Apple II FrequentlyAskedQuestions: Accelerators

Csa2 FAQs-on-Ground file: Csa2ACCEL.txt  rev013 3/28/1999

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The Csa2 (comp.sys.apple2) Usenet newsgroup Frequently Asked
 Questions files are compiled by the Ground Apple II site,
 1997 - 1999.



 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 fast.

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 what.

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 commands.


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 problem.


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

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 machine:

      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 above.

   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

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

     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 processor.

     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

     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 necessary.

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

 *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

     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 story.)

     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

     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 SRAM.

     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: Mitch 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 computing.


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 your


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 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 for Power Supply and
motherboard mods which should help.