compact mac preservation

[nahuelmarisi]

I know there have been some threads related to batterries and compact macs, and if they should be removed for storage, so forgive me if I'm repeating myself.

I have quite a few compact macs, and unfortunately due to limited space I have to store about half of them. Besides the obvious advice of having it in a dry area, I was wondering what's the best to preserve it in working order.

Ie, is it a good idea to turn it on every now and then? If so, how often. Does storage increase the posibility of leaky capacitors or other faults?

I mainly have everything from the mac plus up to store

 

[Mac128]

Personally, I would remove all batteries and store them away from high heat (the same is probably true for extreme cold as well). If they are packed inside a box there is no ventilation and they will just heat up and cook themselves based on the ambient temperature of the storage area. A dark cool closet is best. In some cases I have actually removed the logic-boards and stored them in static bags in a cool location as they are smaller and take up less space than the case itself. cCassic Analogue boards are actually the most susceptible to heat, but also more complicated to remove from the case and store like that, although not a bad idea either and think I will!

 

[nahuelmarisi]

Do you think that it's a bad idea to put the mac on a box? Ie, would it be better for it to have ventilation?

 

[Mac128]

What's the choice? You don't put them in a box or garbage bag and they will just collect dust or get knocked around in your storage area. I think the best bet is not to store them at all and find a way to display them, in a Mac shelf for instance as art. This of course is not always practical, so you mitigate the effects of storage as much as possible. Long term storage? Put them in boxes, store the heat susceptible components separately in more controlled environment if possible. Or sell the more common ones on eBay knowing full well you can easily replace them one day from eBay when you are in a position to display them and use them. Put the proceeds from eBay in a Mac fund and don't touch it and you'll have even more money to play with later.

 

[Scott Baret]

Put them in the original box if you have it...it's worth more!

Avoid the attic. Keep them at room temperature. Don't put them in the garage if it gets too cold in the winter.

 

[equill]

If the cost of electricity is not a concern to you, and if you have no commitment to extreme notions of ecological responsibility, store your working Compact AIOs indoors on shelves, attached to the mains but not turned on, so as to maintain trickle power. That results in battery life equivalent to their shelf lives, and minimizes the temperature extremes that outdoor storage may induce.

I have more than thirty Macs from CRT iMacs to Compact AIOs in my study (in a temperate coastal climate), and all of them are functional. More than twenty are in a LAN and ready for instant startup. Non-functional Macs I keep without power or batteries in an outdoor brick garage.

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[Scott Baret]

If you have to use shelves I recommend the heavy-duty blackish-greyish Closetmaid shelves. I have some of these in my garage and store extra equipment on them. Right now I've got an SE, a monitor, a big old Compaq, and a few printers on those shelves with no signs of sagging.

They're easy to put up as long as you have the right drill bit. These are good for stuff you aren't preserving for aesthetic appearance but just need to get off the ground.

Of course, if I'm doing something in the garage like washing a car or doing a lot of sanding at my workbench, I cover the computer stuff with an old blanket that used to be my dog's. This also keeps them relatively warm so I like it when I'm going to be keeping the garage door open for a while in the winter, or if the lows are so low that they need extra warmth.

 

[TylerEss]

store your working Compact AIOs indoors on shelves, attached to the mains but not turned on, so as to maintain trickle power.

Note that this (awesome) advice applies only to the Color Classic and Color Classic II (based upon my definition of "Compact AIO"). All the black-and-white Macs from the 128k to the SE/30 and Classic II use hard-power, and there is no trickle power on them.

If it boots immediately after turning on the switch, it uses hard power and gains nothing from being plugged-in-but-not-turned-on. If you have to press the keyboard power key, it uses soft-power and gains extended PRAM battery life from being plugged-in-but-not-turned-on.

 

[Scott Baret]

Don't forget the pizza box LCs in this. They also used hard power. Just a tip if you're keeping something other than compacts in your general area.

 

[equill]

... Note that this (awesome) advice applies only to the Color Classic and Color Classic II (based upon my definition of "Compact AIO"). All the black-and-white Macs from the 128k to the SE/30 and Classic II use hard-power, and there is no trickle power on them ...

My slip of the keyboard, sir. [Pulls forelock.] I wrote 'trickle', which you took to mean TRKL (5V), when I should have written 'dribble', hereinafter referred to as DRBL (5V).

TRKL is an indispensible facet of soft-power management, as all of us who suffer from the Astec villains of the IIcx/IIci/Q700 gang well know, and not confined to just those Macs. In the CCs, because they also have an on/off mains switch behind, it is a variant that Apple calls pseudo-soft power, but that doesn't diminish what TylerEss wrote.

In complete distinction is DRBL, which I did mention in a prior post by its 'correct' name, here. It is the reason why PRAM batteries in desktops can last as long as their shelf-lives in Macs that are permanently connected to an active mains supply.

