View Full Version : Replacing batteries on A500 Plus and A4000 motherboard

21st October 2009, 13:36
I removed the original Varta NiCad batteries from both my A4000 and A500 Plus quite some time ago because they started to fur up a bit, and have been running both without a battery backed up clock ever since.

However I would like to replace the batteries in both systems with a coin battery holder. I know I need to use a diode with this but can anyone tell me what diode I need to use and if anyone has any they could send me?

A little diagram or pic would also be great as I have next to no electronics experience other than making up cables and soldering wires onto connectors.

I just successfully made an ST to Scart cable last week and that works perfectly. I found it quite fiddly soldering the 11 wires onto the ST connector but got there in the end. Great to finally be running an STE through scart to see what its "real" image looks like rather than via RT lead. Next cable to make is an ST to Amiga monitor one.

21st October 2009, 13:40
harridon, let me check later and i believe i may still have 1 battery kit left (holder, battery and diode) you can have for the cost of postage. At the least i'm positive i have some diodes i can send you.


21st October 2009, 13:43
That's great. Thank you. :)

21st October 2009, 13:46
I searched EAB for "battery diode" and you get lots of hits, there'll be some good info somewhere in those results. Top hit includes a mention of the specific point I was thinking of though - do you need a germanium diode?

Germanium has a lower voltage drop than silicon, it might be better. Zetro or Merlin should be jumping in here soon though, I would have thought, and they're more likely to have actually done this before (I haven't yet).

21st October 2009, 14:41

Have you looked at this thread? viewtopic.php?f=88&t=3555 (http://www.amibay.com/viewtopic.php?f=88&t=3555)

Or on this website http://amiga.serveftp.net/battery.html

If SS can't find enough clips, diodes and batteries let me know. I've got some going spare that I bought before I went with the rechargable ones from CPC.

Dave G 8)

21st October 2009, 17:42
Prefer germanium diodes since they have a lesser voltage drop of 0.3V instead the 0.7V of silicon units.

The 1N60 or other equivalent is preferred over other (more expensive) types. Not that a germanium diode can be expensive (don't pay more than 0.5 for it!).

21st October 2009, 17:51
Is there an easy way to identify diodes similar to how resistors are identified?

21st October 2009, 18:39
Does this help? DIODE MARKINGS (http://www.tpub.com/content/neets/14179/css/14179_56.htm)

21st October 2009, 19:02
@Harrison, unfortunately i've got no battery holders or batteries left but i do have 8 diodes. If you want them i'll send them to you free of charge. i'll pm you


P.S. i followed the information in this article (http://aminet.net/package/docs/hard/LithBatt) from Aminet which shows you a small diagram on how to install them.

22nd October 2009, 00:17
Great. Thanks everyone. Mike is sending me some diodes, and I can get some coin battery holders from some dead motherboards I have, so hopefully I should be sorted. ;)