The most common version of the ACT Sirius 1 and Victor 9000 was with two floppy drives fitted. The drives are full height 5¼" Tandon drives. These drives are the same as IBM drives with the same dimensions but with the electronics removed. They are in fact very basic drives as all the necessary electronics are on the Disk Controller Board. They came in either single sided or double sided design. In the single sided drive the active head is at the top of the head carrage.

There are only two major PCB's in the floppy system, the first being the Main Board. This is the same in all versions including HD versions. The only other board is the Disk Controller Board connected to the Main Board by a 60 way ribbon cable. The floppy drives connect using several small plugs that attach to the Disk Controller.

Disk Controller Board

This is a standard Disk Controller that is used in both Single and Double sided configurations. There are many floppy drive plugs needing connection to the controller. All plugs have a number printed on the 'down' face of the plug but not all controller boards have corresponding signage printed on them. The image below shows a full row of plugs for a single sided floppy machine. Regardless of what type of floppy drive fitted it is important that the numbers on the plugs are fitted in the correct order. Some floppys appear to have a plug or two missing but whatever plugs ensure they are fitted onto their correct set of pins.

You will note from the above image that two pins are not used these are (counted from right to left) pin 5 beside plug 12 and the last pin beside 12. You will notice a pattern in that the plugs are a mirror of themselves from the center out.

Some Disk Controller Boards have the plug numbers printed on them some do not. On the ones that do you will notice that the plug numbers are preceded by a letter such as A9 this denotes that this is for plug 9 of the first or A drive. A plug for the B drive is denoted as B22.

Another very important set of connections are the plugs for the disk drive heads. On a single sided drive there is only one plug per drive with the number 0 printed on, if double sided drives are fitted there will be two plugs fitted each with a number 0 and number 1. Be very careful should you need to remove these plugs as once damaged they ar very difficult to repair. Always firmly grip the plug to remove it and NOT pull the thin wires they will break. The image below shows both configurations single sided on the left and double sided on the right.

    

There are a few unusual Disk Controller boards that have some of the drive plugs fitted to the Disk Controller and the rest are fitted to a harness. These are unusual and at this time it is not known if a standard Disk Controller Board can be substituted in the event of a failure. When more information is known it will be posted here.

Here is a full setup of a floppy machine with the power supply removed for clarity.