MaciNap is a small PCB which shuts down the analog board and slows down PWM fans when the screen is blanked.



Screensavers prevent CRT burn-in, but won't save your analog board or flyback transformer.

MaciNap monitors the video signal and shuts down the analog board once the display has been blank for about three seconds. When resuming from sleep mode, the video signal is suppressed until the sweep circuitry stabilizes, to avoid bright lines on the CRT. Power consumption is typically reduced by half during sleep mode.

A single amber LED on the board indicates status:

• Bright - Video is active and the analog board is powered.
• Two flashes - Video signal is dark and analog board is shut down.
• Dim - CRT protect: analog board is starting with video signal suppressed.

MaciNap generates two fan PWM signals which have a duty cycle of 100% when video is active. During sleep mode, they're reduced to 50% and 75% duty cycle, reducing airflow and noise.

The PCB intercepts the red wire on the PSU/AB harness (12V sweep). The video signal is tapped from the back of the analog board with a black/white twisted wire pair. The yellow and black pair shown here powers the Noctua PWM fan. The fan's blue PWM wire is soldered to the MED pad for speed reduction:




Basic through-hole soldering skills are required for installation.
Any screensaver which completely blanks the screen will activate MaciNap's sleep mode.
Basic Black is a lightweight screensaver recommended for System 6 and 7.

Available on Tindie as a 2-pack.

Fantastic idea!

QUESTIONS:

1. If I open Photoshop 1.0, 4.0, etc., create a 100% black screen and display that full screen for more than 3 seconds, does your device kill the Analog Board?

2. How long (approximately) does it take for the sweep circuitry to stabilize? What's the typical "wake time"?

Thanks!

>> JDW said:

1. If I open Photoshop 1.0, 4.0, etc., create a 100% black screen and display that full screen for more than 3 seconds, does your device kill the Analog Board? Click to expand...

Yes. Whether Photoshop, HyperCard or other full screen application, it will begin counting down once the screen is totally dark.

>> JDW said:

2. How long (approximately) does it take for the sweep circuitry to stabilize? What's the typical "wake time"? Click to expand...

It takes less than a second to stabilize. Suppressing the video signal during this time doesn't extend the wake time, it just prevents bright artifacts that might lead to burn-in over time. The analog board is powered immediately when a bright pixel is detected. From a cold CRT, it typically takes 4-5 seconds between moving the mouse and seeing a picture emerge; about the same as booting from a cold start.

It works great on my passively cooled MacEffects clear SE. I don't feel guilty about leaving the machine on and it's ready to use in seconds.

So because the motherboard remains powered, any software that can remain running while also keeping the screen 100% black could benefit from this, right?

Few will probably use an SE or SE/30 as a server, but I'm just curious if that is one example use case that may see a nice power-consumption and heat generation benefit.

>> JDW said:

So because the motherboard remains powered, any software that can remain running while also keeping the screen 100% black could benefit from this, right? Click to expand...

Right. During long installs or Stuffit operations, the analog board can shut down and the fan can reduce speed. For development or creative work, it's nice to return to your workspace as you left it, day after day. Same for games where you can't save your progress.