Search results

Yes you can use them. I meant to say you can't trust them. Usually the current rating is a minimum that the adapter can supply without damage to the adapter. It does not mean the adapter can't supply more current - at least for a short time. If the Mac can force an amount of current from the...

You're saying that Apple put current limiting features in the power adapter instead of inside the Mac. You can't use third party power adapters if that's true. You would have to test the adapter to verify how much current you can draw from it. What happens to the adapter when that current limit...

What version of Open Firmware does your iMac have? Output from dump-device-tree might be useful. https://forums.macrumors.com/threads/question-how-powerful-of-a-graphics-card-will-work-in-a-beige-power-macintosh-g3.2303689/ Looking at Open Firmware 4.1.9f1 (for a slot loading iMac G3), it...

I don't think there's such a thing as a current rating that is too high? Voltage is controlled by the AC adapter. Current is controlled by the load (the Mac). The Mac is not going to use more than it normally uses. The power supply needs to have a current rating that matches or exceeds whatever...

Service Source for the 7300 says the DIMMs must be 5V and that fast paged DIMMs also work. http://www.applerepairmanuals.com/the_manuals_are_in_here/PM7300_7500_7600_WS7350.pdf It says you can increase the memory to 512 MB. That would require eight 64 MB DIMMs. I'm pretty sure 128 MB DIMMs...

They all have different version numbers and therefore different 3 MiB checksums and different 4 MiB checksums. They all have different Open Firmware code. Rev A and Rev B are both 2.0f1 but Rev B has some updates. Rev C and Rev D are both 2.4 but Rev D has a small change. 077d.40f2.1 "Boot...

I had some more Serial Test Manager notes at https://tinkerdifferent.com/threads/new-diagnostic-tool.4593/post-39652

Does that apply to all 4 revisions of the Beige G3 firmware? Does that apply to Mac OS 9 as well? I've seen Mac OS 9 is able to see partitions beyond 128 GiB. I know that early versions of Open Firmware (e.g OF 2.4) have bugs related to detecting LBA28 and don't have code for LBA48. I think...

Was this image 2352/2048 times bigger than the partition created from disk2s1? If so, then it does contain all of the partitions. It's just in a different format than expected. Examine your disk images with this (replace path1 with paths of folders that contain disk images, separated by...

A CD has multiple "slices": diskutil list /dev/disk18 /dev/disk18 (internal, physical): #: TYPE NAME SIZE IDENTIFIER 0: CD_partition_scheme *755.4 MB disk18 1: Apple_partition_scheme ⁨⁩...

My serial cable notes at #10

Old World Power Macs have a Serial Test Manager (STM) On a Power Mac G3, it has a menu and prompt like this: > *************************************** * * * Serial Test Manager * * *...

The default boot-device is disk2:aix disk2 is a devalias for /bandit/53c825@11/sd@2,0 The default diag-device is cd fd:diags which I guess is a list of devices? I'm not sure how to interpret this because cd is not a devalias. It appears that cd is a special device that initiates a search for a...

Is it the first of these? 1987-03 - 97851DB6 - MacII (800k v1) 1987-12 - 9779D2C4 - MacII (800k v2)

My suggestion of creating an Open Firmware script to patch the firmware won't work if you can't boot into Open Firmware. Startup the B&W G3 with the programmer switch held down as if you were going to perform a firmware update (read the firmware updater instructions from Apple). Let go of the...

Apple II sound is 1-bit but it's not just a square wave. There's same oscilloscope captures in this video:

The firmware updaters from PowerLogix and Sonnet for G4 upgrades do not appear to be in the form of an Open Firmware script so they cannot be applied from Open Firmware. https://www.sonnettech.com/support/kb/kb.php?cat=317&expand=_a3&action=b153#b153 Apple's Firmware Updater (to upgrade to...

@startvec.>'excp stores the default exception handler which is _exception This does a throw of the exception vector number. Maybe it can be replaced by something that saves more info (copy all the registers and the stacks?). @startvec.>'syscatch stores the default catch handler which is...

I have a Trace for Open Firmware script that can show what's getting executed. It needs more work but can do some simple stuff. It works by patching every word or words that you explicitly ask to patch. Then when you enable tracing, it will output each word as it enters and exits, and displays...

The nvramrc script and nvram variables that get modified by classic Mac OS are stored in OFpt resources in the Startup Disk control panel. 'OFpt' (128, "PowerSurge") 'OFpt' (129, "PowerExpress") 'OFpt' (130, "Gossamer") 'OFpt' (131, "PowerMac G3") 'OFpt' (132, "Wallstreet") 'OFpt' (133...