for TWGS owners. 

     The Zip can use three types of crystals including the common 4-pin
full TTL crystal oscillator, 4-pin 1/2 TTL crystal oscillator (also used
on TWGS) and 2-pin crystal (little metal canister about 1/4 the size of
1/2 TTL).  To be able to use a 2-pin crystal, your Zip must have a
resistor at R1 and capacitors at C13 and C14.  I've found these three
parts to be missing from current Zips. No big loss since 2-pin crystals
are less common and are only available up to a certain frequency.

     For experimenting with different frequencies it makes it easier if
you install a socket for the crystal oscillator.  It's also a good idea
to secure the module with one of those zip tie bands. Only 6 of the 14
pins are used (picture A). The ground (GND) pins 1, 4 and 7 are
connected together.  The power pins 11 and 14 are connected together. 
Full TTL crystal oscillators use pins 1, 7, 8 and 14 (refer to picture
B).  1/2 TTL crystal oscillators use the bottom four pins (4, 7, 8 and
14; picture C).  Make sure it's oriented correctly with the corner
(usually with a dot printed next to it) at about 11 o'clock.
 *WARNING*  The crystal oscillator will be damaged if installed
   GND  1 o     o 14  POWER     1 |o      \  14
   NC     x     x     NC          |        |
   NC     x     x     NC          |  FULL  |           ______
   GND  4 o     o 11  POWER       |  TTL   |        4 |o     \  14
   NC     x     x     NC          |        |          |  1/2  |
   NC     x     x     NC          |        |          |  TTL  |
   GND  7 o     o  8  CLOCK     7  \______/   8     7  \_____/   8
            (A)                      (B)                 (C)
   x - no connection (NC)


016- How do I modify my ZipGS to accept the new "skinny" RAM chips?

     With a little modification you can make a Zip with wide sockets
accept both the wide (600 mil) and the newer 300 mil skinny 32k x 8
Static RAMs (SRAMs). Ground yourself then carefully pry out the static
rams.  Look at the socket and you will notice two or three horizontal
bars holding both sides of the socket together (Picture D).  Carefully
snip those out (wire cutters work well for snipping plastic). This will
expose a column of holes. Now, solder in half of a socket.

     Refer to Picture E below. Plug your skinny SRAMs into the left and
center columns making sure the notch on the static ram is facing up--
i.e. toward top edge of board. (Applying power with a chip incorrectly
socketed could damage the chip.)
            ___           ___________ Skinny RAMs plug in here
           |   |         |   |          notched end facing up.
         ____ ____       _   _   _
        |o __V__ o|     |o| |o| |o|
        |o|  o  |o|     |o| |o| |o|
        |o|  o  |o|     |o| |o| |o|
        |o|  o  |o|     |o| |o| |o|
        |o|  o  |o|     |o| |o| |o|
        |o|  o  |o|     |o| |o| |o|
        |o|__o__|o|     |o| |o| |o|
        |o _____ o|     |o| |o| |o|
        |o|  o  |o|     |o| |o| |o|
        |o|  o  |o|     |o| |o| |o|
        |o|  o  |o|     |o| |o| |o|
        |o|  o  |o|     |o| |o| |o|
        |o|__o__|o|     |o| |o| |o|
        |o _____ o|     |o| |o| |o|

            (D)             (E)


017- Is it really necessary to increase board voltage
     to do a TWGS/ZipGS speedup?

     With the new 14 MHz parts, you should not need to mess with the
voltage at all. It _may_ be necessary to increase voltage at 15-16MHz
and will likely be necessary at higher frequencies (e.g. 20MHz).


018- If I do a TWGS/ZipGS speedup mod, what kind of performance
     increase can I expect?
This is just to give you a rough estimate of how much faster you might
be able to achieve...

