working magnetic drum stores?

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Thu Apr 1 16:44:32 2004

> Tony> You hope... If the power fails and your NiCd pack isn't any
> Tony> good, then the heads will land on the platter with nasty
> Tony> results...
>
> NiCd? You must be thinking of the big capacitors (not batteries) that
> do the emergency head retract in the event of powerfail.

No, I am thinking of the 4-cell NiCd pack (look to be 1/2AA size cells --
it's certainly the same pack is in some cordless phones) on top of the
PSU chassis (rear left) in an RK05. It's connected to the positioner coil
via one of the relay contacts and the home microswitch to cause an
emergency retract if the relay drops out i.e. if the mains fails.

It's certainly a battery and not a capacitor. I do know the difference,
I've read the RK05 printset, and in fact I've replaced the batteries in
all my RK05s (and, indeed my RK07s, which have an 8-cell pack under the
chassis).

>
> Tony> Anyway, the 'ting' when the heads load on an RK05 is claimed to
> Tony> be the heads bouncing off the platter, so they may well touch
> Tony> for an instant.
>
> I rather doubt that. The sound is no different from the "ting" sound
> you hear when the head actuator seeks.

I can certainly tell the difference. There is a very metallic ring when
the heads load, but not when they seek.

-tony
Received on Thu Apr 01 2004 - 16:44:32 BST