RL02 Tracking

[Christian Corti]

On Mon, 21 Dec 2020, Aaron Jackson wrote:
> The status currently is that the heads will load, and the ready lamp
> flashes as the heads wobble back and forth very slightly, trying to lock
> onto the outer servo guard band. Probing TP2 of the read/write module, I
> can see the S1 servo burst flash (roughly in time with the ready
> lamp). If I disconnect power to the servo motor, I can manually move the
> head onto the outer guard band (less than a mm away) and monitoring the
> position signal (TP15 on the drive logic module) shows this to be close
> to 0. So, I'm very confused.

I've had almost the identical problem with a RL02 drive from a friend. It 
would start and load the heads, but the ready light would flicker or not 
even come on. After a measuring session I discovered that if I manually 
select the other head, everything would be fine. And if I disabled the 
servo motor I could manually lock onto the track on side 0, but then side 
1 was out of alignment. So the alignment between the two heads was wrong 
and I had then aligned one of the heads so that the two would lock onto 
their corresponding track. The drive works fine since then.

Christian