     BenchMark v5.0 results:
 CPU        Stock    TWGS   TWGS   TWGS    ZipGS  ZipGS  ZipGS
 Version    ROM 01   1.8s   1.8s   1.8s    1.0.2  1.0.2  1.0.2
 Cache/Spd          32k/15 32k/15 32k/15   64k/?? 64k/?? 64k/??
 Clock Spd    2.8     15   13.75   12.5      16     15     14
           =======  ====== ====== ======   ====== ====== ======
 Sieve      410.00   99.00 108.00 117.00    98.00  99.00 110.00
 String    1151.20  270.00 292.00 303.67   259.00 262.00 282.00
 Float 1    472.00   92.33  87.00 111.33   123.00 128.00 135.00
 Float 2   1535.00  317.00 394.00 381.67   395.00 415.00 432.00
 Fibinacci 2006.00  605.00 634.00 645.33   507.00 523.00 548.00
 Integer   1553.40  307.00 330.00 346.67   420.00 431.00 443.00

 Dhrystone  236     1136   1063   1000       NA     NA     NA
     *              1351          1183     1282     NA     NA
* Dhrystone v1.1 re-compiled under ORCA/C v2.0.1

     System Software 5.0 QuickDraw II improvement test:

     Stock //gs:     5648 ticks
     TWGS 15 MHz:    1332 ticks (over 4x faster than stock)

If you look at the numbers, a 12 MHz or faster TWGS/Zip will make
everything just about 4x faster than a stock //gs.


From: Scott G.

019- How can I modify my ZipGS for more cache and more speed?

     The process described below is very simple. It aims for a speed of
12.5MHz (or better) with 64k cache. 

     First, you will need one of the new Western Design Center 14MHz
65C816's. Alltech Electronics stocks the WDC65C816-14MHz for $20.
Students, teachers, and professors can order the IC in single quantities
directly from WDC for around $7.

     Adaptors: Nearly all of the newer, faster 32k x 8 SRAMs are in
skinny 300-mil packages. If you would rather not modify your ZipGS for
the skinny SRAMs, Digi-Key stocks 300-mil to 600-mil adapter sockets for
about $7 each. The ones you want are part number A502-ND.  You can plug
a 28 pin SRAM into the 300-mil adapter socket and the adapter in turn
plugs into the 600-mil socket on the Zip. (If you have some spare
sockets lying around, you can build your own cheap, but that's another

     2-4 32k x 8 SRAM chips: There are many sources for 32k x 8 SRAMs
and several types that will work. I got mine (HM62832-15, $5 each) from
JDR Microdevices. You'll want 15ns in the Tag RAM sockets. Up to around
12.5MHz, you want 70ns or faster Data RAM. If current cache size is 64k,
your old TAG RAM chips will, usually, work as Data RAM and can be
transferred to the Data sockets. Otherwise, go ahead and get two
25ns-35ns 32k x 8 SRAM chips for the Data RAM.

     Data RAM should always be slower than Tag RAM. Barry Rees posted
his experiences on this matter (that Data should be significantly slower
than Tag) and I found that the original Tag chips were fast enough.

     A "full size" oscillator module: Digi-Key, JDR, Mouser, ... have
these.  Divide oscillator speed by four to get Zip speed. JDR has the
OSC50.0 (50MHz oscillator), which will make a 12.5MHz Zip. The
oscillators are cheap enough to get two or three for experimenting with
higher speeds.
     So, you just plug your Tag and Data RAM chips into the Digi-Key
adapters and plug the adapters into the Tag and Data sockets of the Zip.
Then, you install the new 65C816 and oscillator and make sure DIP switch
1-7 and 1-8 are both set OFF (for 64k cache). That's it, done completely
without soldering.

     ZipGS boards vary. On some you may be able to go above 12.5MHz by
just plugging in a faster oscillator. On others, you may have to choose
between getting faster Data RAM or settling for a lower speed. The new
65C816 is rated for 16MHz and many users have gone to 14MHz and above.
For speeds above 12.5MHz, the usual recommendation is to get Data RAM
rated at 35ns or better.

     For a step-by-step guide, download my ZipUpgrade.SHK HyperCard
stack at ... . 


020- Do I need new GALs to speed up my TransWarpGS?
     Not any more. The new 14MHz 65C816's available from WDC make it
unnecessary to swap in new GAL chips to go to higher speeds. 


From: Rubywand

021- I have an 8kB TransWarpGS. How does a cache upgrade compare
     with a speed upgrade?

     John Link charted some comparisons in 1991 involving nine setups:
no-TWGS, and 7, 8, 9, 10mHz boards before and after the 8kB-to-32kB
cache upgrade. He used three benchmarks:

1. time to calculate page breaks in a 218-page Appleworks document
2. time to scroll through a 39-page Awks-GS document
3. time to compile 4800 lines of MD-BASIC source code

For a 7mHz 8kB TWGS, the speed gain for the 32kB cache upgrade is
roughly 33% to nearly x2.5 plain GS speed.

