12 May
2015
12 May
'15
1:31 p.m.
I can really sympathise with you on the PSU front. I tried to repair one of
these, but it was designed in such a way that it was really hard to get at
the caps to remove them for testing. My problem was that even when I did
get to the big Sprague one I couldn't desolder it, presumably there was a
large track/plane taking all the heat away. In the end I gave that PSU away
(along with another working one) to someone who is much better than me.
Although I don't know if he has fixed it yet.
Regards
Rob
On 12 May 2015 at 13:33, Holm Tiffe <holm at freibergnet.de> wrote:
Johnny Billquist wrote:
The exerciser showed some correctable soft errors, wich is pretty much
normal I think. Reformating the drive should simply "freshen up" the data
tracks but erase should do the same in this regard.
Since the distks aren't containing anything interresting, it would be the
right time now to do a reformat.
I think the head assembly has an voice coil engine anyways, so servo tracks
are needed to do the positioning. It is clear that they aren't affected
from
a reformat...
I've changed some Nippon Chemicon electrolytics from the PSU now. All
330?F 25V Caps are bad, an 1000?F 25V too, where other Caps from the same
company are still ok. I've changed the 330? Caps against some good Rubycons
470? 25V from which I have "masses".
The construktor of that H7874 Supply is an dump asshole, no one should ever
construct switching PSU's in a way that it makes it impossible to desolder
broken electrolytic Caps! One module with 2 x 330?F Caps is build this way!
I had to pull of that bad caps, ..brown residues from the electrolyte below
them on the pcb. Cleaned the PCB with alcohol and soldered the new caps
from
above, briged them with an 1206 X7R each.
Will test the PSU now...
[..]
Machine is working now as expected. Currently it is "erasing" the Disk0..
53 Minutes...
Regards,
Holm
--
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On 2015-05-12 11:55, Holm Tiffe wrote:
procedure.
Ok, the disk passed the tests with ok.
Excellent.
I've tried to boot something from DIA0 DIA1
and DIA2..nosurchfile so the
disks seems to be empty.
Oh Well...
>Now I think about a reformat of the drives, but there is no such >There is an erase program that should rewrite
eachs sector with several
>patterns. I'll think that it will do the job.
>Does an format programm exists "in the field" or is something like
thisi
proprietary to DEC?
Why would you want to reformat the drives?
That said, I would expect such a utility to exist in the firmware of the
drive.
But normally, since these drives remap bad sectors automatically, you
should normally just go on using them, and everything is ok.
Johnny