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Warning! Exploding Maxell PRAM Batteries

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I've got 3 IIgs's and the Limited Edition one has the battery on pigtails under the PSU, the other two have em in a different location in a plastic holder. And of the SE's, my old dual-drive SE and my current SE Superdrive had the soldered-on pigtail batteries too, but dad's SE FDHD had a removable Tadiran battery dated 88.

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and the II series had to have good batteries to turn the PS on? if i remember correctly...

 

Yep. The II, IIx, and IIfx use two batteries, one for the softpower circuit, and one for the PRAM.

 

I've got 3 IIgs's and the Limited Edition one has the battery on pigtails under the PSU, the other two have em in a different location in a plastic holder. And of the SE's, my old dual-drive SE and my current SE Superdrive had the soldered-on pigtail batteries too, but dad's SE FDHD had a removable Tadiran battery dated 88.

 

Sounds like the two with the plastic holders might be ROM 3 machines, or late ROM 01 machines. My old IIgs upgrade kit machine (ROM 01 version - board installed in June/July 1989) had the soldered Tadiran. Wonder if your SE Superdrive machine has an earlier board with the updated ROM chips. Both my original SE (a dual FDHD machine) and my current SE Superdrive had/have the removable batteries.

 

-J

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That's what I thought. Couldn't be certain, though. Yeah, one of my old 800K SE's was still trucking away, on its original Varta. Kept time, settings, everything. Was rather surprised.

 

-J

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still has its original VARTA brand battery holding a charge after 25 years.

 

Yes I have also seen this, was very surprised still had its charge. Forget what machine it was in. Pretty sure it was a Macintosh SE.

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What is your experience with the 'Saft' battery?

 

Saft-LS14250.jpg

 

They seem to be what RE-PC here in Seattle sells. Last time I used the G4 DA, it seemed to be fine, time-wise. Battery was installed prior to my buying the machine in early 2009. Was a LS14250.

 

-J

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My turn ...

 

mini_982114IMG2434.jpg

 

Scared by this thread, I decided to remove dead batteries from the most easily accessible in from my collection.

I removed 12, only 1 leaked, guess what brand it was...

It was in my PM 8100/80. Even the optical drive has signs of corrosion :O

 

Funny, the exploded/leaked Maxell battery was the newest of the 3. It had an expiration date reading 1993, while the two other had 1989 and 1990.

 

Those Sonnenschein Lithium batteries (the blue ones) seem to be reliable anyway.

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Another tragedy discovered today...

 

Quadra 610 and 660av didn't make it :'(

 

798084IMAG0383.jpg

The mess was still liquid in the Q610 :

596719IMAG0384.jpg

 

 

Funny though, another soldered Varta battery from a Mac II still showing some charge

749568IMAG0386.jpg

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That's a real shame! :( Hopefully you'll be able to use some bits as spares.

 

Btw I believe the date printed on the batteries is the manufacturing date, not the expiry date. As far as I know expiry dates on batteries were only introduced recently.

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Found one of these things in my Yikes G3…

 

Compared to the other brands, the Maxell one has a longer + Contact, and less battery… Could that somehow be the cause of these exploding batteries?

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I don't think storage conditions have much to do with it, though heat does speed up chemical reactions, so warmer conditions may speed it up a bit. Honestly I'm surprised so many of these cells *don't* leak after so many years. It's remarkable that one could go 20+ years without leaking the caustic stuff inside. Personally I would not leave a battery more than 5-6 years old in a system. 10 years is pushing your luck, longer than that is just tempting fate. If the machine will be stored for a long period, just be safe and pull the battery. It's not like there are a ton of settings that need to be restored.

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I forgot about the D cell batteries I had in my flashlight, they are 4 years old, leaked solid so i had to toss the flashlight. lol. So its amazing anything doesnt leak at all after 20+ years.

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I bought a stereo receiver off of ebay which still had the original batteries in the remote and in the receiver for memory backup. The unit was likely put into service in 1986-87. Batteries didn't leak and the remote still worked enough to turn the unit on/off!

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The replacement board arrived today, but it was so poorly packaged that it was damaged during transport: ><img src='https://68kmla.org/forums/uploads/emoticons/sad.gif.fd4612761a7f036f230186185c887adf.gif' alt=':('><

 

A chip and a cap were floating around in the box :

520801IMG2464.jpg735238IMG2465.jpg 317762IMG2468.jpg

 

They come from the areas in the yellow and red circles.

974470IMG2466.jpg

 

Great. Now I'm stuck with two damaged boards. Repairing is not an option since my soldering skill is... Zero.

 

Sorry for being off topic, but I wanted to share this "experience". :disapprove:

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Those caps are shot anyway, you can see the leaked electrolyte, the corrosion is why those parts fell off in the first place, look at how black that solder looks. Even if it was well packed, it would still need to be repaired.

 

Any board you find will need to be re-capped, so if you can't solder yourself, you'll have to have someone else re-cap the board for you. Those old SMT electrolytics just don't last very well, the old ones have all dried out or started leaking. This particular board looks like an easy fix, just clean it up, re-cap and solder that oscillator back on.

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