Beige G3 chimes with no picture for a long time before showing grey screen and booting MacOS. Black screen duration is proportional to installed RAM.

[theirongiant]

I have a beige G3 233MHz (Rev A? ROM $77D.40F2) that I picked up from someone locally. It had 96 MB of RAM, so I decided to upgrade it and install OS 9.0.4.

When it has less RAM, the computer chimes and shows a black screen for maybe 10 seconds before going gray, then showing the happy Mac.

I sourced 768 MB of RAM (3x256 low profile DIMMs) and installed them one at a time. With 256 MB of RAM, there is no picture for about 40 seconds. With 768 MB of RAM installed, this delay extends to about a minute and a half.

The following cards are installed (removing them had no effect):

- PERCH: Standard audio card
- PCI: USB+FW combo card with TI & NEC chips (featured elsewhere on this forum)
- PCI: ATI Rage 128 (sourced from a blue & white G3)

I realize that all computers have a RAM test as part of their POST routine.

Is this duration of black screen normal for a G3 beige Mac doing a power-on self test?

I ran some utility recently that shows the PRAM hasn't been reset since 1998, and the 3.6V lithium battery is still working and keeping time. Would resetting the PRAM change this behavior at all?

Another colleague recommended that I press Opt-Cmd while clicking the Memory control panel. This reveals a hidden option to disable "Startup Memory Tests." I've turned it off, but it does nothing.

Also, if I restart the Mac (instead of shutting down), the following sequence occurs:

1. Hard drive spins down
2. Monitor goes black
3. Boot chime
4. Black for X seconds
5. Gray screen
6. Hard drive spins up
7. Happy Mac icon, boot

Thanks!

 

[Chuckdubuque]

That’s normal with that amount of RAM. The boot process does a RAM check. My G3 takes an unsettling amount of time when testing RAM.

On the 68k Macs like the SE/30 whose contemporary max was 8MB but with more modern RAM can support up to 128MB, there are ROMs that bypass the RAM checks to speed up boot. I don’t know if there are similar ROMs or ROM patches for later machines.

 

[theirongiant]

That’s normal with that amount of RAM. The boot process does a RAM check. My G3 takes an unsettling amount of time when testing RAM.

On the 68k Macs like the SE/30 whose contemporary max was 8MB but with more modern RAM can support up to 128MB, there are ROMs that bypass the RAM checks to speed up boot. I don’t know if there are similar ROMs or ROM patches for later machines.

Ok, so now I really want to know why this trick works and skips the RAM test:

https://68kmla.org/bb/index.php?threads/beige-g3-strange-issues.31644/post-337746

In my testing just now, I only had to wait about 1 second after the chime was inaudible before pressing ctrl-cmd-reset, and boom ! The G3 displays the gray screen in about 10 seconds and starts booting.

That's a massive improvement with 768 MB RAM installed.

edit: if I boot the Mac with this startup hack, a subsequent Restart will be just as quick, as if my choice persists in memory until power off. A full power off then power-on will reintroduce the delay.

 

[Byrd]

Having a good PRAM battery will retain the bypass memory check each boot

 

[theirongiant]

Having a good PRAM battery will retain the bypass memory check each boot

...but would this be retained after a full power down? Or just a restart ?

 

[nathall]

Restart only.

 

[aladds]

For bypassing on every boot, open the memory control panel with command and option held down, then turn off the new option at the bottom