Firing up the pdt11

Chris Zach cz at
Mon Oct 12 06:59:17 CDT 2020

> When you swap the cables (and keep the drives in place), do you mean
> that you swapped the data connection **and** the power supply cable(s)?

There are six wire bundles and connectors that hook an RX01 floppy drive 
sub-module to the RX01 read/write controller board (or the PDT11 
controller board)

One is for the solenoid that lowers the pad onto the disk to allow 

One is for the sensor to detect track 1 (LED and detector)

One is for the sensor to detect sector pulse

One is for the servo motor that moves the head in and out

One is for the read/write head

One is for the 110v power to the drive motor itself that spins the belt 
and the disk via the center spindle.

I did not move the 110v power wire because that is from a common harness 
between the drives and it's pretty obvious the disk is spinning. :-) The 
other five were switched between controller channel 0 and 1 (PD0: and PD1:)

At this point I think I'm onto the sector pulse LED not working due to 
5v being applied to it. Will be working on that more this morning with a 
better/more precise power supply.


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