26 Mar
2018
26 Mar
'18
6:59 p.m.
Hi Andrea,
Thanks for your suggestions.
Checking the amplified output from the r/w heads is one of the first
things I did. The voltages are within normal range, but only after I
push the head a bit further into the pack.
Although, I did not set the jumper to try the other head (I suppose I
was always looking at head 0), so I've just tried this now. There does
indeed appear to be servo burst data coming from both heads once I've
manually loaded them fully. So I am not sure if this is the problem. I'm
really hoping that the pack is not bad since I paid for a tested pack.
I also checked the sector transducer output last night. The individual
waves (i.e. from trough to peak) seem to be twice as fast, but the
timings between two peaks is correct.
The survo busts are correctly aligned with the sector pulses.
So, from what I can see, the drive should spin up correctly, but for
some reason it goes into fault mode. I am right in thinking that upon
load, the heads should continue moving forward until the first track is
found, right? I should not have to perform a seek manually from the PDP?
If this is not the case, perhaps there is something else wrong.
Thanks again for your input,
Aaron.
shadoooo via cctalk writes:
Hello,
I'm not an absolute expert, but I successfully fixed a couple of RL02 in
the past.
Adjustment to the head is only useful for azimuth, I think. The radial
position will be adjusted continuously using the servo tracks, so there's
no absolute position adjustment at all.
If the drive fails during spinup, I would check at least the following:
- the presence of spindle sector signal after digital conversion of pulses
from analog signal coming from the pickup.
- having disabled the servo linear motor (there's some jumper to setup,
check the maintenance manual), perform the motor spinup, then load slowly
the heads on the disk by hand, until you find the servo tracks.
- with an oscilloscope check the presence of analog signal of the servo
tracks on both heads, and it's digital counterpart after amplification and
threshold detection (expected level values in the manual). If you see
something strange, e.g missing or too short pulses, try to adjust the gain
with the trimmer on the head board
- enable again the servo, then load again
My 2 cents.
Andrea
--
Aaron Jackson
PhD Student, Computer Vision Laboratory, Uni of Nottingham
http://aaronsplace.co.uk