Date   : Tue, 18 Mar 2008 08:54:12 -0500
From   : jules.richardson99@... (Jules Richardson)
Subject: Disc drive power

Ian Wolstenholme wrote:
> Thanks to everyone who replied.  It sounds like this might be a dead
> duck.  I was trying to find a simple solution to the question I get asked
> a lot: how people can convert their old 5.25" discs to 3.5".  I already
> have some 3.5" drives for sale and thought I could use these for people
> to connect up to their existing 5.25" drive by crimping an extra connector
> on to the ribbon cable, but that doesn't deal with how the new drive
> would be powered.

There's no 'smarts' on a standard Shugart-a-like floppy drive - it needs 
something to tell it when to step the heads and read/write data. So you still 
need some sort of microprocessor solution to copy between two drives (although 
doubtless something could be bodged with a handful of LS-TTL chips :-)

> I know that the old drive could be dismantled and then the power lead
> re-wired to accommodate both drives but I was hoping for a simple
> plug-in-and-go solution for the non-technical people.

It still needs at least +5V from *somewhere* for the drive's (rather limited) 
logic and analogue circuitry, even if you happened to find some drives that 
didn't need +12V.

I think the closest to "plug in and go" is:

1) Use a real BBC micro*,

2) Use a PC with both 3.5" and 5.25" drives - if you can find one that'll 
write FM data!

* Hmm, you're not forgetting that the BBC has +12V available on the AUX power 
connector are you? I have/had several beebs over the years with external 
drives that were powered from this connector. I'm not sure you could quite get 
away with two 5.25" drives powered this way (the load might be too high), but 
3.5" + 5.25" might be OK.

cheers

Jules