PC FDD in CPC6x - drive B: as A:

[MCbx]

I'm going to build an external 3.5" FDD for my Schneider CPC6128. It has Centronics connector, so I'm going to add a Centronics plug to ribbon cable as shown in http://www.ulrich-cordes.de/cpc/english/disk.htm, shorting pins 1 and 2 (using PC numbering) or 33 and 34 (in CPC numbering). The next thing will be a disk side switch, connecting pins 3 and 4 (or 31 and 32).

My question is about pins 11 and 12 (CPC numbering), they sould be shorted to turn drive B: to A:. When should I short it to make it work? After the 3.5" drive gets power or after CPC is turned on?

Another question is about powering the drive - If I connect the drive to 12V source from CPC color monitor (5V from 7805 with some heatsink) will it be OK for power supply in CPC monitor?

Sorry for my English.
MCbx

[arnoldemu]

My question is about pins 11 and 12 (CPC numbering), they sould be shorted to turn drive B: to A:. When should I short it to make it work? After the 3.5" drive gets power or after CPC is turned on?

Another question is about powering the drive - If I connect the drive to 12V source from CPC color monitor (5V from 7805 with some heatsink) will it be OK for power supply in CPC monitor?

Sorry for my English.
MCbx

Power: From my experience the CPC colour monitor doesn't have a lot of power, so you may not be lucky to take extra power from it. I have always used an external power supply for my drives.

Drive B to Drive A: Are you adding a switch so you can choose which drive is A and which is B? I don't think you need to short the pins to do this, but wire so that the states swap. (I can't remember the name for the switch but it has 4 connections on bottom, and it switches two circuits at the same time.
The "ABBA" switch is what I know it as.

[MCbx]

According to this: http://cpcwiki.eu/index.php/Guide_on_how_to_connect_a_3.5%22_drive_to_a_CPC6128/664
the pins 11 and 12 should be connected to switch the drive, and it should be done "after powerup". But after drive's powerup or CPC powerup?