Amiga battery replacement

[vroom6sri]

Does an A1200 have a clock with battery as standard? If so I guess I really should remove it coz it must be ancient by now and I'll just buy the clock add-on for my Indivision computers accelerator.

[Paul_s]

Originally Posted by vroom6sri

Does an A1200 have a clock with battery as standard? If so I guess I really should remove it coz it must be ancient by now and I'll just buy the clock add-on for my Indivision computers accelerator.

no it doesn't come with a battery onboard.

[vroom6sri]

That's good to know in some ways. At least I don't have to take it apart to remove an old, soon-to-be-leaking battery!

Cheers.

Guess I'll be buying the clock upgrade for the Indiv Comp accelerator when I order one of those funky card reader thingies later in the new year.

[ceaser]

On my A4000 I didn't even bother putting a new battery in, because I don't want to have to take the mainboard out again in 8 years. My A3000 I have to do a battery replace or else just leave that out too, because the battery is old and getting to critical stages. And I have an A500 + that had a bad battery and I replaced it with a new NiCd and either did a bad solder job or the old, slightly leaking battery destroyed the circut. I think leaving them without a battery is better. If you're 100% and you never fail at soldering and love doing it, then replace batteries. And if you put a 3v battery in I highly doubt it's going to do any damage. I've seen that mod. A4000 rev. D motherboards, which were rare, actually had CR2032 batteries I think.

[Paul_s]

Commodore acid Battery plague list;

A501 RAM expansion for A500/+
A500+
A2000 Series (all - A1500 is a rebadged A2000)
A3000/T Series (all - including the AA3000/A3000+/Nyx prototypes)
A4000 (desktop only)

[wanderer]

Thanks Paul_s, after reading about the battery horror stories, I open my A500 but was a bit baffled at first, since I couldn't find one. I guess it's not a problem with an unexpanded A500, A1000, A1200 and CD32.

[Paul_s]

Originally Posted by wanderer

Thanks Paul_s, after reading about the battery horror stories, I open my A500 but was a bit baffled at first, since I couldn't find one. I guess it's not a problem with an unexpanded A500, A1000, A1200 and CD32.

Just those I listed are affected from the C= factory. Every other model do not have them as standard (such as the original 500/1200/CD32 etc).

It's still good practice to check though on all models as certain 3rd party RAM cards had them present too!

On the 4000/CD32/1200 - check the capacitors as the SMD types have a tendancy to leak with them being low-cost types from the factory (if the SMD pads look discoloured or dark i.e. not shiny, then they should be replaced).

[wanderer]

Originally Posted by Paul_s

It's still good practice to check though on all models as certain 3rd party RAM cards had them present too!On the 4000/CD32/1200 - check the capacitors as the SMD types have a tendancy to leak with them being low-cost types from the factory (if the SMD pads look discoloured or dark i.e. not shiny, then they should be replaced).

Thanks for the info, Wow, even on a simple A500 memory expansion card? I've got one installed which seems impossible to pull out.

[Amicol]

Originally Posted by craggus2000

I did use a rechargeable coin battery.... ML2032

Bump:

Sorry an old thread, but a word of warning, I tried this battery after reading this thread. After about a week of use the battery is bulged and ready to explode!

Don't use them in the Amiga 500+

Update: I have measured the voltage going to it when the Amiga is switched on and it's 5.30v. Much too high for this battery I think.
Anyone know how to reduce it before I try another (I have a spare)?

[demolition]

Originally Posted by Amicol

Sorry an old thread, but a word of warning, I tried this battery after reading this thread. After about a week of use the battery is bulged and ready to explode!

Don't use them in the Amiga 500+

Update: I have measured the voltage going to it when the Amiga is switched on and it's 5.30v. Much too high for this battery I think.
Anyone know how to reduce it before I try another (I have a spare)?

That is because they are not meant to be charged like the original batteries. You can disable the charging by putting a diode in series with the battery. Amigakit is using that solution on their battery kit:
http://amigakit.leamancomputing.com/...oducts_id=1093

I put one of those in my 500+ and it works great.

[Amicol]

Originally Posted by demolition

That is because they are not meant to be charged like the original batteries. You can disable the charging by putting a diode in series with the battery. Amigakit is using that solution on their battery kit:
http://amigakit.leamancomputing.com/...oducts_id=1093

I put one of those in my 500+ and it works great.

The ML2032 is a rechargeable battery, but will not take over 3.5v when charging. Since I measured 5.3v going to it from the Amiga, I figured this was the problem.
Can't this rechargeable battery be charged from the motherboard?

[demolition]

True, I missed that it was the rechargable version.
According to this data sheet, the voltage should stay below 3.3V:
http://community.psion.com/cfs-file....2032_2900_.pdf

Putting three regular diodes (like 1N4148) in series with it should drop the voltage down to a safe level, although with 5.3V it might be pushing it. I'd put a 3.3V zener diode across the battery to make sure it doesn't go to 3.4 or 3.5V. You'd also need a shottky diode in the other direction so the battery can supply voltage. So 5 diodes in total should keep it in line..

[Amicol]

@demolition
Thanks for that mate, sounds a bit complicated for me though.
Is there another suitable 3.3v source on the motherboard I could use instead?

[demolition]

Don't think so. The simplest solution would probably be to put a CR2032 in there with a single diode to disable charging, like the Amigakit adapter. It will run the clock for many years without charging (maybe 10 years?).

[Amicol]

Originally Posted by demolition

Don't think so. The simplest solution would probably be to put a CR2032 in there with a single diode to disable charging, like the Amigakit adapter. It will run the clock for many years without charging (maybe 10 years?).

I think you're right mate, I'll order one from Amigakit

[Brannigan]

Any particular Schottky diod being recommended for the CR2032 mod? I have some BAT85. Are they ok for the task?

[demolition]

BAT85 should work fine.

[jimbob]

Originally Posted by Amicol

Bump:

Sorry an old thread, but a word of warning, I tried this battery after reading this thread. After about a week of use the battery is bulged and ready to explode!

Don't use them in the Amiga 500+

Update: I have measured the voltage going to it when the Amiga is switched on and it's 5.30v. Much too high for this battery I think.
Anyone know how to reduce it before I try another (I have a spare)?

Oh crap, thanks for the warning. I've used a few of these and will need to get them sorted. Mental note, always read the data sheet. Theres a big graph of the charging voltage with "prohibited area" in big writing, d'oh.

[Photon]

Originally Posted by craggus2000

Hi,

Quick question: is the lithium battery (CR2032) + diode the preferred type of battery replacement method in the A500plus?

Many thanks

You should add a diode and a resistor, like this. I wrote this article to make Amiga users not put rechargable batteries back in their Amigas and answer the questions about diode and resistor etc. If you guys have suggestions for improvement, please feedback!

[Jope]

Let's see when the first diode failure / exploded coin cell happens. Lots of guys have been fitting these with just the diode. :-)