[Roadsters] Alternative to Bimetallic Strip Gauge Regulator?

[RWM]

Several 1N4001 silicon rectifier diodes in series as a voltage dropping 
method makes more sense than a resistor.

In addition, a little extra attention to the OEM bi-metallic got it 
working as designed, so now I have two options.


On 4/1/2012 5:40 PM, RWM wrote:
> Verdict:  The Moss solid state gauge regulator works fine, but is a 
> little "hot"; I'll be tuning it with a dropping resistor.
>
>
> On 3/28/2012 8:44 PM, RWM wrote:
>> Now that you mention it, Charlie, I recall that.
>>
>> I'm betting there is ~2V of additional voltage drop in a 40-year old 
>> electrical harness and connectors...
>>
>> - Bob
>>
>>
>> On 3/28/2012 7:26 PM, Ken.Smart at csiro.au wrote:
>>> For reference.
>>>
>>> Those with long memories may recall Tom Walter's solid state voltage
>>> regulator. I built one many years ago based on his specs.
>>>
>>> A quick read of the Moss Motors PDF indicates that it drops the 
>>> voltage to 10v
>>> (unless I missed something )
>>>
>>> Toms original post is copied below from the list archive indicates 
>>> the need
>>> for a voltage lower than 10 somewhere around 7-8v:
>>>
>>> > From Tom Walter:
>>> I am working on a solid state replacement but don't have a good unit to
>>> compare with.
>>>
>>> Charlie,
>>>
>>> There have been a few versions of the solid state regulator made up.  I
>>> posted the version below, to which Lou in Australia pointed out a 
>>> LM7808
>>> (fixed regulator) would have saved me a few resistors. ;-)
>>>
>>> Barrie reported his roadster "liked" 7.3 volts, someone else cameback
>>> with 7.6 volts, and my
>>> car seemed to prefer closer to 8.0 volts for a fixed voltage to replace
>>> the mechanically instrument voltage regulator.
>>>
>>> Have fun!
>>>
>>> Cheers,
>>>
>>> Tom
>>>
>>> wrote this a while back:
>>>
>>>> For the voltage regulator, those electronic hobbyist
>>>> on the list should be able to make a simple replacement.
>>>>
>>>> Parts list:
>>>>
>>>> LM317T (T0-220 package)
>>>> R1 (out to adj pin)  220 Ohm
>>>> R2 (adj to gnd)     1200 Ohm
>>>> Diode (Voltage to in)  IN4007
>>>> input cap           0.1ufd  (disc  60V is fine)
>>>> output cap          1.0ufd  (tant. atleast 16V)
>>>>
>>>> For the circuit, look at a LM317 datasheet. Check the
>>>> LINEAR Databook's (Motorola, National Semiconductor, etc).
>>>> The diode just prevents reverse voltage spikes from damaging
>>>> the regulator.
>>>>
>>>> Mount the heatsink tab with mica washers (pin 2 is connected
>>>> to the tab). Output voltage is apprx 8V.
>>>>
>>> >  Note: I think the system, as a whole, was temperature
>>>> compensated. The electronic regulator may cause the gauges
>>>> to read a little higher when it is HOT outside (haven't
>>>> investigated this).
>>>>
>>>> Everything should fit back inside the original case,
>>>> keeping a stock appearance.
>>>>
>>>> For thosee who are NOT electronic hobbyist, it is still
>>>> much simplier to replace the OEM unit with one from
>>>> NISSAN (about $13).
>>>
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: datsun-roadsters-bounces at autox.team.net
>>> [mailto:datsun-roadsters-bounces at autox.team.net] On Behalf Of Roy 
>>> Haslett
>>> Sent: Thursday, 29 March 2012 7:14 AM
>>> To: Walter.Peterson; 'RWM'; 'Datsun Roadster List'
>>> Subject: Re: [Roadsters] Alternative to Bimetallic Strip Gauge 
>>> Regulator?
>>>
>>>       Thanks for the great info everyone, my fuel and temp gauges 
>>> have been
>>> indicating a little low.  This part should do the trick.
>>> Roy
>>> 67 low 1600