Air-Core tachometer not working.

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longracing
LQFP112 - Up with the play
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Joined: Wed Jul 16, 2008 9:21 am
Location: NSW, Australia

Air-Core tachometer not working.

Post by longracing »

Has anyone played around with Autometer Tachometers?
Yes it is a 5" monster tacho, no I don't like them much, I think they are overkill, yes the car is an automatic and has an in dash tacho BUT it was given to me by a mate so I decide to humour him and install it (It is mounted down low instead of as cop-bait on the dash).

Now the config jumpers at the back are setup correctly.
The instrument light works.
The needle indicates when the button is pushed to set the shift point but it does not indicate the engine rpm. It is getting the same tach signal, from the same point as the in dash tacho.

I had a look inside, all the components look good. The only ICs are a quad Op-amp and a Air-core tach driver. I think the op-amp is used to generate the signal for the shift point and if it indicates the shift point then I believe the tach driver IC is working.

I am now wondering if the tacho signal is strong enough? I am using a signal amplifier made up of an automotive relay and transitor triggered by the MegaSquirt tach/ignition output. It works with the indash Holden Statesman tachometer but could the Autometer Gauge have a higher impedance?
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