The effect of that was adequately summed-up by Allan Jones, here:

'On any Mac, PRAM battery life is hugely extended by leaving the computer plugged into wall power at all times. A trickle of power bypasses the power supply to power the PRAM even it (recte: if) the computer is turned off. If you unplug or cut the power at a power strip, the battery has to do all the work to maintain PRAM information and the battery life can fall from years to months.' Apart from Allan's and my having (seemingly) read the same books and looked at the same circuit-diagrams, I have found, unfailingly during the last 20-odd years, that it works.

It could be added that, in the case of say, iMac CRTs, if resetting the PMU is mismanaged, that lifetime reduces even further, to overnight. A pain, but not the fault of the battery.

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[TylerEss]

In complete distinction is DRBL, which I did mention in a prior post by its 'correct' name, here. It is the reason why PRAM batteries in desktops can last as long as their shelf-lives in Macs that are permanently connected to an active mains supply.

I have found, unfailingly during the last 20-odd years, that it works.

If it works, it works, and keep it up.

For curiosity's sake, I did a few little experiments with a Mac LC, SE/30, and LC575 and Classic analog boards ('cuz I've got the 575 and Classic analog boards but not whole Macs right now).

In the Mac LC, there is no voltage between ground and any other pin of the power supply output when the switch is switched off. Opening the case of the PSU reveals that the power jack is connected directly (and only) to a DPST switch, and the switch then connects to the PSU circuit board.

I didn't open the SE/30 PSU (becuase it takes lots of screws to extract the PSU from an assembled SE/30) but I did test the voltage on the pins of the motherboard power/video connector: when the mains switch is off, there is 0.00 volts between ground and any other pin on this connector. I'm fairly certain we'd find the same switch-wiring inside this as the LC PSU.

The LC575 Analogue board, like the color classic analogue board, has the mains connector wired directly and only to a DPST switch, which then goes to the analoge board; this is pseudo-soft power, and as long as you leave the switch on but the Mac shut down, you will gain the advantage of TRKL keeping your PRAM battery alive.

The Classic analogue board also has 0.00 volts between ground and any other pin of the motherboard power/video connector when plugged in but switched off. The mains connector is PCB-mounted, but a quick look makes it seem like the hot side of the mains connector goes to the SPST power-switch before getting into anything useful on the analogue card.

I don't have a Mac Plus to look at or test, so it still may be possible that they have some sort of always-on trickle/dribble voltage.

My tests, both circuit inspection and voltage testing, do not reveal any kind of PRAM-prolonging always-on voltage in any of the Mac LC series, SE/SE-30, or Classic/Classic-II.

The Color-Classic and similar AIOs with power switches do have trickle power, but only when the switch on the back is left on. Don't switch off a CC!

 

[equill]

I can speak with direct experience (because they are nearby) of the passive power-control, or, in Apple's parlance, 'pseudo-soft power-on', in the CC/P250, 5400, 5500 and 580. Out of the box or the cupboard where they have not been powered, the top of the case bucket, at the rear, is 'cold', or at the same temperature as the rest of the bucket. Mine have been powered-on through the rear case switch since they were set up anything up to five years ago.

It's 25°© in my study at the moment, near the end of a night of intermittent rain, with cool saturated airflow through the room. All the Macs are palpably warmer above that rear case switch than in the rest of their cases, the CC/P250s more obviously so because of their smaller dimensions. The palpability is greater during our winter, when my study gets down to 8-12°. It is just as real for the (again, passive power-control, but with no kind of soft power-on) Compact AIOs 512Ke, Classic II and SE/30 that are set up ready for switch-on as it is for the spare Classic, Classic II and SE/30 sitting, with active mains connections, on the shelf behind. The warmth is not so discernible atop the pizza-boxes of the LC II and Q605.

The dozen-odd active power-control Macs, with true soft power-on, that are also in the room are always warm, and this is most apparent in their PSU cases immediately after the Macs are opened, or in the vent area of the CRT iMacs. To the extent that their startup circuits are represented by the schematics for members of the Mac II family, it is very clear that a normally reverse-biased diode protects the 3.6-V PRAM battery from the 5-V supply to the relevant pin of their clock and PRAM ICs, PMUs or whatever.

I suspect that the battery-sparing in the Compact AIOs will be far more readily revealed as a minuscule current consumption by the powered-off Mac. In the PSU schematic for the SE and SE/30 (Bomarc), the PRAM battery is again shown as protected by a reverse-biased diode from a 5-V supply, in the absence of which it provides power on a 4-V line to the real-time clock/PRAM IC. That revelation was not the least of my reasons for getting hold of the SE/30 schematics when they were offered here Before The Fall, but only this thread has stimulated me to seek out whatever is to be found. I have yet to track down the source of the 5V (the schematics are in .pdf), which is, of course, the nub of this part of the thread. Hold your breath for a later revelation.

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