Dead G3 Powerbooks—Any Way to Test the Screens?

I have three dead Pismos that I got as part of a possibly ill-advised purchase of a bunch of Macs off eBay. I had hoped they were easily fixable, but nothing I’ve done has brought them back to life. As such, I’ve decided to part them out. The most valuable part of each one is probably the screen. However, I have no way of testing them. Any ideas how I can test whether they’re working or not? I have a pair of Clamshells I can take apart if needs be to try and test the screens. Any ideas if this would work or, failing that, any other way to test them?

Many thanks.

Have you verified the Pram battery is good?

Pismos will appear dead if Pram battery is completely dead!

I haven’t been able to verify if it’s the PRAM battery or not. I have no idea of how to test it, and I’m reluctant to spend another £23 (not including shipping) on what may turn out to be dead Pismos.

Any ideas on how I can test them? I could always try switching them around to see if that makes any difference: they were dead before the HDs and RAM were taken out, so I suspect that—if it’s the PRAM battery causing the issue in one or more of them—all the PRAMs will be dead.

Alternatively, any idea how to replace it more cheaply, or make my own?

Try Headgap.com

They carry Pram batteries much cheaper and new!

Refurbished Used Mac Systems, new and used accessories - Operator Headgap Systems Inc.

You can test a pram battery by putting a paper clip in side of the connector and licking the paper clips. If you feel a mild shock it is still good. If not, it is dead. This is similar to testing a 9V.

Sorry for the late reply—my attention wandered somewhat, and I forgot about this thread. I'm going to test all three PRAMs using the method you suggest to test them for signs of life.

On a related note, I came across an eBay auction for a Pismo that says you can actually run the Pismo without a PRAM at all. Is this the case?

Yes, boot from a cold dead start, wait for the chime, then Apple/Option/P/R and hold them till the next chime. That zaps the pram of course, it should allow you to boot. I have seen many Pismos too damaged to boot correctly, but if you startup in Target mode you might find the screen works fine.

Thanks for that. I tested it out, and I have two working Pismos now (which is what I hoped for). I’m writing on one of them right now!

Many thanks to all the posters in this thread—your help was much appreciated.