ROM 3 Questions
william strutts
except for the actual ROM's. The First machine has two ROM's
marked 341-0748 and 341-0737. The Control Panel Screen
for this machine shows the options: Control Panel, Alternate
Screen Mode. The second machine has these ROM's marked
341-0728 and 341-0748 (this is a different size ROM than the
other machine, it is four pins shorter than the other Machine). The
Control Panel Screen shows Control Panel, Alternate Screen
Mode, Visit Monitor and Memory Peeker. Is there any difference
between the ROM routines? Why is there the obvious chip
size difference between the ROM's?
--
--
William R. Strutts - wrstr...@home.com - Whatever!
C'est moi! http://www.facelink.com/wrstrutts
Just hacking away...
Mark Cummings
mentioned. The ROMs are 28pin fitted to a 32pin socket. This also matches
the IIGS Hardware Reference Manual 2nd Edition. I noticed that the circuit
diagram shows only the 28 pin version, but pins are referenced to their
equivalent sockket position on a 32pin socket, rather than the chip pin
number. The screen printing on the ROM-3 motherboard also indicates it will
take a larger ROM as an alternate.
I'd say that second one you have is not normal, but a special, perhaps for
Apple technicians or programmers ? (just a wild guess). Maybe those ROMs are
only used to fault find the system, like checking for faulty DRAMs which
can't be found by running the System Self Test (speaking from a bad
experience).
Also, if you look at the KEGS emulator on the PC using ROM-3 code it also
doesn't have that Visit Monitor or Memory Peeker option.
I could probably guess, but tell us what they do ?
Mark
william strutts <wrstr...@home.com> wrote in message
news:yq407.154970$DG1.25...@news1.rdc1.mi.home.com...
David Empson
> I have two ROM 3 motherboards. They are basically identical
> except for the actual ROM's. The First machine has two ROM's
> marked 341-0748 and 341-0737. The Control Panel Screen
> for this machine shows the options: Control Panel, Alternate
> Screen Mode. The second machine has these ROM's marked
> 341-0728 and 341-0748 (this is a different size ROM than the
> other machine, it is four pins shorter than the other Machine).
Are you sure about the "341-0748" numbers being the same in both cases,
but in a different socket? That can't be right, unless someone has
mislabelled one of them. The same part number in a different socket
implies the ROM is in the wrong socket, but the machine wouldn't start
up in that case.
I assume you've just listed them in opposite orders, and the ROMs in
question are actually in the same socket.
One of the machines probably has a pre-release version of the firmware
(most likely to be the 341-0728 ROM). I don't have my ROM 3 handy, so I
can't check it against my own machine. I recall looking into this
several years ago.
I don't remember the details off the top of my head, but there was only
a very minor change between the beta and final version of the ROM 3
firmware, consisting of one initialization routine somewhere in the
memory manager, I think. My previous posting on the subject predates my
current News software, so I don't have a copy of my earlier posting on
hand.
> The Control Panel Screen shows Control Panel, Alternate Screen
> Mode, Visit Monitor and Memory Peeker.
The Visit Monitor and Memory Peeker CDAs are available on all ROM 1 and
ROM 3 machines, but they aren't supposed to be visible until you go into
the monitor and use the # command.
There is a minor bug in the ROM 3 firmware which means that it doesn't
initialize the memory location which determines whether or not these
CDAs are enabled. When you power on the computer, the vast majority of
machines happen to start up with this location set to zero, so these
CDAs do not appear until you use the # command.
For a very small number of ROM 3 machines, this location happens to
contain a different value when powered on (probably FF), so these CDAs
appear at startup.
This behaviour is an artifact of dynamic RAM - it tends to power up with
a particular pattern of values, and this will be reasonably consistent
for the same memory chip.
I know that Mitchell Spector's ROM 3 has this particular behavioural
glitch. I only recall ever hearing about one other machine which does
it.
(There is another possibility: the beta firmware version might
deliberately turn on these CDAs, but I don't recall noting that
behaviour when I examined the differences.)
> Why is there the obvious chip size difference between the ROM's?
The type of ROM chips normally used in the IIgs are a 28-pin 128Kx8 mask
programmed ROM. Mask programmed ROMs are the most reliable type, but
they are only cost effective if produced in large quantities (thousands
at a time).
For prototyping and development purposes, Apple would have used EPROM
chips (Erasable Programmable Read Only Memory).
