Amstrad 3in drive spares

Philip Pemberton classiccmp at
Tue Nov 2 16:57:41 CDT 2010

On 02/11/10 20:30, Tony Duell wrote:
> Is there soemthing special about the screw? Why do you need to take it
> from another drirve?

It's a rather small screw. 5mm long, M2.5 or possibly Imperial. 
Naturally the Amstrad service manual doesn't say a damn thing about what 
it is or isn't.

Path of least resistance basically. The 231 is the nicer of the two 
drives, and the one I'd most like to see working: it can handle both 
"flippy" and "true" double-sided 3in discs, the 720K Amstrad discs, and 
the previous-generation 180K SS discs. The 153 can only handle 
single-sided discs, or "flippy" double-sided ones. 180K a side if memory 

> The schematic I have to hand shows SW1 as switching bwtween drive select
> 0 (pin 4 of the connecotr) and drive sleect 1 (pin 6 of the connector.
> The common connection goes to the D-SELCT/ input of the main ASIC.

That's what I got too (from tracing the tracks from the switch to the 
ASIC and the IDC connector)

 > There
> is indeed a jumper to connect up Drive Select 0 if the switch isn't fitted.

JP1, next to the data connector. Short it and the drive is forced to DS0.

> Alas the manual doesn't show PCB layouts, just a schematic  So I have no
> idea if there's an exta non-connected pin on the switch.


Ah well, I can live with it being permanently jumpered for drive select 
0 (drive A or whatever Amstrad called it).

classiccmp at

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