Apple IIc acting STRANGE!
Bob Kupiec
while now. Here are the symptoms: Sometimes the character generator in
the machine will go nuts distorting characters, or "snow" will appear on
the screen. Other times the screen will totally flip out like someone has
messed with the monitor's horizontal hold. A "hiss" can be heard when this
happens.
I know that the problem *IS* with the COMPUTER! The monitor is FINE
and the video co-ax is FINE. The problem is WITHIN the computer. I
removed all the socketed chips (they seemed to have some kind of corrosion
on the pins which I partly removed) and re-seated them. It seemed to help
for a while but the symptoms still show up.
The motherboard is a Unidisk 3.5" model and not a "old" type. Is there
anything I should be looking at in particular? Do IIc's have this problem
or am I an isolated case? Any hints on where to start looking would be
helpful. I'm running out of ideas.
Please followup to the address below because I don't follow this newsgroup.
Thanks for your help!
--
\/\ Bob Kupiec - Amateur Radio: N3MML UUCP: (Machine is down, please) /\/\/
/\/\ Internet: kup...@hp800.lasalle.edu (use INTERNET address.) /\/\/\
\/\/\ LaSalle University, 20th St. & Olney Ave., Philadelphia, PA /\/\/\/
/\/\/\ Self-Quote: "I'm MS-DOS free: never had it, never will." /\/\/\/\
David D Kilzer
>There is a strange problem that has been occuring on my IIc for a
>while now. Here are the symptoms: Sometimes the character generator in
>the machine will go nuts distorting characters, or "snow" will appear on
>the screen. Other times the screen will totally flip out like someone has
>messed with the monitor's horizontal hold. A "hiss" can be heard when this
>happens.
>
>I know that the problem *IS* with the COMPUTER! The monitor is FINE
>and the video co-ax is FINE. The problem is WITHIN the computer. I
>removed all the socketed chips (they seemed to have some kind of corrosion
>on the pins which I partly removed) and re-seated them. It seemed to help
>for a while but the symptoms still show up.
>
>The motherboard is a Unidisk 3.5" model and not a "old" type. Is there
>anything I should be looking at in particular? Do IIc's have this problem
>or am I an isolated case? Any hints on where to start looking would be
>helpful. I'm running out of ideas.
>
>Please followup to the address below because I don't follow this newsgroup.
>Thanks for your help!
Have you tried a self-test? The older-ROM //c's didn't have the routine
built-in, but in the newer ones (including your's) have it. Try
pressing control--open-apple--closed-apple--reset. The computer should
go through a series of graphic "kaliescope" screens, then give you a
message about the system. If "System ok" appears, every thing "should"
be okay, but still may not be. If another message appears, I'd suggest
posting it to this newsgroup and asking what it means.
I had a similar problem recently. Whenever I turned on my //c, grave
accents would appear in strange places on the screen and flicker. The
computer would boot up, but any programs that required more than 64K
would crash (the 40-column screen looked fine, but the 80 column screen
had these grave accents on it). I came to find the problem was that one
of the RAM chips in the AUX bank (the extra 64K that makes the base //c
have 128K) went bad. Once I replaced it, everything works fine now.
One important note: If you have a Zip chip (or RocketChip) installed
or a memory expansion board, you might want to remove them before doing
the self-test. When I first did a self test with my 1 Meg. Z-RAM Ultra
II and 8 MHz Zip Chip installed, a "System ok" was returned. However,
once I removed both the Zip Chip and the memory expansion board and did
another self-test, I got the following message: "RAM* 0 1 0 0 0 0 0 0".
This told me that the second RAM chip from the top of the logic board
(top being the side with all the ports) in the AUX bank (indicated by
the asterisk) was bad. I ordered a replacement chip and new socket
(actually, two of each) from Alltech Electronics (see their ad in
inCider/A+; or write me for address & phone number).
If you get this error message, I can put you in contact with the guy who
helped me thru fixing my //c. He wrote me a ten or so mail messages
before I attempted to repair my computer. If you don't get this error
message (but I suspect you will :), you can still post to the newsgroup
and ask what it means. You may also be able to buy a replacement chip
from Alltech if it's another type of chip that went bad.
