What is -5VDC on Amiga power supplies for?

[redrumloa]

Sigh...

Many Amiga power supplies (2000, 3000, 4000 etc)have a -5VDC. What is this used for?

[Tension]

And what is the mystery pin for?

[JimS]

near as i can tell, it only goes to the Zorro slots, the pc slots and the video slots. i remember some of those old isa cards needed it for certain chips.

[rkauer]

redrumloa wrote:
Sigh...

Many Amiga power supplies (2000, 3000, 4000 etc)have a -5VDC. What is this used for?

 Supply the voltage for bridgeboards and ISA boards who require them, like Time Base Correctors (TBC) and some Ethernet NIC.

[Illuwatar]

And internally too - by the analog section (audio filter OP-amp).

[Lockon_15]

Serial port driver MC1488/MC1489

[darksun9210]

its so your machine can supply power back to the mains if you apply sudden loading, like switching a kettle on....









 :lol:

[keropi]

the only ISA card that I know of that requires -5v is the 8bit ROLAND LAPC-I ...

[Tension]

In order to stop the effects of Heavy Electricity, the -5v line is used to extract `sodomised electrons` from the PCB of the Amiga.

[djbase]

Illuwatar wrote:
And internally too - by the analog section (audio filter OP-amp).

Thats -12V, desktop amigas (A500,A600,A1200,CD32) don't have -5V.

[Framiga]

A4000s jave it

A4000

U198

7905

TO-220

[redrumloa]

So, nothing internally uses -5VDC?

[Framiga]

AFAIK internally, nothing.

[hardlink]

redrumloa wrote:
So, nothing internally uses -5VDC?

To be clear, I suppose you have to put the 'native Amiga hardware' condition on that. I use BridgeBoards & ISA cards that may require the -5VDC, but those are expansions (though internal).

[redrumloa]

hardlink wrote:
To be clear, I suppose you have to put the 'native Amiga hardware' condition on that. I use BridgeBoards & ISA cards that may require the -5VDC, but those are expansions (though internal).

Yes, without ISA cards I mean. The Amiga shoot boot without -5VDC present, which appears to be the case.