An EPROM requires at least one and sometimes two pins which are not
required on a mask programmed ROM: programming voltage and program
enable. (Some also have an output enable pin, separate from the
required chip select pin.)
For a 128KBx8 EPROM, the minimum number of pins you need is 17 (address)
+ 8 (data) + 3 (power, ground, programming voltage) + 1 (chip select).
This gives a total of 29, so there is no way you can use a 28 pin
package for this capacity EPROM. The next largest standard package size
is 32 pins.
After the development phase, if Apple was producing a small number of
machines for an initial production run, they may have used PROMs instead
of masked ROMs (much cheaper for small quantities). The type of PROM
used would have been identical to an EPROM, except it comes in a plastic
case (EPROMs are ceramic) and would be missing the window for erasing.
Since it has the same signal requirements as the EPROM, it would also
need to be in a 32 pin package.
The ROM 3 motherboard (and possibly also the ROM 1 - I haven't looked
recently) has provision for using either a 32 pin EPROM/PROM or a 28 pin
masked ROM. A 28 pin chip goes in the bottom end of the socket, so
there would be four unused pins at the top.
David Williams
Just been sorting through my ROM 03 IIgs'
Out of 8 machines only one has these extra options in the menu. However,
looking at the motherboards & chips, all of them are 28pin ROM's fitted into
28pin sockets. They also all have the same part numbers (341-0748 & 341-0737)
This indicates that all ROM 03 machines should have these 'extras' but simply
do not display them for some reason
Cheers,
Dave
william strutts
"David Empson" <dem...@actrix.gen.nz> wrote in message
news:1evzxdp.nrjk3fwb8hxcN%dem...@actrix.gen.nz...
> william strutts <wrstr...@home.com> wrote:
>
> Are you sure about the "341-0748" numbers being the same in both cases,
> but in a different socket? That can't be right, unless someone has
> mislabelled one of them. The same part number in a different socket
> implies the ROM is in the wrong socket, but the machine wouldn't start
> up in that case.
Machine 1:
341-0748
341-0728
Machine 2:
341-0748
341-0737
You're right I listed them in opposite order according to my notes
I had written down.
> I assume you've just listed them in opposite orders, and the ROMs in
> question are actually in the same socket.
>
yes
<snip>
> The Visit Monitor and Memory Peeker CDAs are available on all ROM 1 and
> ROM 3 machines, but they aren't supposed to be visible until you go into
> the monitor and use the # command.
Would this happen if the PRAM battery was dead too? Or due to the
installation of a RamFAST card?
<snip>
> > Why is there the obvious chip size difference between the ROM's?
>
> The type of ROM chips normally used in the IIgs are a 28-pin 128Kx8 mask
> programmed ROM. Mask programmed ROMs are the most reliable type, but
> they are only cost effective if produced in large quantities (thousands
> at a time).
The 28 pin ROM has these numbers on them:
TC531000CP-F738
> For prototyping and development purposes, Apple would have used EPROM
> chips (Erasable Programmable Read Only Memory).
>
> An EPROM requires at least one and sometimes two pins which are not
> required on a mask programmed ROM: programming voltage and program
> enable. (Some also have an output enable pin, separate from the
> required chip select pin.)
>
> For a 128KBx8 EPROM, the minimum number of pins you need is 17 (address)
> + 8 (data) + 3 (power, ground, programming voltage) + 1 (chip select).
> This gives a total of 29, so there is no way you can use a 28 pin
> package for this capacity EPROM. The next largest standard package size
> is 32 pins.
>
> After the development phase, if Apple was producing a small number of
> machines for an initial production run, they may have used PROMs instead
> of masked ROMs (much cheaper for small quantities). The type of PROM
> used would have been identical to an EPROM, except it comes in a plastic
> case (EPROMs are ceramic) and would be missing the window for erasing.
> Since it has the same signal requirements as the EPROM, it would also
> need to be in a 32 pin package.
The longer ROM/PROM is marked Toshiba TC571001D-15 Japan
9015ECK.
> The ROM 3 motherboard (and possibly also the ROM 1 - I haven't looked
> recently) has provision for using either a 32 pin EPROM/PROM or a 28 pin
> masked ROM. A 28 pin chip goes in the bottom end of the socket, so
> there would be four unused pins at the top.
--
william strutts
the one with the 341-0737 chip.
--
--
William R. Strutts - wrstr...@home.com - Whatever!
