Ben,
This is the first time I've heard of polarity in T-series clocks. The
original mechanism was that of a mechanical, electrically-wound clock.
As the clock unwound its mainspring, electric contacts met and the device
ratcheted to wind the spring again. Polarity became an issue when people
started installing transistor and diodes to limit current through the
points.
If you are unsure about your clock's polarity, you can check it by
opening the case and inspecting for transistor and diode. I can't recall
which terminals of the transistor went where, but let me know what you
find and I will look up the info in a back issue of TSO where this was
written up.
Hal Kramer cleans, repairs and can modify the clocks with the transistor
and diode. He can get the clock ticking properly for you. Mine keeps time
accurately within a minute or two per month, though I too switch off
current when the car is not in use for several days or longer.
Bob
TD MkII
On Mon, 28 May 2001 19:15:02 -0700 "Laura & Ben Prince"
<blprince2@home.com> writes:
> I am told that some of the clocks on our T-cars are polarity
> sensitive and
> some are not. If the insulation surrounding the lead wire coming
> out of the
> clock is green, then the clock is supposedly not polarity sensitive.
> If the
> insulation is black, then the clock is claimed to only work with
> positive
> ground.
>
> This is important to someone considering switching to negative
> ground. If you
> have black insulation, don't count on having the clock when you
> switch. (Come
> to think of it, clock reliability is so bad anyway, perhaps it is
> academic.)
>
> The clock wire on my TF is green. Does anyone know which T-series
> MGs had
> black and which green?
>
> By the way, one thing you can do to improve the clock longevity is
> to install
> a toggle switch under the dash to turn the clock on or off. Then
> only turn it
> on when the rare occasion arises that you really need it.
>
> Thanks,
>
> Ben
> 54 TF 1500
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