> On page 8-10 of the current issue of our newsletter is a cool Voltage
> Stabilizer conversion one of our members came up with
Nice article, thanks Dave & Jim. A few comments, though:
1) The NTE 1932 regulator is rated for a 2 volt dropout (typical), meaning
it can no longer supply a regulated 10 volts if the input voltage drops
below 12 volts. Since this would be a fairly common occurrence for most
Triumphs after, say, sitting at a stop light for an extended period, I feel
that a "low dropout" regulator like the NTE 1953 is more appropriate. The
NTE 1953 is rated for a 0.5 volt (typical) dropout, meaning it can supply 10
volts with an input as low as 10.5 volts. My local electronics store had
them for $3 each (although Fry's didn't).
2) There are a few minor typos in the article, eg the NTE 1932 is rated for
10.0 volts output at 1 amp; not 10.6 volts at 3 amps.
3) I recently did a similar conversion myself, but took Dan Masters'
suggestion of incorporating an LED that shows when the device has power and
ground. I also found that the NTE 1953 at least, had a tendency to
oscillate (spoiling the regulated output), so I also incorporated a 0.1
microfarad tantalum capacitor on the input. Sorry, no pictures, but I'll
take some next time.
4) It would be interesting to see data on how this conversion actually
"improves accuracy and consistency". At the very least, it seems to me that
it will _increase_ the gauge rise time after the key is turned on, since the
factory "voltage stabilizer" supplies full battery voltage for the first few
seconds, instead of only 10.0 volts. Also, since the gauges are also
thermal devices (and hence affected by temperature), the factory thermal VS
may provide for more consistent readings over a range of ambient
temperature.
But in my case, both of the VS in my parts bin were kaput, so doing the
conversion was the quick way to getting back on the road with an early TR4
temperature gauge in place of the failed aftermarket gauge on my TR3.
-- Randall
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