a dwell tach will give you a good reading as it is used to get your
points set right. (or your electronic dizzy set right) let the
engine idle with the dwell tach and then set your original tach to
match. you should be able to get one if you don't have one for about
$10-12.
--- Graham Stretch <technical-iwnet@lineone.net> wrote:
>
> Hi All,
> I hope one or two of you may be able to help me, I have an
> electric/electronic Smith's tacho from a Triumph 2500 P. I. saloon.
> When I
> first acquired the car the tacho would work sporadically, when it
> stopped
> working it could be awakened with a tap, later it would not wait at
> all so,
> with my limited electronic ability I managed to find the fault.
> This turned
> out to be a dry solder joint, in fixing this I managed to fry the
> component,
> so I borrowed one from a four cylinder unit. The donated component
> had
> identical markings and values, but in taking the unit apart to fix,
> I
> managed to disturb both the adjustment points, those being, the
> platform
> that adjusts the hair spring balances for the resistance to
> movement of the
> needle, and the potentiometer or rheostat (not sure which title it
> goes by,
> but there is only one adjustable electronic bit). Fee instrument
> works now
> but is wildly out on without trying to blow the engine up will only
> read
> about 2000 R. P. M.
> Can anyone tell me which of these components to adjust first and
> what values
> if any should they be set to. I have a reasonably accurate
> takeover
> checking the engine speed, I do not have access to a wave generator
> or an
> oscilloscope to simulate electrical inputs, is there any way to
> create an
> input so I don't have to rev the engine? The tacho is of the
> through feed
> type with the two bullet terminals (one male one female) and one
> Lucar
> terminal for the live feed on the back plus an earth tag on the
> case. I
> hope this is all the information you will need to be able to help.
> I have
> tried to get replacement (not very hard though) but having got it
> working
> again would love to finish the job on the basis, and I quote, "if
> someone
> made it you can repair it" as this has always been my philosophy,
> though I
> currently lack the specialist knowledge and equipment. Sorry I
> have been so
> long winded!
> !! Any thoughts on this will be welcomed!!
> Thanks in advance.
>
> Graham.
>
>
>
>
>
>
=====
nikolai jaremka
72 spitfire mkIV
east aurora, new york
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