Amiga.org

Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: redrumloa on December 08, 2008, 01:52:05 AM

Title: What is -5VDC on Amiga power supplies for?
Post by: redrumloa on December 08, 2008, 01:52:05 AM
Sigh...

Many Amiga power supplies (2000, 3000, 4000 etc)have a -5VDC. What is this used for?
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: Tension on December 08, 2008, 02:58:37 AM
And what is the mystery pin for?
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: JimS on December 08, 2008, 03:21:19 AM
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.
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: rkauer on December 08, 2008, 03:26:27 AM
Quote

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.
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: Illuwatar on December 08, 2008, 07:08:47 AM
And internally too - by the analog section (audio filter OP-amp).
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: Lockon_15 on December 08, 2008, 07:13:26 AM
Serial port driver MC1488/MC1489
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: darksun9210 on December 08, 2008, 07:39:52 AM
its so your machine can supply power back to the mains if you apply sudden loading, like switching a kettle on....









 :lol:
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: keropi on December 08, 2008, 08:16:34 AM
the only ISA card that I know of that requires -5v is the 8bit ROLAND LAPC-I ...
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: Tension on December 08, 2008, 05:02:34 PM
In order to stop the effects of Heavy Electricity, the -5v line is used to extract `sodomised electrons` from the PCB of the Amiga.

Title: Re: What is -5VDC on Amiga power supplies for?
Post by: djbase on December 08, 2008, 05:17:21 PM
Quote

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.
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: Framiga on December 08, 2008, 06:18:59 PM
A4000s jave it

A4000

U198

7905

TO-220
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: redrumloa on December 08, 2008, 06:31:47 PM
So, nothing internally uses -5VDC?
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: Framiga on December 08, 2008, 06:40:03 PM
AFAIK internally, nothing.

Title: Re: What is -5VDC on Amiga power supplies for?
Post by: hardlink on December 08, 2008, 06:45:45 PM
Quote

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).
Title: Re: What is -5VDC on Amiga power supplies for?
Post by: redrumloa on December 08, 2008, 09:20:12 PM
Quote

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.