Manuals for a PISMO

[Dglas]

Anyone know where one can find manuals.

I just picked up a PISMO and would like to have a user manual and/or a repair manual. It has a dead main battery and the pram has been disconnected - I assume it is dead also. Unit works fine on the AC connection although it seems like I have to hold down the start button quite a long time before it starts to boot up. Also when a CD/DVD is operating it can vibrate and make a lot of noise. The noise can be stopped by simply holding light pressure on the door. For the time being I will get a new pram battery and simply operate plugged in to the AC. I am not familiar with the computer and will need to get advise on replacing the pram battery.

Does the pram battery have any other function than the date/time?

 

[Dennis Nedry]

The PRAM battery in pismos is rechargeable. It recharges after the main battery is full. It should be possible to operate with a dead PRAM battery.

The long time necessary to hold the power button is probably because of the dead PRAM battery.

The noisy DVD drive may be normal. For me some discs are loud and others are okay. Maybe the disc isn't perfectly round/balanced.

 

[beachycove]

Backup (not just pram) batteries have several functions in a powerbook, so that it is unwise to rely on a powerbook without a functional backup battery. The Pismo in particular will commonly refuse to start up without a functional backup battery, or without the discharged one being disconnected. You can, of course, still dabble away like you are already doing.

Before digging too deeply into your pockets for a new backup battery, shut the machine down normally, take the main battery out, remove the keyboard and plug the backup battery leads back in. Leave the machine plugged in overnight or even for a couple of days, WITHOUT THE (DEAD) MAIN BATTERY. The backup battery will often revive in this way, since it will not recharge if a dead main battery is inserted into the machine (it seems to wait for that to finish first, and of course it never does).

User Manuals can be downloaded from Apple. Service manuals are more difficult to find, but can sometimes turn up on Carracho/ Hotline servers and the like.

 

[Dglas]

Thanks Guys for the advise. I have removed the main battery and plugged in the pram battery and plugged in the charger. I will leave it on overnight and see what that does.

 

[Dennis Nedry]

Backup (not just pram) batteries have several functions in a powerbook, so that it is unwise to rely on a powerbook without a functional backup battery.

I've heard this before but didn't really take it seriously. What does this battery do other than the battery in an ordinary desktop Mac?

I'm especially curious because I have a Pismo that I use all the time.

 

[beachycove]

The backup battery is powerful enough to maintain a powerbook in sleep mode for as much as a couple of days; they are rather robust when functional, in other words. The way the power settings are programmed to work, furthermore, is that the machine expects there to be reserve power when the main battery runs out of juice, so that the machine automatically goes to sleep and switches to the backup cells. On some models, it is true, it appears that a dead backup battery has relatively little effect, beyond the loss of pram settings on removal of power. On others, including at least some Pismos, a dead backup battery can cause an anomalous refusal to do anything at all when the attempt is made to power on. It is standard practice in reviving a "dead" Pismo, therefore, simply to disconnect the leads of a dead/ discharged backup battery as the first step in diagnosis and recovery, since it is common experience that a supposedly "dead" machine will power up once the source of the trouble (the backup battery) is removed. Many "dead" Pismos one finds listed on eBay are not dead at all, and many are new enough to have perfectly functional backup cells that just need a little TLC to be revived. My Pismo came to me in just this state.

It would seem from this that the Power Management subsystem relies on those backup cells, or at least, that it can be easily corrupted without their being in working condition. Why these Pismos will start up with no backup battery at all is anyone's guess: residual power that just confuses matters, perchance?

I have in the past had some duplicate Duos, some with functional backup batteries and some without; those with functional backup batteries were (and are) rock solid machines, whereas those without have behaved erratically. You could boot one of them, but in use there could be anything from random shutdowns to episodic GLOD to refusals to reboot and so regular reset requirements to deal with. All this is best avoided, unless all you want is to tinker with a machine once a year when taken off a dusty shelf.

There are some characteristically informed posts around and about from equill on this subject, as I recall, that might be ferrited out for reference. There are also some useful posts on Apple's Support/ Discussion pages and other sites such as the old Duolist that appear when GLOD is researched.