[Boatanchors] Eico 1050 power supply

[Chris Bower]

Hi all and thanks for a great list, I read all posts everyday! I'm a fairly
new Boatanchor fanatic who is currently into restoring Eico test equipment
that I remember from my Dad and Grandad's test benches. Please keep in mind
I'm somewhat new at this.

I recently found my Dad's original Eico model 1050 6v and 12v Battery
Eliminator and Charger (a 6 and 12 volt voltage adjustable power supply
designed for fairly high current, about 10 amp). Here is a link to the
schematic:
http://www.nostalgickitscentral.com/eico/schematics/eico_schematic_1050.pdf

The variable transformer in this unit is mounted to the inside of the front
panel. It has two exposed (bare copper) sections of windings on the right
and left windings on the side of the transformer that is against the front
panel. The voltage adjustment knob on the front panel turns a pair of
common contacts that wipe across these bare windings. In the 6 volt mode of
the voltage switch, a wire is connected to this rotating contact assembly
to allow adjustment of the output voltage in the 6 volt mode. This can be
seen in the schematic on the left (secondary) side of the transformer. Here
is where my question lies.

Instead of having a stationary contact to attach this wire to, it just has
a tab with a solder hole on the rotating contact plate to attach this wire!
This means that the 6 volt wire is always rotating with the voltage
adjustment knob. Of course, the wire is broken from flexing, but I can see
by the broken ends of the wire that this is, for sure, the way it was
assembled. Seems VERY unreliable to me. I know Eico cut a lot of corners in
their test equipment to keep prices down, but this seems a bit much even
for them. I asked Dad about it and he seems to remember having a lot of
trouble with the unit when using it in the 6 volt mode. He originally built
this unit from a kit but of course it was so long ago he doesn't remember
any details.

Does anyone know if this is the way this unit was designed? There is no
other sliding contacts on this rotating assembly and no other place to
solder a wire. If this is the way it was designed, can anyone suggest a
type of wire that would withstand this amount of flexing without breaking
quickly? The wire is about 8 inches long and looks to be 16 gauge or so. It
just seems strange to me that they would design it so that this wire is
connected to a contact that routienly rotates better than 200 degrees!
Thanks in advance and please keep up the great technical and nostalgic
posts in this group. It's the best part of my day sometimes!

Chris Bower
N8NW