Amiga hardware info, help and support with a focus (but not limited to) North American NTSC experiences. Open to all.
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Zippy Zapp
CA, USA

by Zippy Zapp posted Thu Feb 02, 2017 11:18 am

Amiga 2000, 3000, 4000 and A501 512k RAM all suffer from a common problem, the rechargeable RTC battery. It only really lasts about 6 years before it starts leaking corrosive battery acid all over your motherboard. The really bad thing about these stupid batteries is that if left untreated can pretty much ruin the motherboard. You see the battery acid flows along the copper traces and eats them up in the process. Depending on the model it can ruin, for instance, the RTC circuit and CPU socket of an A2000. The Amber circuit (VGA) of the A3000 and SIMM sockets on the A4000.

So if you still have these batteries clip them off immediately.

Replacements
They still do sell replacements and you can solder a new one on every 6 years or so. Or you could solder wires to the battery termials and to the motherboard and encase it in heatshrink or electrical tape or something and put it off the path of destruction. Then you need only solder on a new battery to the wires or use clips so you don't need to solder it every 6 years. This has the advantage of still using the recharging circuit built into the Amiga and the proper voltage of the RTC at 3.6v.

Here is a link to the actual battery used in the Amiga:
http://www.newark.com/varta/55608303059 ... p/06WX2749

Another option is to get a 3.6v cordless phone rechargeable battery pack and solder wires to the motherboard so the pack can stay velcroed out of harms way. These batteries usually don't leak and can last quite a long time.

Another option that I have seen is using a button cell replacement CR 2032 mounted on a circuit board that has a diode to negate the Amiga's recharge circuit as you do not want to recharge a CR-2032. Here is a link for that option:
http://amigakit.leamancomputing.com/cat ... ts_id=1093

I have read about people that use a rechargeable 2032 coin cell and let the Amiga Charge circuit charge it. Never do that as those batteries are not designed to be charged in the way the Amiga charges batteries. It could and probably will explode after so long.

Something I thought of recently as I had to replace a corroded battery on an old PowerMac was that you could use that 1/2AA battery that the Mac uses as long as you also use the diode to prevent charging. The advantage to these is that the voltage is the same at 3.6v. The CR2032 works but seems I recall reading that the lower voltage could cause problems with some RTC chips.

So what options do you use?
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intric8
Seattle, WA, USA

by intric8 posted Thu Feb 02, 2017 11:43 am

This is a really timely question for me, personally.

I've spent the last week (actually a bit more) going down this road with my functional 2000. My other, which is currently dormant and dark, is (I believe) the victim of battery acid damage the likes I can't personally repair. It's really unfortunate.

But for the working machine, I made it a mission a few weeks ago to replace the battery. I got the necessary soldering equipment and bought the coin battery option, which arrived from the UK in January. I went this route as I really liked the idea of using an easy to find and replace battery option. I mean, they sell these coin batteries at my local pharmacy. And the new option from Amigakit looks really nice and clean. And it's cheap!
IMG_6695.JPG
Lithium Coin Cell Clock Battery Kit
I was planning on making it a more fleshed out "How To" post. I pulled the entire 2000 apart and removed the motherboard. I then de-soldered the old battery stand and cleaned the motherboard thoroughly. Then I soldered in the new kit. Overall, it took up most of my Sunday morning a couple of weekends ago.

After buttoning everything back up again, I went into a bit of a panic. Long story (very long) short, my accelerator board - the CSA Derringer 030 - was contacting my drive bays and the very subtle angle changes caused all kinds of hell.
IMG_6702.JPG
New battery in place.
IMG_6707.JPG
New battery, seen from the bottom of the motherboard with new solder.


After a couple of days, I finally got everything working again. Except, the battery I replaced still isn't saving the date and time!

Using SysInfo, I can see that the machine sees the IC just fine. If I set the date/time in Prefs (or DirOpus, or CLI) the 2000 will keep track of time while the computer is on. But I think a trace from the battery pots must have a break somewhere, as the battery can't hold what's in the IC.

Super frustrating. I even threw a hail mary with Thomas' RestartClock program, but that didn't work, either. I think that is mainly for "waking up" stuck IC's, but I wasn't sure what else to try.

At the end of the day, my IC works but the battery option I tried failed. I'm tempted to replace the battery itself - I suppose it is possible I got a dud.

Another option is to get a 3.6v cordless phone rechargeable battery pack and solder wires to the motherboard so the pack can stay velcroed out of harms way. These batteries usually don't leak and can last quite a long time.
Do you have any more information on this particular hack? If I get the itch again, I might go for it. But if you solder the wires to where the original battery stand goes, then I'll still be out of luck I'm pretty sure.
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Zippy Zapp
CA, USA

by Zippy Zapp posted Thu Feb 02, 2017 11:58 am

That's a bummer. The first thing I would do is indeed test the battery.

