Discuss Mac ROM problems.

52 responses total.

What sorts of problems do Mac ROMs tend to have?

Tonight my dusty but trusty Mac SE failed while on. I tried to use it
after it had been on but idle for a couple of hours, and found the desktop
frozen. I noticed that the window was incomplete - the window name bar
(including staff) was missing. It was unresponsive to all keys and mouse,
so I tried to reboot it with the reboot button. The screen went dark and
then the Sad Mac appeared. I then followed the Rule of Three. I turned it
off and on again - NG. I turned it off and on again with the shift key
depressed - NG. I unplugged its external SCSI HD, and attempted to turn it
on with a System Disk in the internal floppy drive - NG. The Sad Mac's
error codes were, line 1, 00000001 (meaning ROM problem), and line 2,
0000FFFF (I don't know that one). 

What alternative diagnoses are likely, and what would anyone recommend (to
fix it - I already thought of buying a new Mac)? 

#1 slipped in - boy, some people are fast on the draw!  ;->  But feel
free to discuss *any* Mac ROM problems - it may help me.

This seems unlikely, but I wonder if it could have to do with the
battery-backed parameter RAM.  Doesn't sound like it, but maybe 
it's worth checking the battery.  (I *think* SEs have regular
batteries.)

 I'm not much of a computer diagnostic person, but methinks thy Mac has given
up yon ghost. Time to getteth thee to PD. ;)

The system locked up while it was on but idle, so a battery failure could
not be the immediate cause. The SE has a lithium *clock* battery, but
I can't find any mention of a RAM backup battery - is there one? Also,
there are other Sad Mac error codes for SIMM problems. If it is a failure
in the ROM chip, can't this just be replaced (by me)? Of course, it could
be a loose wire associated with the ROM, or....

The thought has indeed crossed my mind that now may be the time to upgrade,
thought I would still seek to fix the SE, and find a home for it (maybe
our daughter would like it - she uses it quite a bit for games now and
maybe more soon). 

Humm.  Theses codes are not mentioned in the limited info I have.  My info
says to push the interrupt button while applying power to get it to display
error codes.  I'd try another set of RAMs or just re-seating the existing
ones.  (I got a Mac IIcx at PD for $40.  No memory, HD, keyboard or mouse
but it worked once I added all those things :-)

I think the "clock battery" keeps a little "parameter ram" refreshed, too.

Its not RAM - the error code is different. The interrupt button doesn't do
anything, as it has been stopped in its tracks at too early a stage. Does
a Mac have a replaceable ROM chip? (My source of error codes is MacWorld's
publication _Secrets_, but it does not get very technical.) I guess I better
check out PD, though, and get back up quickly. The SE is mostly my
wife's machine, and she first mentioned "color!", and then mentioned
that she really doesn't do anything on it much more recent than the 80's...
this may be a long decision process. 

Try putting it in the fridge for a few minutes, then see if there is any
different response.

There used to be a black market trade in Mac Plus ROM chips, so those are
swappable, and I imagine Mac SE's are the same.  People used to build Mac
clones with the black market chips...companies would upgrade the ROMs in
someone's Mac, then sell their old ROMs (they were supposed to return them
to Apple).

Get a couple of 27512 E-PROMs and I'll fire up the ole back box and make
ya a couple.  They'll have to be 120ns or faster.  You can also pick up a
Mac Plus form PD for $10 and nab the ROMs out of one of those.

Mac SE ROMS are not upgrades on Mac Plus ROMS? What about the slide show
of the SE development team in that ROM? Or is that the only change? Would
those EPROMS be like Mouser's 511-M27C512-10F CMOS 100ns? They're only $5
ea. That would be great, Klaus. Certainly worth a try. I'll have to order
the right EPROMS first. Even if the increasing family clamour for a
*color* computer succeeds....the SE would be handy for some jobs
(translate that as, I *really* have trouble throwing anything away....). 

The SE Roms support Color QD. They are way differen from those found on a
plus.