C'est moi! http://www.facelink.com/wrstrutts
Just hacking away...
"David Williams" <Da...@darkstar64.freeserve.co.uk> wrote in message
news:3B41C956...@darkstar64.freeserve.co.uk...
Roger Johnstone
dem...@actrix.gen.nz (David Empson) wrote:
> The Visit Monitor and Memory Peeker CDAs are available on all ROM 1 and
> ROM 3 machines, but they aren't supposed to be visible until you go into
> the monitor and use the # command.
And of course you can also enable them using the SetStart control panel in
System 6.0.1, but they aren't available until after you boot the OS.
> There is a minor bug in the ROM 3 firmware which means that it doesn't
> initialize the memory location which determines whether or not these
> CDAs are enabled. When you power on the computer, the vast majority of
> machines happen to start up with this location set to zero, so these
> CDAs do not appear until you use the # command.
>
> For a very small number of ROM 3 machines, this location happens to
> contain a different value when powered on (probably FF), so these CDAs
> appear at startup.
>
> This behaviour is an artifact of dynamic RAM - it tends to power up with
> a particular pattern of values, and this will be reasonably consistent
> for the same memory chip.
>
> I know that Mitchell Spector's ROM 3 has this particular behavioural
> glitch. I only recall ever hearing about one other machine which does
> it.
Hmm, now that's something I had never heard of!
--
Roger Johnstone, Invercargill, New Zealand
Apple II - Future Cop:LAPD - Warcraft II
http://homepage.mac.com/rojaws
______________________________________________________________________
My software never has bugs. It just develops random features.
Mitchell Spector
>william strutts <wrstr...@home.com> wrote:
>
>> I have two ROM 3 motherboards. They are basically identical
>> except for the actual ROM's. The First machine has two ROM's
>> marked 341-0748 and 341-0737. The Control Panel Screen
>> for this machine shows the options: Control Panel, Alternate
>> Screen Mode. The second machine has these ROM's marked
>> 341-0728 and 341-0748 (this is a different size ROM than the
>> other machine, it is four pins shorter than the other Machine).
>
>One of the machines probably has a pre-release version of the firmware
>(most likely to be the 341-0728 ROM). I don't have my ROM 3 handy, so I
>can't check it against my own machine. I recall looking into this
>several years ago.
That was more than seven years ago, and you indeed did. I recall
your having done a complete disassembly and comparison between
the beta and standard (final; masked production) ROM 3 firmware in
great detail.
>I don't remember the details off the top of my head, but there was only
>a very minor change between the beta and final version of the ROM 3
>firmware, consisting of one initialization routine somewhere in the
>memory manager, I think. My previous posting on the subject predates my
>current News software, so I don't have a copy of my earlier posting on
>hand.
That's what Goggle/DejaNews is handy for. :) I just looked it up
and found it without too much difficulty. Actually it was a reposting
and near the start of when DejaNews began archiving messages.
Rather than post the link to that post (a URL which is over three
lines long!), here's a copy of that actual posting. My apologizes in
advance if the formatting isn't intact...
---------Begin post clipping------------------------------------------
Differences between the two versions of the ROMs in the ROM 3 IIgs
by David Empson (dem...@actrix.gen.nz)
Apple released two sets of ROMs for the "Apple IIgs with 1 megabyte of
memory", popularly known as the "ROM 3 IIgs".
The original set of ROMs has the serial numbers 341-0728 and 341-0729.
These are very rare: I only know of one IIgs that has been confirmed
to have these ROMs. [Make that two now]
The revised ROMs have the serial numbers 341-0748 and 341-0737.
These are by far the most common.
I have done a byte-for-byte comparison on the old and new ROMs, and
have identified the following differences:
Banks $FC and $FD are identical. [This means that ROM 341-0728 is
identical to ROM 341-0737.]
Bank $FE has changes in the following locations:
$FE345F (branch destination)
$FE3466 (branch destination)
$FE3475 to $FE349D (code changes)
Bank $FF has changes in the following locations:
$FF6232 (branch destination)
$FF623A (low byte of table address)
$FF623E (branch destination)
$FF6242 to $FF6260 (code and data moved due to an inserted
BRA instruction at $FF6242)
$FFFFF6 to $FFFFF7 (ROM checksum)
The Bank $FE Changes
====================
The changes in bank $FE are within an internal QuickDraw II routine
that calculates the memory address of a line, based on the current
LocInfo structure (i.e. pixel image base address, boundary rectangle
and row width in bytes).