The second thing I would do is use a multi-meter to trace the Plus and Minus spots on the motherboard to where they connect at the component side. Sorry if this is a dummy version but I don't know your level of expertise with electronics so I am being simple simon here. trace the copper trace from plus side first to where it connects on the other end and see if there is continuity there. If there isn't then you have a break, like you said. You could solder a jumper wire to connect the two locations and that should be that.

I couldn't tell from the pictures, but it didn't look like there was too much damage from the old battery so I am surprised it doesn't work.

As to the cordless battery pack, you can usually find them at Radio Shack or Wall-mart or Target. Find one that is rated 3.6v, and either NiMh or NiCad. Don't use Li-ion as they have a different charge requirement. There are some that have a connector with two wires going to the pack. You then just lop off the connector and tin and solder the wires to the plus and minus of the battery terminal on the Motherboard. You could also solder on longer wires or even better uses some wire connectors so that you can make the pack removable.

I have read that some Amiga's don't like the CR2032 option as after the diode the voltage drops to below 3V and depending on the RTC chip could be insufficient to save the time. This is for sure more rare so you may need to check all the connections first. Check to make sure you are also getting voltage out of the pins on the battery holder too to rule out a broken circuit board battery holder.

Hope it helps. If I was closer to your location would love to be available in person, even though I am mostly a hack. ;)
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intric8
Seattle, WA, USA

by intric8 posted Thu Feb 02, 2017 12:08 pm

Sorry if this is a dummy version but I don't know your level of expertise with electronics so I am being simple simon here.
In terms of using a multimeter, I've never used one. But I'm always up for learning something new.

I couldn't tell from the pictures, but it didn't look like there was too much damage from the old battery so I am surprised it doesn't work.
Me too! :(

All your ideas are interesting. I should get the multimeter and learn how to use it. If my dead board isn't dead due to the battery, it's probably the Agnus or CPU. Be nice to figure that out and get some use out of it, if that's possible.

Speaking of being in my location, there is going to be a small meetup in June with folks who frequent the Centronian BBS, among others, at the Living Computer Museum in Seattle. Alternatively, I hope to also attend the Portland Retro Gaming Expo in October again. We went last year and it was amazing. Taking some gear down to fiddle and compare would be cool at some point. Be fun to meet you et al at one of these events some day.
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motrucker
Maryland, USA

by motrucker posted Thu Feb 02, 2017 6:29 pm

I'm going to have start hunting down a new battery soon. My OEM type isn't leaking, but it's about 5 years old now.
My battery is no longer on the motherboard however. The previous own ran wires to a new battery, and glued it into a small lucite "bottle" (case?) so it can't leak onto the board. I may go to a newer coin type battery - not sure yet.
I'll take a photo the next time the case is off.
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intric8
Seattle, WA, USA

by intric8 posted Thu Feb 02, 2017 6:49 pm

@motrucker, which rev board do you have, out of curiosity's sake?
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Zippy Zapp
CA, USA

by Zippy Zapp posted Fri Feb 03, 2017 10:01 pm

Yes a multi-meter will be helpful and not too hard to learn for basic testing. For the simple tests for battery and continuity any cheapo meter should work from walmart or Radio shack. Of course if you pay a little more you get a little more.

One thing I forgot to mention though is that sometimes you need to reset the RTC before it will save. If my memory is correct you do that by issuing the command in the CLI: setclock reset.

Then set the date and time using the DATE command in the CLI:
(IE: DATE 3-feb-17 22:00:00 would set the clock to 2/03/2017 10:00 PM).

Next use "setclock save" and endcli and power down and see if it comes back up when you power it back on.

Of course you need to have "setclock load" in your Startup-Sequence or type "setclock load" in the CLI after boot.
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intric8
Seattle, WA, USA

by intric8 posted Fri Feb 03, 2017 10:31 pm

I'll try that again ZZ, but I did do a reset at one stage in the CLI but not all of the commands in the set order you laid out. I have a sinking feeling when I did do the reset the other attempts I've made should have stuck along the way.

Either way I think you're right - I should get a multimeter and learn to use it. All of this hardware is getting to an age where we all need to know how to diagnose issues. And I'm the first to raise my hand in admitting ignorance in this area.

I'll follow your advice and find some gear.
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intric8
Seattle, WA, USA

by intric8 posted Sun Feb 05, 2017 8:24 am

Check out this crazy setup (for only $8). Works with 500, 2000, 3000 and 4000.
Attachments
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Shot97
Detroit, MI, USA

by Shot97 posted Sun Feb 05, 2017 9:00 am

I've seen double A's before in old PCs. I keep meaning to put a new one in but I guess I'm fine with just having gotten rid of the battery all together.

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