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Check those batteries yearly...

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framer

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Nov 27, 2008
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Murrell's Inlet SC
I got a little lazy and had not changed batteries in my old AT's 386's and 486. I've removed all the original NICDs and have been using AA batteries in a holders for years. Anyway it was sereral years ago that I changed the batteries and when I was servicing a 486 I noticed leaking which killed an NIC card. I've now gone though the rest of my machines and put new cells in all the holders.

Tip before changing batteries turn the machine on and enter your setup and write down any info that you will need to re-enter if your CMOS data gets trashed. Yes, I forgot to do that on my 1st fix.

framer
 
framer said:
Tip before changing batteries turn the machine on and enter your setup and write down any info that you will need to re-enter if your CMOS data gets trashed. Yes, I forgot to do that on my 1st fix.
Click to expand...
Why bother when you can use a CMOS Save/Restore program that will do that for you automatically? :)
 
It is much more difficult to mis-file, lose, overlook, or mix up a note taped to the inside of the case. Also handy if the dumb thing won't boot at all without the setting, although that isn't too common. And a note is fine if it is just a couple of settings.

I've had some weird bad luck with regular batteries. I've actually had AAA batteries in a remote leak all at once while I was actually using the darn thing.
 
I put my battery holders in a plastic bag taped, if possible, to the outside of the case. Good quality alkaline cells should last for at least 5-10 years. Off-brand garbage ones is a craps shoot.
 
Chuck(G) said:
I put my battery holders in a plastic bag taped, if possible, to the outside of the case. Good quality alkaline cells should last for at least 5-10 years. Off-brand garbage ones is a craps shoot.
Click to expand...

Same here for bagging them. I've had good luck with Energizer Industrial batteries for alkaline replacements, and Tenergy NiCd cells when I wanted rechargeable batteries.

As to saving/restoring CMOS settings, IIRC I use a program called CMOSER.
 
I refuse to even use AA cells because if them being so prone to leaking.
As for CMOS settings, all my machines have a post-it note somewhere inside with things like the drive parameters.
 
I haven't had to deal too much with leaking motherboard batteries as of yet ***KNOCK ON WOOD***, though I did clip the AA pack off the logic board of my Apple Lisa (which, fortunately, hadn't gotten too corroded). What has been the bane of my existence as of late, however, have been those damned Dallas Semiconductor DS1287 and DS1387 RTC chips. I have no idea why so many companies decided to rely on those stupid things instead of a more stout battery which could be replaced, and would hold the info longer than a simple coin cell epoxied inside an IC. What's worse is that both of these RTC chips have been discontinued, and replaced with new versions (DS12887 and DS13887) which might not work in place of the old chips. Overall, not a great decision by the manufacturers, if you ask me. :cursemad:
-Adam
 
All in all, it was a good decision. It got rid of the need for batteries on the motherboard and the lithium cell would last a decade.

A lot of these used a clone of the Motorola MC146818 chip (that's what the original 5170 used), and you needed a bit of external circuitry to keep it going.

I suspect that you can still find the naked DIP RTCs that these are based on and supply your own crystal and battery.
 
framer said:
I got a little lazy and had not changed batteries in my old AT's 386's and 486. I've removed all the original NICDs and have been using AA batteries in a holders for years. Anyway it was sereral years ago that I changed the batteries and when I was servicing a 486 I noticed leaking which killed an NIC card. I've now gone though the rest of my machines and put new cells in all the holders.

Tip before changing batteries turn the machine on and enter your setup and write down any info that you will need to re-enter if your CMOS data gets trashed. Yes, I forgot to do that on my 1st fix.

framer
Click to expand...

Keep the batteries away from the motherboard and cards. In my AT shape machines, I put it behind the drives / in front of the power supply. That way it will pretty much only damage the inner case if it leaks.
 
What about using those non-alkaline "heavy duty" type batteries? They don't seem to be as leak-prone, but perhaps that's because I've just not been around enough of them... I've just started pulling batteries out of everything I come across...but then again, most don't get regular use...