Good luck! *crossing fingers*
Dave
[P.S.--Yes, I sent the same message to the original poster.]
Andrew Guillaume
G'day !
David D Kilzer writes:
|Have you tried a self-test? The older-ROM //c's didn't have the routine
|built-in, but in the newer ones (including your's) have it. Try
|pressing control--open-apple--closed-apple--reset. The computer should
|go through a series of graphic "kaliescope" screens, then give you a
|message about the system. If "System ok" appears, every thing "should"
|be okay, but still may not be. If another message appears, I'd suggest
|posting it to this newsgroup and asking what it means.
My understanding is that there are at least three versions:
- the original //c
- the UniDisk 3.5 //c
- the memory expansion //c
Which of the "newer ones" has the built-in self test ? My //c was upgraded
from the first to the second version, but ctrl-oa-ca-reset doesn't seem to
do anything. Is there any way of calling the self test (via the monitor?)
Andrew Guillaume
a.gui...@trl.oz.au
David D Kilzer
I have the UniDisk 3.5 ROM board in my computer, and the self-test works
for me. You're sure you're holding down open-apple, close-apple, and
control at the same time, then pressing & releasing reset? Sometimes,
if you do it too fast, the self-test won't initiate. [I'm sure you did,
for the initiated, the apple keys can be sensitive (they work like and
ARE the joystick buttons) and you must have them held DOWN when
rebooting or doing the self-test.]
Also wait 5 minutes before deciding that you don't have the
self-test...it should complete itself in that time (actually less, but
wait 5 minutes to be sure). Additionally, the self-test graphics are
all in lo-res, while the ROM without the self-test has hi-res graphics
patterns displayed on the screen.
Finally, the "fourth" version of the //c logic board is the //c+, but
that really doesn't count. :)
Dave
[This information is taken from memory, which has not been proved to be
100% consistent. If I stated something incorrectly, by all means
correct me!!]
--
[ >The Davemeister< ][ __IMZADI__ ST:TNG Novel by Peter David ]
[ ddki...@iastate.edu ][ Riker (about Counsellor Troi): "She looked good ]
[ David D. Kilzer ][ naked. Okay, great naked. Okay, spectacular ]
[ ~~~~~~~~~~~~~~~ ][ beyond belief naked." ]
Jonathan N. Deitch
>G'day !
>My understanding is that there are at least three versions:
>- the original //c
>- the UniDisk 3.5 //c
>- the memory expansion //c
>Which of the "newer ones" has the built-in self test ? My //c was upgraded
>from the first to the second version, but ctrl-oa-ca-reset doesn't seem to
>do anything. Is there any way of calling the self test (via the monitor?)
Well ... the actual key command is supposed to be ctrl-closed apple-reset.
This will activate the self test on any //c. It might have been both apples
for the first one, but it's definately closed apple on the Unidisk version.
'til later ...
- Jonathan Deitch
Tony Hamaoui
That is really cool that the //c can diagnose itself. I have a
question how many colors can the //c display.
Andrew Guillaume
clarification:
|I have the UniDisk 3.5 ROM board in my computer, and the self-test works
|for me. You're sure you're holding down open-apple, close-apple, and
|control at the same time, then pressing & releasing reset? Sometimes,
|if you do it too fast, the self-test won't initiate. [I'm sure you did,
|for the initiated, the apple keys can be sensitive (they work like and
|ARE the joystick buttons) and you must have them held DOWN when
|rebooting or doing the self-test.]
So my first error was releasing all keys together.
|Also wait 5 minutes before deciding that you don't have the
|self-test...it should complete itself in that time (actually less, but
|wait 5 minutes to be sure). Additionally, the self-test graphics are
|all in lo-res, while the ROM without the self-test has hi-res graphics
|patterns displayed on the screen.
And my second error was not being patient :-)
Thanks to all who replied to my query. I'm reading this early at work, and
rang up my wife at home (who was getting breakfast ready for the kids), and
she tried it all out: it works indeed as David had mentioned.
Thanks again for your help.
