RD53 failure modes
carlos_murillo at ieee.org
Sun Mar 8 16:12:50 CDT 2020
On Mon, Feb 10, 2020 at 6:16 PM Fred Cisin via cctalk <cctalk at classiccmp.org>
> On Fri, 7 Feb 2020, Carlos E Murillo-Sanchez via cctalk wrote:
> > system originally came with an RD53 that has sat elsewhere for 25
> years. It
> > passed a read test in 2005. So I tried to see if I could read it and
> > image it now, but no go. The disk spins up, initiates a seek (the arm is
> > stuck in a gooey stop pad; I've read that this is a common failure
> > for Micropolis 1325's; I opened it and saw the arm move) but then the
> > returns violently (clacking) to the rest position; it does this a number
> > times (two to four, usually) and then it spins down. Applied voltages
> > currents remain ok as this happens.
> If nobody speaks up who actually know anything about them, . . .
> Q: Is the return to the reset position more violent than the usual return?
> If it is not different, then consider the possibility of something not
> related to positioner, such as: seek to track, try to READ, FAIL, reset,
> REPEAT. In which case, it could be anything that caused the read to fail,
> such as head problems, failing to find the servo data, . . .
Sorry for not replying earlier, your message made it to the spam folder.
The return is more violent than the usual return. I put a piece of paper
between the arm stop and the arm, and this did not modify the behavior. I
am now inclined to think that it is failing to find the servo data.
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