Power Supply "pass-through" question

[beachycove]

This is a odd question, but there's method in the madness.

I have been experimenting with the pass-through power connection (for the monitor) in the power supply of a few of my older Macs. I will call this the monitor power ("mp") in what follows. I have observed the following:

A 7200, 7500 and 8600 supplies "mp" when on or asleep, and no "mp" when turned off. I seem to recall that the beige G3 power supply has "mp" on all the time, but I have not done any recent testing, having seen this behavior with monitors needing switched off with the G3 for years.

It might help to explain why I have been looking at this. What I thought I might be able to do is run a LaserWriter printer from the "mp" connection, but have it powered down when the Mac is asleep. Then, when I need to print, I would wake up the Mac and the printer with it via an Applescript doing WoL remotely (wake-on-lan, possible with a suitable pci ethernet card installed). The pages would print; then the machine would go back to sleep automatically, with the printer, after 30 minutes or whatever via energy saving settings, i.e., when printing was done. Basically it would give an old Mac a useful job to do on a daily basis, and stop the youngsters turning on a large LaserWriter, leaving it running, and ramping up my power bills. Old printers do not have the energy saving features of current technology, and tend to consume 60w or so when running.

However, none of the machines tested shut off "mp" when asleep, which I find a little odd.

Now, these tests were done with a LaserWriter connected, rather than an energy star compliant monitor. It could be the machines would behave differently with a monitor connected.

Am I right about this, and is there any way of doing what I want via a PCI Mac?

 

[Trash80toHP_Mini]

Why does your print server need to go into sleep mode instead of just shutting down and booting back up for print jobs? Booting it up remotely can be done a few different ways, IIRC. Having it shut itself and the printe down after a set period of inactivity would be duck soup, IIRC. Back in the day I used a PowerKey Remote(?) to boot up the Tandy 1000SX w/JT-FAX Card and the printer whenever a FAX came in wqhen I wasn't in the shop.

The Macs don't shut down mp because they're expecting an Energy Star m to be p'd. It's a simple relay setup in the PSU to implement mp, no intelligence is involved to detect anything at all.

 

[beachycove]

... a simple relay setup in the PSU to implement mp, no intelligence is involved to detect anything at all.

So my next question: Is the ps meant to shut mp off completely or just to supply mp at a reduced level, sufficient for keeping the monitor warm for "instant on" behaviour?

 

[Trash80toHP_Mini]

AFAIK, when you turn on the power to the computer, the relay supplies power as long as the PSU/Mac is powered up. Sleep doesn't change the equation, pm is either on or off depending upon that one PSU state.

 

[onlyonemac]

For your project, you could add some sort of USB, serial, or PCI controlled card with a two power connecters on it. One is connected to a power supply, and the other to the printer's supply input. The card would have a relay to switch the printer power on and off separately to the mp. You could program some sort of script to tell the card to power the printer up, then another script could kick in to print the job, and finally a third script turns the printer off again.

 

[beachycove]

Could do, but that would be complicated and is certainly not the quick fix I was looking for. Easier just to start up the printer conventionally, by walking downstairs and powering it on. Or indeed, I could just get a wall switch with a timer!

Ho hum, no use for another old Mac there, then.

 

[Trash80toHP_Mini]

I use the radio controlled power switches for Christmas lights, usually about 15-20 simoleans for three 15A RC switches w/one controller.

 

[beachycove]

That's an interesting option.

I found this document in a trawl just now, which basically says that the energy saver feature worked in this respect by cutting the sync lines rather than by shutting off power. Though that document pre-dates the PCI Macs, they likely operate on the same basis, which would explain what I got and why I got it in my trials.

 

[Trash80toHP_Mini]

I used to use X-10 to run just about all the utilities in my shop:

- three banks of shop lights

- shop vac for the vacuum table

- exhaust fan

- compressor

- dust collector

- A.C.

I could call ahead and start up the A.C. by phone. ;D

 

[markyb86]

I skipped a little bit, but I just want to add that my B&W and G4 Sawtooth towers both leave the pass-through on at all times. My SE is powered off of the G3 when it is off. And my G4's monitor never shuts off by itself. (OOOOOOLD CRT without sleep)

 

[CelGen]

Bit late but I'm just trying to figure out what you want:

Computer off: Printer off

Computer on: Printer on

Computer on but in sleep mode: Printer off.

The easiest thing to do is see if when the computer goes to sleep the PSU cuts power to all the drives or if it just tells them to spin down. If the former it's a simple relay solution but if it's the latter you need a bit more work running a transistor off the spindle motor power on a hard drive to open/close a higher voltage relay circuit.

...or poke around with a DMM and see what on the computer loses power when it goes to sleep.

 

[beachycove]

A little more testing with the machines I have available tells me that a Centris 660av, oddly, is like the G3: "mp" is ON whether the machine is awake, asleep or shut down. However, a IIsi nicely turns "mp" off when it is shut down, and (with the Auto-Power Control Panel installed) is capable of automatic startup and shutdown at specified times. Same with a IIvx/Performa 600, and maybe a IIvi (though I don't have one to test). The IIcx, IIfx, and IIci can do some but not all of this, and obviously the Compacts and LCs can't, so at this point the humble IIsi has a niche feature set among the pre-Quadra machines. The Quadra 650, 800, 950 and 840av also behave like the IIsi, but they are best used for more exalted tasks than I now have in mind.

So I think what I'll do is just use a IIsi, as it is smaller and much more energy-efficient than the PCI Macs with which I began. The method in the madness will be as follows: I'll set the IIsi to automatically start up and shut down in the timeframe when the youngsters need to do their homework printing, connect the LaserWriter to it for power, and let the IIsi do some simple home automation. That will work well enough. I think I will also run a second hard drive in the IIsi, which has room for it, connecting it to the SCSI port of the LaserWriter in question (a LW Pro 630) for storing TrueType fonts that aren't in the old gal's ROM. This is a seldom-used feature of the older LaserWriters, requiring use of the Apple Printer Utility, but it is said to speed things up — much needed with a printer running an '030 processor. Too bad I can't make the IIsi do some postscript processing in combination with the printer!

Why do this? The cheapest of all toner can be had for the printer in question (HP92298x, findable at $30 for c. 9000pp. of output), and these printers just go on and on like tanks. I also like to find a use for old gear, largely because I am able in this way to thumb my nose at the disposable culture. I am not sure that I could exactly be said to be "reducing" with all the old stuff I have around, but I certainly do reuse, and recycle when there's nothing else for it.

 

[beachycove]

I think I will also run a second hard drive in the IIsi, which has room for it, connecting it to the SCSI port of the LaserWriter in question... (a LW Pro 630)

And that's not going to work. Tried, failed, and looked it up: External SCSI devices connected to the LW Pro 630 require one of the black IIfx terminator plugs, which I don't have. Ho hum.

 

[CC_333]

And that's not going to work. Tried, failed, and looked it up: External SCSI devices connected to the LW Pro 630 require one of the black IIfx terminator plugs, which I don't have. Ho hum.

Won't connecting the printer to the end of the chain work to circumvent this problem?
Good job with reusing stuff, by the way; I can't seem to come up with a use for much of anything (and it therefore sits around collecting dust).

c