So I have some questions for anyone on the list who
may have changed their
I have replaced RK05 heads, but I had the proper DEC spare part (:-))
complete with the leaf spring/mounting strip.
1. How hard is it to mount the head in the tongue? Looks like just 2
I think that's right. I assuem the screws go into threaded bushes in the
ceramic disk, so you ened ot be very careful when tightening them. I also
wonder if there's enouygh free play in thge mounting holes to mean the
head azimuth (angle between the gap and the track, basically) will not
necessarily be corrrect. Setting that could be 'interesting'.
2. How hard is it to remove/replace the tongue
assembly? Looks like it
mounts with a couple of allen screws.
There are 2 allen setscrews per head. One clamps the head assembly, the
other is used to push the head towards the spindle,. When fitting a new
head, you start wit hthe second oen beacked off, then slide in the head.
Put in the alignment disk, seek to the right cylinder and carefully screw
i nthe adjusting screw until the lobes on the 'scope screen are the same
size. If you go too far you ahve to unload the heads, push the head back
by hand, then try again. Actually, it's not that hard.
I recoment gettting the RK05 maintenance manual, I guess it's on
bitsavers. There is a warning that these screws go into a fairly soft
alloy casting, and it's possible to strip the threads. There is an
official torque setting, but I guess very few peoplehave a torque wrench
that goes down that low
On other thing. The leaf springs force the heads onto the disk, and thus
towards each other. Wehn fitting or removign a head, make sure they don't
suddenly srpign together, or you may damage the face of the enw head.
It's a good idea to fit the shippling lock o nthe positioner to hold the
carriage back when your are ahdnlign the heads. It's one less thing to
3. How hard is it to align the heads? I don't
have a CE pack so I'll just
have to use a pack that works okay on the other drive.
I have the EE pack... With that it's quite easy. I susepct you could
align for peak output or something like thwt. Maybe putt in the
known-good pack, then scre in the adjusting screw whilecounting the turns
and noticing when the amplitude starts to rise and when the signal
vanishes again. Then start again,m note where the amplitde starts to rise
and screw in half as many turns as it took for the amplitude ot flal off.
That should get the head over the middle of the track.
I don't know how weay it would be, but if possible, start witha
bulk-erased pack (rememebr, no servo information on these disks) and
format one cylinder (knowing which oen it is!). Then set up on that. This
will avoid gettign the heads aligned on the wrong cylinder.