Gads, and I though SE and Plus ROMs were the same.  I have a a couple Plus
ROMS you can try before you purchase the EPROMS...  People use to tell me
that 9 bit SIMs wouldn't work in a Mac.  Ha!  Most of the SIMs in my Macs
*are* 9 bit and they all work just fine!  If you want to give it a go Rane,
bring your SE by, after giving me a call, some evening.

To the extent I understand this stuff...I'd prefer to try SE ROMS. Are
those what you are able to load to EPROMS, Klaus, or just Plus ROM? I
don't think I need Color QD (?) - the SE being B&W - but I probably have
other stuff that is now SE dependent. The SE introduced an expansion
slot, a SCSI port, and two floppy drives (which our's has). 

I don't have a SE.  Just a 512, Plus, PB-160 and a IIcx.  The ROMS I
was planning to copy are out of a Plus.  I figured the Plus ROMS are the
same as the SE ROMs.  A friend has Plus ROMs in his Outbound, a 20 MHz,
030 PB clone made a few years back.  I wouldn't be surprised if the ROMs
out of a Plus would work in your SE.  The Plus also has a SCSI port and
I run mine with 2 800K floppies, no problem.  Does yours have the 1.4 M
high density drives Rane?

No. 
We'll probably do something first about a new system (color!), and then
can fiddle around with the SE. It may not even be a ROM chip fault, though
that's what the error message says. I'll call to bring the SE over when
we get straightened out, and the Plus ROMs could be tried.

I went back and thought about this, and realize I must have become confused.
Sorry about that. The CQD support is in the SE030 ROMS, not the SE.
Color monitors can be attached to an SE030, but not an SE.
I don't know whether the Plus and SE Roms can be interchanged or not.
The SE is the first "open" Mac. I.e. it has a slot for a card.
The plus does not.  

Anyway - sorry I introduced errant info to this discussion.

The following is the question I asked a UM department computer guru, and
his response - how hard is it to desolder and replace a soldered-in chip?

>And, while I am asking about this... The SE died with a Sad Mac showing
>the error codes 00000001 (which means a ROM failure), and 0000FFFF (which
>I don't know what it means). Do you think just replacing the ROM chips
>would do any good? A friend is offering a couple of Mac *Plus* ROM chips,
>though I think that loses some functionality (does it?). Do *you* have
>access to SE ROM chips?

On the SE, Sad Mac error codes are usually of the following format:

        xxxxyyyy
        zzzzzzzz

In this case, yyyy=0001 which is indeed indicates the ROM checksum test
failed.  The zzzzzzzz code is usually used to give extra info (i.e. it can
tell you which bits failed when a RAM test fails.)  In the case of your
computer, it is meaningless.

Almost certainly, your computer can be fixed by replacing the SE's ROM
chip.  However, I don't have access to ROM chips.  You cannot use Mac Plus'
ROM chips because they do not contain code that allows for power testing
and 32-bit suppport.

My only recommendation would be to check out places that resell old macs
(particulary mail-order places) and see if they're willing to sell you an
old SE ROM.  It may cost almost as much as a used SE itself in which case
it may not be worth it.  Also, replacing the old ROM with the new ROM is
not trivial since the ROM chip is soldered onto the motherboard.

It may be worth it to see if you can get any money for the parts from a Mac
reseller and apply it towards the new computer you're getting.

[Any offers? --rcurl]

The difficulty of desoldering & resoldering a chip depends on the type of 
chip.  If it's got big, well-spaced pins (e.g. 1/10" apart) that stick
through a simple (i.e. non-layered) circuit board, it should be relatively
easy.  If it's a surface mount chip with pins you can barely fit a hair
between, then you've got a serious challenge on your hands.

Those mother boards are at least four layers so it acts like a great
heatsink and will make it difficult to heat those solder joints to the
point where the solder melts.  On boards like that I clip all the pins
at the IC, allowing the pinless IC to fall away, and then work on 
removing each of the pins one by one.
 
