ETX TECHNICAL TIPS Last updated: 8 September 2002

ETX-70AT Power Supply

Subject:	70at ac power adapted
Sent:	Thursday, September 5, 2002 13:54:46
From:	jtknowle@tiscali.co.uk

I have come up with a mad idea for a cheap, yet effective solution to
the battery pack.

After recently purchasing the 70 at, I have been searching around for a
viable substitute for the battery pack for indoor and backyard use. I
first scoured the past pages of the site and it would appear that most
of the suggestions are US based i.e. American specialist or based
products. Being a UK practitioner with limited knowledge of all things
electronic, I set out upon a quest to adapt a product to my ideas. I set
off down the local Maplin/Radio Shack store and threw my ideas at the
store staff. The basic idea was to take a modern ac/dc adapter
(regulated, 800amp and changeable voltages from 3-12 volts). The new
adapters have a blank connector within which you can insert a small two
pin connector to connect items such as walkman or similar electronic
device. I purchased a Uniross adapter (AD101704) as this was very small
and light. I further purchased a PP3 connector (square battery
connector), this has two bare wires which I subsequently tinned with
solder to increase their girth to fit into connector holes and add to
their conductivity. The wires have to be inserted the correct way around
in order for the correct current to travel to the components. This can
be easily tested with a multi-meter or simply pop the wires in the
adapter socket, set the adapter switch to 9 volts, plug in the adapter
and connect to the battery connector on the scope. Switch the power on
and if nothing happens then you to simply have to reverse the polarity
(switch the wires around). I then crammed in the all the wires into the
battery compartment leaving the main wire to feed through the little gap
in the battery closure lid. If the scope ends up wrapping the wire
around itself or the tripod legs then the connector acts as a stop or
you could trail the two PP3 wires through the closure lid hole so that
if the wire gets pulled the two wires should pull free from the
connector. The whole bundle takes about five minutes to setup and costs
probably around 10-12 (cheap as chips).

Cheers Jim

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