The earlier version of the ROM 3 has a bug in this routine: if the row
width or line number is too large, the wrong address will be
calculated and QuickDraw will draw the object in the wrong place. With
the standard onscreen GrafPort (or an offscreen one of the same size),
this will not be a problem unless you try to draw past line 1023. With
a larger drawing area, as might be used by a high resolution printer
driver, for example, the line number limit is much lower.
For example, a driver printing at 300 dpi on paper 8 inches wide will
have 2400 pixels per line, requiring 600 bytes per line in 640 mode (2
bits per pixel). The bug in this routine will manifest itself if the
line number is 128 or higher (about a third of an inch down the page).
This routine is only used to calculate the start address of an object
-
subsequent lines will be drawn relative to the first address. This
means that a printer driver running at high resolution will not hit
this bug if the object starts at the top of the page (or very close to
it), until it tries to print the second band pass, which will start
further down the page.
This bug was noticed by Paul Bauer (pba...@mit.edu) when trying to
print a vertical line in the AppleWorks GS Page Layout module, using
the Harmonie Hewlett-Packard LaserJet II driver at 300 dpi. The first
part of the line was correct, but it had a break in it a certain
distance down the page and was drawn at the wrong horizontal position.
The problem was not evident on other ROM 3 machines, or if a lower
resolution was used. Paul had the older ROMs in his ROM 3.
The revised ROM 3 does not have this bug: it uses the Integer Math
toolset _Multiply routine, which can handle up to 65535 rows and 65535
bytes per row. The ROM 1 also uses _Multiply for this routine.
It looks like an attempt was made to do a much faster version of the
routine in the ROM 3 by doing the multiplication with a special case
routine, but it didn't allow for large enough images; Apple then went
back to the original code for the fixed version. There is also some
code in both ROM 3 versions to do a very quick calculation if the
pixel image width is 160 bytes and the line number is less than 400,
which will cover all onscreen drawing and a large proportion of
offscreen drawing as well.
The Bank $FF Changes
====================
The main group of changes appear to be part of the SmartPort code.
The routine that was modified is checking for a SmartPort INIT call,
and also checking for the presence of a ROMdisk. I haven't looked
into this one in detail, but I think the older version of the ROM 3
has a bug that prevents it from using a ROMdisk at all (or in certain
circumstances).
The other change is to the pair of bytes at $FFFFF6 and $FFFFF7.
These are in the middle of the interrupt vector table for the 65816,
and are defined as "reserved" in the 65816 data sheet (they would
be the emulation mode BRK vector, if it wasn't combined with IRQ at
$FFFFFE/F). The value in this location is meaningless and pretty
useless, so I suspect it contains a checksum of the ROM (or forces
the checksum of the ROM to add up to some magic number when
every byte or word is added, which is basically the same thing). The
value is $67E9 for a ROM 1, $A751 for an old ROM 3, and $6250
for a new ROM 3. Part of the patch to the QuickDraw routine involved
replacing several consecutive bytes with zeros, which may account
for the "lower" checksum in the new ROM.
What to do about it
===================
If you have been having strange problems on a ROM 3 IIgs with high
resolution printers not printing pictures correctly, or your ROMdisk
isn't working, then check the serial numbers printed on your ROMs. If
they say 341-0728 and 341-0729, you have probably hit one of these
bugs.
Alltech Electronics are able to supply replacement ROMs for the ROM 3
(the correct ROM numbers are 341-0748 and 341-0737). I believe they
charge US$29 for a replacement set of ROMs.
--------------end post clipping---------------------------------------
>> The Control Panel Screen shows Control Panel, Alternate Screen
>> Mode, Visit Monitor and Memory Peeker.
>
>For a very small number of ROM 3 machines, this location happens to
>contain a different value when powered on (probably FF), so these CDAs
>appear at startup.
>
>This behaviour is an artifact of dynamic RAM - it tends to power up with
>a particular pattern of values, and this will be reasonably consistent
>for the same memory chip.
>
>I know that Mitchell Spector's ROM 3 has this particular behavioural
>glitch. I only recall ever hearing about one other machine which does
>it.
I've since semi-retired the particular ROM 3 board and replaced it
with one where the bit location in the Slow RAM bank doesn't power
up in that unexpected state. So, I can now toggle the programmer
CDA's to 'off' and they remain off.
