Electronic Smiths instruments

I had my Smiths electronic rev counter installed by an auto electrician and he put a diode on the power supply wire, rock steady needle at all revs.
 
YING said:
Nigel,
Do you run a filter for your electric tach?Sometimes I get a bouncing needle and Grant recommends a unit from KOSO but at $70.00 US, I want to know if this unit will help with this.
Thanks,Mike
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I have a Daytona Velona combined speedo/tacho on the 750. The tacho read erratically until I put a resistor in series in the trigger wire. Worked perfectly to stop the signal noise from affecting the tacho.

Andy
 
Thanks for all the replies on my tach.When you say “trigger wire “,is that the wire coming from the coil? Also what does a diode do in laymen’s terms.Does it just let the current go one way?
Mike
This all gets confusing.Signal filters,resistors.diodes.
 
Last edited:
Mike - I have a bunch of 4000 and 5400 series diodes which would work. I can just send you a few. Not sure how they help without knowing more about the trigger signal. It would eliminate any reverse polarity spikes.
On my bike there was a ton of noise on the 12V power wires which I think was being radiated from the plug wires. I used spiral wound inductive wires for the plugs which helped a lot. (I blew up 2 voltage monitor units before this.)
Russ
 
YING said:
Jumbo,
That package comes with 10 different diodes.Which one do you prefer?
Thanks,Mike
Click to expand...
1N4007 diode recommended by Peter Wilkinson,Caerbont Automotive Instruments Ltd. they sell the e tachs
 
I bought ring core ferrite choke lamp my rev counter used to read slow with the LED lights on good as gold now
 

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jimbo said:
1N4007 diode recommended by Peter Wilkinson,Caerbont Automotive Instruments Ltd. they sell the e tachs
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Thanks Jim,
Do I wire this diode into the wire from the coil to the tach? I am glad you got a reply from Peter as I haven’t had any response from him with other questions.
Mike
 
YING said:
Thanks Jim,
Do I wire this diode into the wire from the coil to the tach? I am glad you got a reply from Peter as I haven’t had any response from him with other questions.
Mike
Click to expand...
a diode in line with the trigger wire , diode in line with the red/blue wire
 
AndyDMC said:
I have a Daytona Velona combined speedo/tacho on the 750. The tacho read erratically until I put a resistor in series in the trigger wire. Worked perfectly to stop the signal noise from affecting the tacho.

Andy
Click to expand...
Looking back, I see it was a 1 megaohm resistor I put in the trigger wire for my Daytona.

Initially I contacted the (excellent) uk distributor who looped in the aftersales at Daytona Japan.

YMMV!

Andy
 
jimbo said:
a diode in line with the trigger wire , diode in line with the red/blue wire
Click to expand...
Jim,
Thanks for the info.Am I correct in thinking a diode just lets the current flow one way.If so,is there a correct way to wire it into that wire?Sorry for my ignorance on this. I am good at wiring but not at understanding various components and how they work.
Mike
 

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