8 Oct
2016
8 Oct
'16
6:18 a.m.
I have an RD53 disk drive. When I plugged it in the other day something blew
up, smoke etc. I found that it was a tantalum capacitor on the motor control
board that had gone. I suppose I am wondering if just replacing it is a good
idea, could the failure be a symptom of another problem, could it have
damaged something else? I realise that without a schematic it may be
difficult to comment, but I suppose it is more a question about what can
cause these caps to fail?
If anyone has a schematic, or a drive they can examine, it is C1 on the
motor control board, quite close to the molex socket for power.
Regards
Rob
8 Oct
8 Oct
7:18 a.m.
On 08/10/2016 11:18, "Rob Jarratt" <robert.jarratt at ntlworld.com>
wrote:
I have an RD53 disk drive. When I plugged it in the
other day something blew
up, smoke etc. I found that it was a tantalum capacitor on the motor control
board that had gone. I suppose I am wondering if just replacing it is a good
idea, could the failure be a symptom of another problem, could it have
damaged something else? I realise that without a schematic it may be
difficult to comment, but I suppose it is more a question about what can
cause these caps to fail?
I plugged in the power supply from a NASCOM2 the other week and one of the
tants exploded but the supply still worked so I just replaced it and all was
well, similarly with the floppy drive in an IBM5150 a few years ago. I was
told they can go short-circuit when they fail so explode in a similar manner
to fitting one in reverse polarity. (*innocent whistle*).
--
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?
12:39 p.m.
On 10/08/2016 05:18 AM, Rob Jarratt wrote:
I have an RD53 disk drive. When I plugged it in the
other day something blew
up, smoke etc. I found that it was a tantalum capacitor on the motor control
board that had gone. I suppose I am wondering if just replacing it is a good
idea, could the failure be a symptom of another problem, could it have
damaged something else? I realise that without a schematic it may be
difficult to comment, but I suppose it is more a question about what can
cause these caps to fail?
A WELL-KNOWN problem with Tantalum caps is that if run in
equipment for some time, then put on the shelf for some
years, then powered up again, the caps will fail, often
spectacularly. Sometimes, in things like memory boards, you
will have to replace many caps. Likely, just the cap is bad,
if it is on an externally-supplied power rail. Supposedly,
if you were to ramp up the supply voltage slowly, it would
allow the cap's dielectric to reform gracefully.
Jon
2:07 p.m.
A WELL-KNOWN problem with Tantalum caps is that if run
in equipment for
some time, then put on the shelf for some years, then powered up again,
the caps will fail, often spectacularly. Sometimes, in things like memory
boards, you will have to replace many caps. Likely, just the cap is bad,
if it is
on an externally-supplied power rail. Supposedly, if
you were to ramp up
the
supply voltage slowly, it would allow the cap's
dielectric to reform
gracefully.
2:25 p.m.
On 08/10/2016 19:07, "Rob Jarratt" <robert.jarratt at ntlworld.com>
wrote:
I went ahead and replaced it. The drive spins up now, but sadly the drive
doesn't actually work, after spinning up and making a few clunking noises,
it spins down again. I suspect it is trying, and failing, to find track 0.
You're aware of the infamous stiction problem with RD53s? The rubber buffer
that the head rests against when it's parked turns to goo and the head
sticks to it and can't move. Top off, unstick head and top back on again.
--
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?
A WELL-KNOWN
problem with Tantalum caps is that if run in equipment for
some time, then put on the shelf for some years, then powered up again,
the caps will fail, often spectacularly. Sometimes, in things like memory
boards, you will have to replace many caps. Likely, just the cap is bad,
if it is
on an externally-supplied power rail.
Supposedly, if you were to ramp up
the
supply voltage slowly, it would allow the
cap's dielectric to reform
gracefully.
2:27 p.m.
On 10/8/16 11:07 AM, Rob Jarratt wrote:
I went ahead and replaced it. The drive spins up now,
but sadly the drive
doesn't actually work, after spinning up and making a few clunking noises,
it spins down again. I suspect it is trying, and failing, to find track 0.
EXTREMELY common problem with Micropolis 13xx series drives. If you're lucky
the head is just stuck to the parking bumper. Unlucky if you ever want to put
the drive back in use without a clean room.
2:30 p.m.
And stuck Maxtor coaxial spindle motors (RK54) are no joy either.
On 10/8/16 11:27 AM, Al Kossow wrote:
On 10/8/16 11:07 AM, Rob Jarratt wrote:
I went ahead and replaced it. The drive spins up
now, but sadly the drive
doesn't actually work, after spinning up and making a few clunking noises,
it spins down again. I suspect it is trying, and failing, to find track 0.
EXTREMELY common problem with Micropolis 13xx series drives. If you're lucky
the head is just stuck to the parking bumper. Unlucky if you ever want to put
the drive back in use without a clean room.
2878
days inactive
2878
days old
6 comments
4 participants
participants (4)
-
aek＠bitsavers.org -
elson＠pico-systems.com -
robert.jarratt＠ntlworld.com -
witchy＠binarydinosaurs.co.uk