My board wasn't unique however. I did visit Apple Canada
in person to show them there was a defect with my board, when I
myself thought it was unique, but they convinced me otherwise
after showing me at least two or three other ROM 3's that exhibited
the same behavior. I vaguely remember discussing the problem
much later on with Apple and learning that a small number of these
boards were produced before the problem and caught and
corrected.
Another interesting thing about that board is it has gold colored
traces instead of dark green (my "fixed" ROM 3 board). It's worth
mentioning it would very often cold-boot in a dead state until I
firmly tapped the front tab on the case several times. After Tony
Diaz mentioned this was a particular trait of these gold trace
boards, I decided it swap it out. I've never seen the problem
since replacing the board.
>(There is another possibility: the beta firmware version might
>deliberately turn on these CDAs, but I don't recall noting that
>behaviour when I examined the differences.)
He may want to check if the option is for "Enable Programmer
CDAs" is checked off in the 'SetStart' Control Panel (NDA). That
changes the bit that's checked in bRAM so they'd normally always
show up even after powering down and back up again. Toggling
this option had no effect on my particular ROM 3 board.
Speaking of the ROM 3, I noticed my replacement board either
automatically activates hardware shadowing of text page 2 or it's
always flagged to 'on' via the Alternate Display Mode CDA. I had
a look an emulated IIgs in KEGS32 (both a ROM 01 and ROM 3)
and it acts identically. I can't seem to disable it with the CDA so
I'm not entirely clear on why the CDA is needed on the ROM 3.
Mitchell Spector
a_sp...@alcor.concordia.ca
David Empson
> "David Empson" <dem...@actrix.gen.nz> wrote in message
> > The Visit Monitor and Memory Peeker CDAs are available on all ROM 1 and
> > ROM 3 machines, but they aren't supposed to be visible until you go into
> > the monitor and use the # command.
>
> Would this happen if the PRAM battery was dead too? Or due to the
> installation of a RamFAST card?
It doesn't involve the PRAM, so the condition of the battery shouldn't
affect the appearance of these CDAs. The only factor is the contents of
a specific memory location in bank $E0 or $E1.
Power supply loading might have an effect on the dynamic RAM startup
state, so the installation or removal of a power hungry card like the
RamFast might influence this (but I doubt it).
> The 28 pin ROM has these numbers on them:
> TC531000CP-F738
>
> The longer ROM/PROM is marked Toshiba TC571001D-15 Japan
> 9015ECK.
The '531000' and '571001' parts strongly imply that the 28 pin chip is a
masked ROM while the 32 pin chip is a PROM.
The standard part numbers for an EPROM or PROM nearly always include a
'7' (e.g. 27C256, 27C010, 27C1001), with the distinction between an
EPROM and PROM being determined by suffixes or package types. The
corresponding masked ROM almost always has a similar part number with
'3' in place of the '7'.
There are two standard pinouts for a 128Kx8 EPROM/PROM. The most common
one is compatible with larger and smaller EPROMs/PROMs, allowing a
design to support mulitple capacities with room for firmware expansion.
The less common one (in my experience) has a slightly different
arrangement of pins which allows the EPROM/PROM to be replaced with a 28
pin masked ROM, as in the IIgs.
David Empson
Thanks for digging that up. I thought those archives had stopped
working, so I didn't even bother looking (besides, I was offline when I
wrote that article).
> Speaking of the ROM 3, I noticed my replacement board either
> automatically activates hardware shadowing of text page 2 or it's
> always flagged to 'on' via the Alternate Display Mode CDA. I had
> a look an emulated IIgs in KEGS32 (both a ROM 01 and ROM 3)
> and it acts identically. I can't seem to disable it with the CDA so
> I'm not entirely clear on why the CDA is needed on the ROM 3.
If you have alternate display mode enabled (i.e. text page 2 shadowing
is on) for a ROM 3, there will be a small performance hit for all memory
writes in locations in the range $0800 to $0BFF in bank 0, with the
write being forced to run at 1 MHz so that it can be mirrored into bank
$E0.
Under ProDOS-8, while running BASIC.SYSTEM, this is the code area for an
Applesoft BASIC program, which would only be written when loading a
program into memory, during editing, or variables being written for a
very small program.
For other ProDOS-8 applications, it would be necessary to determine how
this area is being used on a case-by-case basis.