$100 or less will net you a used SE from PD.  Just take a system boot
disk with you to test them and a paper clip to extract your disk.  
You can bargin a better price if you find one the doesn't work, as
in no video, etc.  I've had very good luck getting working junk there.
 
(Or you can get a SE-030 for $250...)

I've found an outlet that sells Mac SE motherboards for $49 (plus s/h).  I
presume that would be without RAM, which I could transfer. How hard is it
to change a motherboard? [Since I've gotten a PowerMac to replace the SE,
you may well ask why I would want to do this - I ask this myself. The
answer is, I have great difficulty throwing anything away if I can fix it
relatively economically.  Why, I'd have an SE for use as a terminal, or a
X-10 control interface, or to use in the shop, or the bathroom.....) 

Well Rane, I have a hard time throwing things out too.  I fully understand!
Those early Macs were, and remain, very nice, friendly, computers.  I hsould
think that changing out the mother board would be a lot more trivial than 
replacing the soldered in ROM.  If you run into trouble let me know and you
can bring it over some evening.  I have all kinds of Mac compatable Torx 
drivers and the like..  (I was even contemplating offering to buy your old
SE from you ;)

Make an offer.... 8^}

Hummm.  Well, does it come with kbd & mouse?  How big is the HD?  Memory?

kbd & mse; 2 800K flps; no HD (ext 40MB Rodime was used); 4 MB RAM; lake view.

The same vendor that has an SE m-B for $50, offers an SE/30 M-B for $80. What
more would it take to upgrade the box to an SE/30?

I think there were some significant differences between the the innards of
a SE and a SE 030.  I've had 030's and SE's in pieces, but don't recall 
the diffefences.

I vaguely recall that one had to buy a new motherboard, but I don't know what
else. 

I've used an SE that had been upgraded to an SE/30 by switching the
motherboard.  I was under the impression that that was all that had had to
be done, but I didn't do the upgrade so I'm not entirely sure.

Well, that should be pretty easy than.  If I were doing it I would also
replace the floppy drive with a super drive for better PC compatability
and because a lot of software is distributed on 1.4M floppies.
 
I've decided against making you an off on your Mac Rane.  I simply have
too many other things to keep me busy for the foreseeable future.  I have
*plenty* of 68000 Macs too!

I thought you did, Klaus. 

My SE has 4 MB RAM, but the SE/30 can hold 256 MB, so a RAM upgrade is
possible. I don't know if the same SIMMs are used, though. The SE/30 also
supports 1.4M floppie, but I don't know if it supports two. Where could I dig
up SE upgrade instructions?

And what is an X.10?  <Chaz blushes with cluelessness>

A device for turning on and off AC throughout your house. The signal 
travels through the AC pwer from an X.10 controller to the modules. The 
controller has a serial interface, and can plug into any computer's 
serial port.

The controllers rarely have a serial interface.  Radio Shack sells this stuff
as "Plug'n'Power".  The modules can be installed like light switches, or else
they are little things like surge-suppressor wall warts you plug the whatever
into, then plug the whole thing into the wall.

I did?  What did I offer you, Rane?
 
You can also get X-10 controllers that interface to mac and PC serial ports.

Oh, I didn't know they existed, and suggested that they should once.  Sending
packets through the electical wires and all.  Oh, well.

I *thought* you did, Klaus ("have *plenty* of 68000 Macs"). The X-10
"controller" that interfaces to a computer is a stand-alone computer
itself (about the size of a paperback), which you just program by
downloading the schedule. It runs on house current, and has a backup
battery for power interruptions. I now have 21 circuits controlled (though
this is making much progress with my SE --> SE/30, or whatever). 

Do you experiance problems with the controller sometimes not turning 
something on when it's suppose to?  I found that I had to send two or
three sequential ON and OFF commands to be sure things actually were 
turned On and OFF.
 
So do you want to trade your SE for a working 512KE with 20M SCSI
HD and 4M of RAM?  How about a Triplite 200W inverter?

- Backtalk version 1.3.30 - Copyright 1996-2006, Jan Wolter and Steve Weiss