Amiga A4000 Questions

[mfletcher]

Hi,

Just picked up an A4000 from Ebay. It turns out the on board battey has been removed, presumably in case of battery leakage. I assume that I will have to solder a new battery back on to the mobo?

Secondly, from the pictures on the auction, I cant tell if its a dual voltage power supply that it uses. This is a US A4000, when I return to the UK, does it have a switch for UK voltages, or do I have to buy a power converter?

Thanks!

Hardware pr0n will be available as soon as I get it, but in the meantime, here's the pr0n from the auction:

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN:IT&ih=012

[DDNI]

The battery only keeps system time. It is not essential to have it.

I dont have a battery backup in my Amigas. I use a program called FACTS from unsuitable software. It updates system time from a web time server. It does this automatically on system startup.

[alexh]

Tad expensive for an A4k IMHO, more than I've ever paid, but still it was what you wanted.

You will need another power supply for the UK, easy enough to mod a UK ATX PSU.

Might even be worth trying to Ebay the US PSU before you leave the US to pay for a UK ATX PSU and adapter?

[TjLaZer]

Nice system. Those 3.1 disks are not originals btw... But it doesn't matter, its on the CD anyway.

[keropi]

not all ATX psu's will work though! it is hard to get an ATX psu to deliver the reqired 5v signal that amiga needs, I have tried 5-6 of them, and only the older ones are good. All power up, but when it comes to aga stuff (and when u have an expanded amiga) the new ones just lock up or produce gfx errors... also there there is no way to fit a normal size psu inside.. better get an EU A4000 psu from eBay, or post a wanted ad...

[rkauer]

Originally Posted by keropi

not all ATX psu's will work though! it is hard to get an ATX psu to deliver the reqired 5v signal that amiga needs, I have tried 5-6 of them, and only the older ones are good. All power up, but when it comes to aga stuff (and when u have an expanded amiga) the new ones just lock up or produce gfx errors... also there there is no way to fit a normal size psu inside.. better get an EU A4000 psu from eBay, or post a wanted ad...

I really prefer those "baby" AT form factor for those mods.

I've even put one inside an A500 brick with enough space to add floppy drive

[shirsch]

Originally Posted by keropi

not all ATX psu's will work though! it is hard to get an ATX psu to deliver the reqired 5v signal that amiga needs, I have tried 5-6 of them, and only the older ones are good. All power up, but when it comes to aga stuff (and when u have an expanded amiga) the new ones just lock up or produce gfx errors... also there there is no way to fit a normal size psu inside.. better get an EU A4000 psu from eBay, or post a wanted ad...

Odd. Must be beginner's luck. My A4000 PS started getting flaky, so I pulled the guts from a generic ATX supply and fitted it into the A4000 PS case. Took a bit of work, but it will mount on the side with room to spare and runs fine. Jean-Jacques at Amiga Repair Center suggested this approach (thanks again, JJ!)

[Secret Vampire]

I've had good luck with older (mid-late 90s) astec ones in my A4000, whereas cheap generic new ones are near useless, even if they claim to be 500W ones. But the same goes for PCs too, a cheap PSU can lead to instability, it's probably worth reading reviews on toms hardware or similar to find out which PSUs would be a good match for an Amiga, since they do tests of voltage stability, and useful things like protection (A psu failure killing your PC is bad, killing an A4000 is a disaster) some of the higher end models should fit the bill quite well.

[Calgor]

Originally Posted by keropi

not all ATX psu's will work though! it is hard to get an ATX psu to deliver the reqired 5v signal that amiga needs, I have tried 5-6 of them, and only the older ones are good. All power up, but when it comes to aga stuff (and when u have an expanded amiga) the new ones just lock up or produce gfx errors... also there there is no way to fit a normal size psu inside.. better get an EU A4000 psu from eBay, or post a wanted ad...

The newer the PSU, the more likely it is to have a higher minimum load on the 5V and/or 12V rails. Especially a min load on the 12V rails not being met may mean the voltage stability may not be there. It is usually met by PCs with their newer gfx cards, but would probably not be met by many amigas. Also, the newer ATX specifications have removed the mandatory requirement for -5V (which at least the A4000T requires).

The cheaper PSUs generally appear to conform to the older ATX standard, and hence may have lower min loads as well as -5V. I would not think the 500W total "peak" power comes into consideration for the amiga's lowly power requirements.