Under GS/OS, this area is almost always stack or direct page space for
the current application, and may get accessed frequently.
You probably wouldn't be able to notice the performance hit unless the
program was using this area very often.
william strutts
"David Empson" <dem...@actrix.gen.nz> wrote in message
news:1evzxdp.nrjk3fwb8hxcN%dem...@actrix.gen.nz...
> william strutts <wrstr...@home.com> wrote:
> > The Control Panel Screen shows Control Panel, Alternate Screen
> > Mode, Visit Monitor and Memory Peeker.
>
> The Visit Monitor and Memory Peeker CDAs are available on all ROM 1 and
> ROM 3 machines, but they aren't supposed to be visible until you go into
> the monitor and use the # command.
>
> There is a minor bug in the ROM 3 firmware which means that it doesn't
> initialize the memory location which determines whether or not these
> CDAs are enabled. When you power on the computer, the vast majority of
> machines happen to start up with this location set to zero, so these
> CDAs do not appear until you use the # command.
>
> For a very small number of ROM 3 machines, this location happens to
> contain a different value when powered on (probably FF), so these CDAs
> appear at startup.
>
> This behaviour is an artifact of dynamic RAM - it tends to power up with
> a particular pattern of values, and this will be reasonably consistent
> for the same memory chip.
>
> I know that Mitchell Spector's ROM 3 has this particular behavioural
> glitch. I only recall ever hearing about one other machine which does
> it.
>
I located another ROM 3 yesterday which I bought for the cards
and it has the same menu items available.
william strutts
"Mitchell Spector" <a_sp...@alcor.concordia.ca> wrote in message
news:3b43e3fd...@newsflash.concordia.ca...
> dem...@actrix.gen.nz (David Empson) wrote:
>
> ---------Begin post clipping------------------------------------------
>
> Differences between the two versions of the ROMs in the ROM 3 IIgs
>
> by David Empson (dem...@actrix.gen.nz)
>
> Apple released two sets of ROMs for the "Apple IIgs with 1 megabyte of
> memory", popularly known as the "ROM 3 IIgs".
>
> The original set of ROMs has the serial numbers 341-0728 and 341-0729.
> These are very rare: I only know of one IIgs that has been confirmed
> to have these ROMs. [Make that two now]
>
> The revised ROMs have the serial numbers 341-0748 and 341-0737.
> These are by far the most common.
>
I now have three ROM 3 boards:
Machine 1:
341-0748 (28 pin plastic ROM chip)
341-0728
Machine 2:
341-0748 (32 pin PROM/EPROM plastic package)
341-0737
Machine 3:
341-0749 (32 pin EPROM ceramic package)
341-0728
Sorry if this mucks up the waters. Was there some kind of
field bug fix that might have happened on the machines since
they don't conform to the quoted statements above? The ones
with the 341-0728's should also have the 341-0729's as well
but the two that do have it have different ROM's.
Mark Cummings
> > > The Visit Monitor and Memory Peeker CDAs are available on all ROM 1
and
> > > ROM 3 machines, but they aren't supposed to be visible until you go
into
> > > the monitor and use the # command.
Maybe I have misread this, but I tried pressing # in about a hundred ways,
and still didn't get the extra options on eithre my ROM-1 or ROM-3.
Does this mean I don't have it in my ROMs, or that I'm not pressing the
right sequence of keys or at the right screen in the control panel ????
Mark
Mark Cummings
the control panel, not the monitor. Doh!
Mark
Mark Cummings <NOTfi...@primus.com.au> wrote in message
news:3b44411e$1...@news.iprimus.com.au...
David Empson
Talk about throwing a spanner in the works. I hadn't heard of a
341-0749 ROM before. The higher number implies it is newer than the
main ROM 3 release (341-0748 and 341-0737).
Perhaps this is the mythical ROM 4?
> Was there some kind of field bug fix that might have happened on the
> machines since they don't conform to the quoted statements above?
> The ones with the 341-0728's should also have the 341-0729's as well
> but the two that do have it have different ROM's.
As noted in my old post, 341-0728 is identical to 341-0737, so there is
only one ROM to investigate. The changes from 341-0729 to 341-0748 are
known. The only question is what changed between 341-0748 and 341-0749.
I can't say anything about what might be in this 341-0749 ROM unless I
can get hold of a copy of its contents and repeat my earlier
investigation, comparing it to the 341-0748 ROM.