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From: mikey@trsvax.UUCP
Newsgroups: net.audio
Subject: Re: Query: Stylus Replacement Timer - (nf)
Message-ID: <55100043@trsvax.UUCP>
Date: Wed, 9-May-84 10:18:00 EDT
Article-I.D.: trsvax.55100043
Posted: Wed May  9 10:18:00 1984
Date-Received: Fri, 18-May-84 00:31:05 EDT
References: <223@cubsvax.UUCP>
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Nf-ID: #R:cubsvax:-22300:trsvax:55100043:000:1118
Nf-From: trsvax!mikey    May  9 09:18:00 1984

#R:cubsvax:-22300:trsvax:55100043:000:1118
trsvax!mikey    May  9 09:18:00 1984



BSR used to put such things on their 710 and 810 QX series turntables.
What they are is a small glass tube filled with mercury.  There is a 
small bubble separating the mercury into 2 parts.  A fixed DC  current,
very low, is applied and this causes the mercury to migrate across the 
air bubble very slowly.  I believe some of these devices take over
10,000 hours to move the bubble 1 inch.  The rate of migration is dependent
on the current.  BSR set the current for either 200 or 500 hours per inch.
You removed the plastic cover and moved a scale so that 0 lined up with the
bubble when you replaced your stylus.  When the bubble got near one end, 
you just unpluged the glass tube, fliped it over and pluged it in backwards.
This alway let the bubble travel left to right.  

I thought it was a neat idea.  I've seen the bubble and scale assemblies
in surplus magazines for around $2.95 less any power supplies.  You can hook
them directly to the AC  line with just a diode and a resistor, but I'd
pick a lower voltage point just to be safe.  They are small, about 
1/4 x 3/8 x 1 1/2 inches.

mikey at trsvax