For a 10mHz 8kB TWGS, the speed gain for the 32kB cache upgrade is
roughly 33% to about x3.25 plain GS speed. 

     His charts shows that a 7mHz TWGS with the 32kB cache performs
slightly better than a 10mHz TWGS with 8kB cache on tests 1 and 3; it is
a bit slower on test 2.


022- How can I upgrade my TWGS to 32k cache?

     SHH Systeme ( ), a German
company, sells the cache upgrade piggyback board in various states of
'do-it-yourself' readiness. The ready-to-go version is $69 (+ $14 S&H).
It includes three 32K cache RAMs (62256-15 or equivalent) and can
support speed upgrades to 14MHz or better.

     SHH does not automatically include the firmware ROM. If your
firmware version is not v1.7 or v1.8, you will also need to order the
v1.8 EPROM which SHH sells for $12. 


023- How can I upgrade TWGS speed?

     The process is very similar to that described earlier for the
ZipGS. That is, you swap in a new 14MHz 65C816, a higher speed
oscillator module, and, possibly, faster 32k x 8 SRAM chips.

     As with ZipGS, TransWarpGS speed = Osc Speed divided by 4. One
difference is that the TransWarpGS oscillator module is of the
"half-size" kind. Another is that, if RAM is upgraded, the usual
practice is for all three to have the same speed rating. If you do the
SHH cache upgrade, there should be no need to worry about replacing

     According to a 1992 Appleworks Forum article by John Link, you can
get to 12.5MHz with the new 65C816, a 50MHz oscillator, and 35ns SRAM.
Higher speeds would require faster SRAM. (The article mentions that
increasing power supply voltage to 5.5V allowed operation at 13.75MHz
with a 55MHz oscillator and 35ns SRAM; but, that malfunctions began to
occur after 2 hours.)

     TransWarpGS boards vary just as do ZipGS boards. Some can be pushed
to higher speeds than others. If you decide to do a speed upgrade, get
two or three oscillators to allow for some experimentation.

     For a step-by-step guide, download Scott G's TWGSupgrade.SHK.
HyperCard stack at ... . 


024- What kind of RAMs do I need for a TWGS or ZipGS speedup?
     You need fast 32k x 8 Static RAM in a 28-pin Dip package. If your
RAM sockets are "skinny" (about as fat as a typical 74xx TTL IC), you
want a 300-mil wide package. Otherwise, you will need a 600-mil wide IC
or a socket adaptor for 300-mil (or do the socket mods described earlier
in this FAQ).

     Fast 600-mil package 32k x 8 SRAMs are fairly rare. However, the
IDT71256 is supposed to be available at good speeds (25ns-40ns) in a
600-mil version from Integrated Device Technology.

     The selection of 300-mil 32k x 8 SRAMs is much larger: Cypress's
CY7C199, Hitachi's HM62256, ... .


From: Sandy

025- How can I tell the firmware version of my TWGS?

     With the IIGS turned on, press CONTROL-Apple-ESCAPE And go to the
Transwarp CDA  The ROM version will be displayed on the screen.


From: Mitchell Spector

026- Do I need I need the 2B GAL for my Transwarp-GS to use a
     SCSI interface? If I do, where can I get one? 

     The TWGS-2B GAL was a DMA fix Applied Engineering issued for the
board. It is an absolute requirement for Transwarp to work at all with
at least some RamFAST SCSI boards (e.g. the revision C boards).

     With Applied Engineering long since out of business and the GAL
virtually impossible to duplicate by convential means, that leaves no
good source for replacement GALs. I found it much more affordable (and
less hassle) to just purchase a used TransWarp GS board with the 2B GAL
to replace your old one.


From: Supertimer

     RamFAST revision D does not require the 2B GAL. The Apple High
Speed SCSI card works with all TransWarps GS units.


From: Rubywand

027- When I change my ZipGS's Speed, Misc, and Slot settings via
     the Zip CDA, they are always lost after turning OFF the GS.
     What's wrong? Do I need a new BatRAM battery?

