NJRoadfan said:
According to the Apple IIgs Technical Reference, the character ROM is stored in the Mega II chip, not the main ROM. The Mega II is also responsible for genera…
68kMLATroubleshootingby ElfenWed, 27 May 2015 - 04:11
Pitou said:
@Gorgonops, ok thanks, will try that.
I have another question about the ROM chip. it's a 128kx8, so it needs 17 lines of addresses in order to access the entire …
68kMLATroubleshootingby ElfenWed, 27 May 2015 - 04:09
According to the Apple IIgs Technical Reference, the character ROM is stored in the Mega II chip, not the main ROM. The Mega II is also responsible for generating text screens on t…
68kMLATroubleshootingby NJRoadfanWed, 27 May 2015 - 01:51
@Gorgonops, ok thanks, will try that.
I have another question about the ROM chip. it's a 128kx8, so it needs 17 lines of addresses in order to access the entire memory of the rom.…
68kMLATroubleshootingby PitouTue, 26 May 2015 - 21:30
@Elfen, very good suggestion, I would try that for sure.
However, with no drive connected , it stays on "Check status device" and a kind of bar run from left to right and right to…
68kMLATroubleshootingby PitouTue, 26 May 2015 - 20:46
I wonder if this is for all the characters in the ROM or just a segment of them?
Boot it up without the disk drives attached so it goes into AppleSoft Basic.
Then type the follow…
68kMLATroubleshootingby ElfenTue, 26 May 2015 - 18:04
techknight said:
Your not gonna see via corrosion AFTER you already washed it. You needed to take note of those beforehand.
Click to expand...
That's why I'm having troub…
68kMLATroubleshootingby ElfenTue, 26 May 2015 - 17:36
Well it's hard to tell if it's the ROM chip or the Mega II. I also played around with the scope and followed the schematics, but I'm not able to pinpoint the root cause.
Here they…
68kMLATroubleshootingby PitouTue, 26 May 2015 - 14:08
This happens if the ROM cant see the SWIM. grab the classic schematics and go throught it.
Your not gonna see via corrosion AFTER you already washed it. You needed to take note of…
68kMLATroubleshootingby techknightTue, 26 May 2015 - 12:36
Thanks for the suggestion, I don't get a flashing ?, yet. I removed the RAM card and it did not help, in a separate attempt, I removed the HD cable and the startup remains unchang…
68kMLATroubleshootingby Juror22Tue, 26 May 2015 - 06:08
As long as you got the flashing '?' inside a floppy disk icon, the Classic is or should be working. You got a Bong an you got video - that's 2 out of 3, which the third is booting.…
68kMLATroubleshootingby ElfenTue, 26 May 2015 - 05:56
Its weird that only text is having a problem. That and the ROM checksum is passing. The only other chip I can suspect having a problem is the MEGA II which contains the character g…
68kMLATroubleshootingby NJRoadfanTue, 26 May 2015 - 04:08
I picked up a Mac Classic (2MB, 40MB HD) and it was immediately subjected to a recap. As part of that process, I cleaned around the old cap areas with alcohol and re-tinnned the p…
68kMLATroubleshootingby Juror22Tue, 26 May 2015 - 03:52
It actually looks like what my vision does to me, from time to time. lol.
But I digress....
double data = missing upper address bit/select signal on character ROM.
68kMLATroubleshootingby techknightTue, 26 May 2015 - 03:26
Elfen said:
If it were a Mac SE/30, I'd say part of your video circuit has lost a couple traces.
Click to expand...
Something like this would be my guess as well. I don't…
68kMLATroubleshootingby commodorejohnMon, 25 May 2015 - 22:45
I can make out "System Good" on that image, but you say it freezes at that point? Interesting.
What cards are you running on the IIgs? Have you run it without cards?
If it were a…
68kMLATroubleshootingby ElfenMon, 25 May 2015 - 22:29
I have been unable to find out what the CFM and the dBA of the original Color Classic fan is. While I am doing an upgrade, I would like to move more air and perhaps use a fan that…
Yes, advantage of a TiBook! Also, 100GB is overkill for OS 9, but just enough for Leopard. *And* I can run my library of old Mac software (1983/4-1999 I think, maybe later than '99…
9.2.2 should fly along beautifully on the 1.0 Ti... not entirely sure about Leopard's performance however. I know as much as it will run, however it may be a little painful as I do…
68kMLASoftwareby SchmoburgerMon, 25 May 2015 - 21:01
For what it is worth you likely will not hate the experience as much as you might expect if you play your cards right with the initial setup... I actually go out of my way to use t…
68kMLASoftwareby SchmoburgerMon, 25 May 2015 - 20:37