18 May
2010
18 May
'10
1:28 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Tony Duell
Sent: 18 May 2010 19:44
To: cctalk at classiccmp.org
Subject: Re: RD53 Restoration
As we all well know, funding the fault is often a lot harder than
repairing it...
Do the schematics for the RD53 exist on the web? I've not looked. Or am
I
going to have to take one of mine apart and work out how it should
work..
This is going to sound silly, but do you have one of those DEC mounting
skids fitted? I had problems with an RD53 that wouldn't work if the
skid
was on. Turns out some component leads were shorting to the ground
plate
on the skid. A piee of cardboard cured that :-)
Could that be because the new boards are a different rev and perhaps expect
something different? The other thing I have just remembered is that the new
boards are missing the graphite pad under the spindle, but then again I have
run the original boards successfully with the bottom board lifted up so I
can probe voltages, so not sure that would have any effect.
I have yet to find the time to put back the old boards, I get home late and
have to be up early. But I will swap them again as soon as I can.
Regards
Rob
> > Yes "blipping" the coil with
a 9V battery moves the heads. When
the
> drive
> > was powered on I also measured the voltage by attaching a probe
to
> each end
> > of the coil cable, in that case I measured about 1.3V only. So I
am
guessing
Indeed, if only I knew what it was! the coil is OK. Next step is to swap the boards
back again.
And then fix the real fault :-) The problem for me is how to diagnose this. I am
pretty sure the
motor is up
to speed. However one thing that does seem
slightly odd is that it
starts to
spin the disk down quite soon after power up.
Previously with the old
Is it possible it doesn;t think the motor is properly up to speed? I
wonder how it senses that? if it thinks there's a problem with the
motor,
it will spin down fairly quickly.