     No. The reason the settings are forgotten is that they are not
saved in BatRAM or on-disk. ZipGS settings made via the Zip CDA or via
the Zip Control Panel are only in effect for the current session of


028- What do the check-marks mean next to settings in the ZipGS
     CDA? Are they original factory settings or what?

     More like "or what". The check-marks indicate the settings of the
DIP switches on your ZipGS board.


029- After installing my ZipGS along with the ZipGS CDA and other
     software I've noticed that my ZipGS settings never seem to
     match the ones I originally set via the on-board DIP

     There are two likely explanations. One is that your interpretation
of the settings is confused due to the rather poor explanations provided
in the Zip on-disk HyperStudio 'manual'. It does not help that
names/descriptions of the settings are not quite the same in the
'manual' and in the CDA or NDA.

     For info on setting your on-board DIP switches, see question 001.

     Another possibility is that when you installed the ZipGS software,
you installed ZipInit in your SYSTEM/SYSTEM.SETUP folder. If you did,
then whatever settings ZipInit is set up for will be the settings for
your ZipGS after booting. That is, ZipInit will over-ride your DIP
switch settings.

     ZipInit is intended for use on diskettes which, when booted, will
set up the ZipGS in some special way to match the software on the
diskette. For example, you might want to turn OFF the ZipGS or reduce
its speed when booting an arcade games diskette.

     The cure for unwanted influence from ZipInit is to delete it from


030- I have a ZipGS. Usually, it runs like a champ; but, sometimes
     when I power-ON my GS, I get an all-white screen and the computer
     just 'hangs'. What's going on?

     It may be that your ZipGS card is not making good contact in its
Slot socket. This is a fairly nasty problem which has led users to
pursue a number of false cures.

     With power OFF, pull your ZipGS board and inspect the
bottom-of-card connectors. What you will, most likely, notice is that
the connector traces end approximately 1/8 inch or so from the bottom of
the card.

     Unfortunately, the GS Slot sockets make contact rather near the
bottom of cards plugged into them-- roughly 1/8 inch or so from the
bottom. The reason your GS sometimes hangs is that, sometimes, the ZipGS
card is not making good contact with all Slot connectors.

     One 'cure' is to make sure the ZipGS card's contacts are clean and
that the card is thoroughly plugged in-- i.e. well lined-up with Slot
contacts and inserted as far as it will go into the Slot socket.

     A mildly tricky additional step is to use a small jeweller's
screwdriver to reach into the Slot socket and _carefully_
twist/pull/bend-out each contact very slightly (naturally, with power
OFF). You do not want any contact to normally touch a contact across
from it.

     Whatever, if your GS starts okay and does not exhibit the same kind
of hanging in the future, you know that the ZipGS card is well socketed.

     A more permanent, reliable cure is one _not_ recommended for
someone without experience working on circuit boards: You find a better
Slot connector socket-- one with gold contacts which touch plugged-in
cards higher up and with circuit board connections which will fit into
the original holes-- and replace the connector. This is a _very_ tricky
replacement which requires careful de-soldering of the original Slot
socket, cleaning of contact holes, and soldering-on the new socket-- all
without burning the circuit board or slicing traces on either side.
Actually, slicing traces is okay, IF you are prepared to repair the
damage. (Yes; I did this replacement on our GS. It works; but, If I had
known what a hassle it would be, I probably would never have done it!)


031- Ever since my accelerator speed upgrade it seems like my GS is
     always experiencing random system crashes. What's the problem
     and how can I fix it?
     When a GS equipped with an accelerator experiences frequent crashes
into the monitor after a speed upgrade, the usual explanations are ...  

  1. the accelerator is over-clocked for the microprocessor or RAM;

  2. there are serious noise spikes on the Slot power lines.

     If you are 'pushing' your current RAM or using an old 65C816, you
can upgrade to faster chips or swap in a slower oscillator.

     Often, the problem will be noise spikes related to increased
current load and/or increased sensitivity to noise related to faster
clocking. See the POWER FAQs (CSA2POWER.TXT) for Power Supply and
motherboard mods which should help.


032- I added a new accelerator board to my Apple and now my
     system is constantly bombing. What's the problem and how
     can I fix it?

     Most likely, the accelerator board's current load has led to
increased noise on the +5V bus. See the POWER FAQs (CSA2POWER.TXT) for
Power Supply and motherboard mods which should help.