Wesley
 
When using AA's I like to put them in an altoids-type tin sitting flat whichever way the case will spend most of its time sitting, then seal it with gorilla tape. This way when/if they leak, they'll only leak in the tin. Just double-sided velcro in for ease of maintenance.
 
The carbon-zinc "heavy duty" batteries have a shorter shelf life than alkalines and are just as leak-proof. The real downside is that the leakage products are strongly acidic, which can make a real mess of things. Alkaline leakage is well, alkaline.

Why not use plain old lithium primary cells? If your application is low-drain, they should last a decade. And really, no battery has any business sitting on a PCB. As deathshadow says, put them in a container, even if it's only a plastic bag. It'll save you much grief.
 
Watch out for multimeter batteries too, I opened up my Simpson 260 last week due to not being able to zero the low ohms ranges (typical sign of a dead battery) to find the D cell starting to get crusty. It's easy to forget them!
 
For PC mainboards I remove rechargeable NiCD and, as they're usually around 3V, install CR2032 through diode to prevent charging non-rechargeable battery. To make CR2032 leak much more specific conditions must occur than with typical NiCD or AA.
The same thing I do with old notebooks CMOS keeping batteries, but before removing it, I take photo of battery and, if it is, cut the sticker off and glue in battery's place. So if I would need to install one, I will know what to look for.

Recently I got a Siemens industrial PC machine from early 1990s. It had "Varta Energy 2000" AA batteries in battery pack to keep RTC running. Batteries best before: 1993. Text "Made in West Germany" suggests that they have been manufactured before 1991. They still read about 1.33V and can power e.g. my wireless mouse!
Comparing to "Varta Industrial" I bought last year. Best before: 10/2016. I kept them as spare and recently peeked to the box: Two started to leak just by itself, and after tests, most had energy only to power wall clock for 2 days.
 
Some of the big PLCs used what amounts to a lead-acid motorcycle battery to keep memory alive. You lose that and reloading the PLC can take some effort and time.
 
If you're lucky you have the punched tape, it's intact, and the tape reader still works.
 
It's kind of surprising to see one of those systems that's put in 30+ years in the same shop, only to run into the "dead battery" issue after it's been moved to a new location. The last one I helped with used audio cassettes and a special tape drive to load. Believe it or not, said cassettes were still readable. I'm assuming that the cassette setup was an upgrade to a PTR.
 
I've got one5 that uses microcassette. The tape drive didn't work when I acquired it in 2002, but I somehow got it working. It doesn't work now and I'm not sure why not.

In 2005, I had to buy a very expensive tape drive emulator to get it to work. My goal at some point is to build my own emulator to replace that one; I don't like it.

Unfortunately for reasons I haven't figured out yet, the memory retention doesn't work, and hasn't since I got it. So every time I power on, I have to spend a half hour loading emulated tape. When I got it, there was a dead 5V lead acid battery the size of a motorcycle battery in it. I couldn't find a replacement, so I wired up a bunch of NiMH D cells for 4.8V. That turned out to be a waste of time though because even with a 5V power supplly connected, it doesn't work. I know I traced the battery voltage to the memory boards and it was working, but I never went any further with it.
 
Even checking them yearly won't help as they could leak the next day.

I have a lot of 386/486 machines which used to have the soldered in batteries and some of those started leaking. I unsoldered all those batteries and replaced them with AA battery holders. Unless I am going to use the machine all the time, I don't actually install batteries. For those machines which I boot very infrequently I just leave the batteries out and set up the BIOS when I power it on. Most have IDE Auto Detect and if they don't, I'll just write down the drive parameters. If I really get stuck with a drive, I just put it into a machine with Auto Detect to get the specifics.

Having had one set of AA batteries leak and get very close to the MB, if I use them I will be very careful to isolate them as much as possible.

Joe
 
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