Andrew Guillaume
a.gui...@trl.oz.au
Bob Kupiec
>There is a strange problem that has been occuring on my IIc for a
>while now. Here are the symptoms: Sometimes the character generator in
>the machine will go nuts distorting characters, or "snow" will appear on
>the screen. Other times the screen will totally flip out like someone has
>messed with the monitor's horizontal hold. A "hiss" can be heard when this
>happens.
>
>I know that the problem *IS* with the COMPUTER!
>The motherboard is a Unidisk 3.5" model and not a "old" type.
OK, here is a followup on some things I forgot to mention.
OA-CA-ctrl-reset says "System OK". What does this check anyway? RAM? ROM?
There is NO Zip or other speedup chip installed. However there is a
No-Slot clock installed. (sidenote: I've had the clock for 5 years now,
can I expect it to die soon? If so, can I replace the battery?)
Another person emailed and suggested the power supply as the problem.
(I forget your name/address at the moment, but thanks anyway.) This could
be a culprit, but I have not tested it yet. Anyone know the pinouts?
Which chip is responsible for character generation on the video monitor?
The IIc hasn't have the symptoms in a while now, but a cure when it would
go "nuts" was to lift the IIc about 2" and drop it. It cured the problem
90% of the time. The other 10% might have required multiple drops. This
leads me to believe a motherboard problem more than anything else. (I know,
not a smart idea to drop it, but it *DID* fix the problem!)
I ran a "IIc Dealer Diagnostic" disk on the IIc and all tests came up
clean. RAM, ROM, MMU, Char Gen, etc.
Thanks for your help so far. Maybe I will find the problem. Please
followup to the address below!
David D Kilzer
>In <91...@netnews.upenn.edu>, kup...@hp800.lasalle.edu writes:
>>There is a strange problem that has been occuring on my IIc for a
>>while now. Here are the symptoms: Sometimes the character generator in
>>the machine will go nuts distorting characters, or "snow" will appear on
>>the screen. Other times the screen will totally flip out like someone has
>>messed with the monitor's horizontal hold. A "hiss" can be heard when this
>>happens.
>>
>>I know that the problem *IS* with the COMPUTER!
>[...]
>>The motherboard is a Unidisk 3.5" model and not a "old" type.
>[...]
>
>OK, here is a followup on some things I forgot to mention.
>
>OA-CA-ctrl-reset says "System OK". What does this check anyway? RAM? ROM?
I'm not sure what all it checks, but it at least checks RAM. Anyone
know everything that is checked?
>There is NO Zip or other speedup chip installed. However there is a
>No-Slot clock installed. (sidenote: I've had the clock for 5 years now,
>can I expect it to die soon? If so, can I replace the battery?)
Yes, the lifetime of the battery is about 5 years (if I remember
correctly) and will probably die soon. You can't replace the battery in
the clock; you must buy a new one (I'm not sure if SMT takes back the
dead ones for a discount or not; you'd have to check).
>Another person emailed and suggested the power supply as the problem.
>(I forget your name/address at the moment, but thanks anyway.) This could
>be a culprit, but I have not tested it yet. Anyone know the pinouts?
Not I.
>Which chip is responsible for character generation on the video monitor?
I can't remember the location on the //c logic board, but I know it's a
socketed chip (the socket on my board has more places for pins than does
the chip that's in it). If you open up your //c, you should be able to
find it (although it may be hidden under the disk drive). Just read the
printing on the chip and/or the logic board.
You said later that you ran a diagnostic on it, so I'm assuming the
character generator is okay.
>The IIc hasn't have the symptoms in a while now, but a cure when it would
>go "nuts" was to lift the IIc about 2" and drop it. It cured the problem
>90% of the time. The other 10% might have required multiple drops. This
>leads me to believe a motherboard problem more than anything else. (I know,
>not a smart idea to drop it, but it *DID* fix the problem!)
Sounds like a loose connection somewhere...maybe in the video-out of the
//c or the video-in of the monitor. What I would suggest doing is to
take a pair of plyers and bend the leaves of the RCA plugs on both ends
of the cord so that a tighter connection is made between the computer
and the monitor.
