68kMLA Classic Interface

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My IIfx progress
Posted by: olePigeon on 2023-04-20 12:24:33
Unequivocally. This one actually got a US theatrical release. 🙂 It's just a lot of fun.
Posted by: pezter22 on 2023-04-20 18:07:25
Nice work. I have two Maxell battery bombed Mac IIfx boards. I've been able to repair the startup/shutdown circuit. I also repaired many of the broken traces, but weird thing is when BOTH are powered on, I instantly get the death chime and no video. It's been frustrating. I haven't looked at them in a few months, but reading your post has inspired me to jump back in. Keep it going.
Posted by: SophieRose on 2023-04-26 10:38:44
Recapped and powered up.. happy chime then stuck on a grey screen with square corners.. hmmminstasquare.photoeditor.effect.cutout_202342618369248.png
Posted by: LaPorta on 2023-04-26 10:42:23
You sure your graphics card is ok? Do you have a different one to test with?
Posted by: SophieRose on 2023-04-26 10:46:25
You sure your graphics card is ok? Do you have a different one to test with?
Yeah I tried a radius 24 and it hangs on the radius splash screen.
Posted by: LaPorta on 2023-04-26 10:52:44
What are you using to start it? A known-good HD or SCSI2SD sort of thing? What happens if you disconnect the SCSI drive? Do you get the blinking question mark or the same thing?
Posted by: SophieRose on 2023-04-26 10:55:49
It does the same thing with or without a hard disk or bluescsi connected to the internal bus. I dont have anything connected to the external scsi.. dont know how picky the iifx is regarding termination but its not even getting to the question mark or rounded corner screen.
Posted by: Phipli on 2023-04-26 11:05:20
Try the RAM in one bank at a time? Although I'd expect a sadmac... ROM is running, passing checksum...

How long have you left it, the ? Takes quite a while with no floppy drive connected, is there one?
Posted by: LaPorta on 2023-04-26 11:10:27
Try the RAM in one bank at a time? Although I'd expect a sadmac... ROM is running, passing checksum...

How long have you left it, the ? Takes quite a while with no floppy drive connected, is there one?
That's what I was thinking, it is passing RAM tests and chiming. How much RAM is installed?
Posted by: SophieRose on 2023-04-26 11:19:08
Tried both ram banks.. 4 of the 8 simms were giving death chime so swapped em all around to check all the slots worked with the good ram. I tried a bmow rom simm and same thing. I dont even get a mouse pointer or rounded screen edges.. i waited 10 minutes, none of the ics are getting too hot. instasquare.photoeditor.effect.cutout_2023426191658623.png
Posted by: LaPorta on 2023-04-26 11:25:53
would need to know just what in the startup sequence there is going on between those times...and I don't know that nearly intimately enough.
Posted by: Phipli on 2023-04-26 12:25:10
would need to know just what in the startup sequence there is going on between those times...and I don't know that nearly intimately enough.
Cough...

This might be too much detail and too old machine :

Mac GUI :: Macintosh Startup Revealed: From Boot Blocks to Finder

Apple news, photo galleries, downloads, and discussion forums.
macgui.com macgui.com

But it might help.
Posted by: Phipli on 2023-04-26 12:29:56
bmow rom simm
Understanding you've tried both, but just in case you or others don't realise, it's worth sticking with a stock ROM when troubleshooting because the BMOW ROM doesn't do the memory test.
Posted by: Phipli on 2023-04-26 12:37:07
This seems to be where you're getting to :

Boot Screen

The familiar gray boot screen, or "question-floppy screen" as I like to call it, is set up at $400464. QuickDraw is initialized, the screen is again cleared to black (this is probably redundant). The arrow cursor is setup, but not shown, at $40047C. A large, rounded rectangle is drawn in 50% gray.

Strage, in the 512k ROM it fills black, then draws a rounded Rect. If this is also the case on yours, perhaps it is failing while drawing the rounded rectangular? Or perhaps it is just a little different?

I can only see toolbox calls between the grey fill and drawing the mouse. It seems to be in these drawing routines. Given the drawing managed the first bit, shall we say... check your ADB circuit? And VIAs? Perhaps the mouse has an invalid behaviour when it starts trying to draw it???
Posted by: joshc on 2023-04-26 12:49:49
The 'Guide to the Macintosh family hardware' book by Apple may help here, as well as some information from Apple's "Inside Macintosh" books.

archive.org

Guide to the Macintosh family hardware : Apple Computer, Inc : Free Download, Borrow, and Streaming : Internet Archive

Macintosh: Guide_to_the_Macintosh_Family_Hardware (Second Edition)
archive.org

Page 244 explains what happens when an SE/30 or II-family Mac is powered on/starting up:

1682538072414.png

The rest of the process is described here


ADB, Sound and SCSI come after the grey boot screen appears - so I think @Phipli is right in suggesting looking at ADB and VIA circuits next.

Don't forget to refer to the Bomarc schematics - they are not completely correct but provide at least some pointers if you want to check over the ADB and VIA circuits.
Posted by: Phipli on 2023-04-26 12:56:15
ADB, Sound and SCSI come after the grey boot screen appears - so I think @Phipli is right in suggesting looking at ADB and VIA circuits next.
The VIAs have already been brought up and tested by the rom at that point, I was thinking regarding any interrupt triggers. I think I might be getting mixed up with the mouse on older macs when it was more involved with the VIA.

Probably OK to ignore the VIAs.
Posted by: joshc on 2023-04-26 13:08:00
Yes, that makes sense.

Step 2 of the system initialisation sequence is completing OK.

But I'm not sure that it's completing everything in step 3.

2. On machines with expansion slots, the initialization code initializes the Slot Manager.
The Slot Manager then initializes any installed cards by executing the primary
initialization code in each card’s declaration ROM. Video expansion cards, including
built-in video, initialize themselves by determining the type of connected monitor,
and then set the display to 1 bit per pixel, and display a gray screen (alternating black
and white dots).

3. The initialization code initializes the Vertical Retrace Manager and Gestalt Manager.
ROM drivers for all built-in functionality are installed in the unit table and initialized.
The initialization code initializes the Apple Desktop Bus (ADB) Manager that then
initializes each ADB device. The initialization code initializes the Sound Manager and
SCSI Manager.
Posted by: SophieRose on 2023-04-26 15:01:27
Thanks for all the advice, at least I've a starting point where to look. Cheers
Posted by: cheesestraws on 2023-04-26 15:06:19
Yes, this looks like it's crashing after primary init and probably before secondary init. Unfortunately that doesn't narrow it down much.
Posted by: SophieRose on 2023-04-27 13:05:32
I've found a transistor in the ADB circuit thats corroded away, schematics says it's a MMBT2904, I can't find any for sale.. Does anyone know what a suitable replacement would be?
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