So if the end of your RCA plug looks like this, bend the "leaves" in a
little to make the connection tighter (please forgive the ascii
picture--it's the best I could do in 5 minutes :)
bend in
\/
_______
/ \
/ _ \
bend in -> | <_> | <- bend in
\ /
\_______/
/\
bend in
Of course, don't bend them in TOO much...then you won't be able to get
the plugs in. :) This should prevent any loose connections in the
monitor cord. If this doesn't help, then it's probably a bad connection
on the logic board of the //c or inside the monitor.
BTW, does anything happen when you wiggle the cord (at either end) when
it's plugged in and the //c is on?
>I ran a "IIc Dealer Diagnostic" disk on the IIc and all tests came up
>clean. RAM, ROM, MMU, Char Gen, etc.
>
>Thanks for your help so far. Maybe I will find the problem. Please
>followup to the address below!
Dave
Jason Haskins
The //c, I believe, has four ROM versions. Version 255 is the oldest,
followed by 01, 03, and 04, I think it is. I think it's 03 and 04 that
are Unidisk compatible.
Kees Hendrikse
jas...@eskimo.celestial.com (Jason Haskins) writes:
> The //c, I believe, has four ROM versions. Version 255 is the oldest,
> followed by 01, 03, and 04, I think it is. I think it's 03 and 04 that
> are Unidisk compatible.
According to Apple's technote/IIc/#7 (Existing versions), there are 4 ROM
versions:
: 1) Original IIc ( $FBBF = $FF )
: 2) 3.5 ROM IIc ( $FBBF = $00 )
: 3) Original "Memory-Expandable" IIc ( $FBBF = $03 )
: 4) Revised "Memory-Expandable" IIc ( $FBBF = $04 )
From 2 on they're Unidisk compatible but they all support OA/CA 'exerciser
code' in some form.
This information seems to be uncomplete, because there is another version with
$FBBF = $00 which is not Unidisk compatible. This version has the exercise
routine (called 'banger') located at $C740-$C780 (like the original $FF-ROM)
with entry-point $C77C. If you enter this routine, you stay there forever.
There will *not* be any 'System OK' message. The listing has comments that
say:
: The following code is Teri's memory and soft switch exercise program. The
: only purpose is exercise, not diagnostic functions. This code is activated
: on a system without a keyboard, or when both open and closed apple keys are
: pressed during the reset sequence.
The Unidisk compatible '$00' version doesn't have a real 'banger' routine,
but falls through to the 'diagnostic' routine. Listing comments say:
: These routines test all 128K ram. All combinations of soft switches
: applicable to the //c are tested and verified. (...)
: The test will run continuously for as long as the open and closed Apple
: keys remain depressed (or no keyboard is connected) and no failures
: are encountered. The message 'System OK' will appear in the middle of
: the screen when an successful cycle has been run and either of the
: Apple keys are no longer depressed. Another cycle may be initiated by
: pressing both Apple keys again while this message is on the screen.
The Unidisk-compatible $00 ROM has this diagnostic code located $D4A9
--
Kees Hendrikse | email: ke...@echelon.uucp
|
ECHELON consultancy and software development | phone: +31 (0)53 836 585
PO Box 545, 7500AM Enschede, The Netherlands | fax: +31 (0)53 337 415
Dan Brown
which) in HiRes mode, and 16 in Double Hi Res mode. Hi Res is 280 x 192;
Double Hi Res is 560 x 192.
--> Dan
* Origin: L&L Support - Home of GBBS Pro (702) 322-5551 (1:213/312)
Tony Hamaoui
David....@bbs.actrix.gen.nz
> whats the difference between the undisk //c and memeory expansion //c.
The "memory expansion" IIc has an internal connector for a memory
expansion card. The "unidisk" IIc doesn't.
I believe the Applied Engineering Z-RAM works in earlier IIcs, by
plugging into the MMU and CPU sockets (or something like that).
A card plugged into the "memory expansion" IIc's memory expansion
socket is software compatible with the slot-based Apple IIe memory
expansion cards (such as the Apple II Memory Expansion Card and the
RAMFactor).
--
David Empson
Internet: David....@bbs.actrix.gen.nz EMPS...@kosmos.wcc.govt.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand