Electronics help

[otto]

I have posted a issue with my tacho which has had no response
I really would like to have the original tacho if poss
I have one in poor cosmetic condition which I'd like to try
As stated in previous post I can't get either to work of cdi although there is 5v of the wire I don't have access to better test equipment to check pulsing
I am getting some movement on tacho (looks to be 1/4) off coil wire
The question is how can I increase this to make tacho work
Can I wire off both coils with diodes and resisters diagram would be needed
Any other options for a large 16k tacho wired off coils that will work
Do I just buy a koso rx2nr

[magg]

Why are you using a coil signal to drive OEM tacho? NC30 wiring loom has all the necessary connections provided for power and ecu signals to the tacho. A digital multimeter is unlikely to give a reliable indication of the state of the ecu tacho signal, an analogue meter should show an increasing voltage with increasing rpm.

[otto]

Can't get tacho to work of cdi Wire just shows 5 v
Only got a digital multi meter
Tried 2 different tachos
Haven't got a spare cdi to try
Just wanted to know if there was a workaround off coil
Really want to keep original rev counter
Only a track bike so might have to go for digital
Thanks for the reply thought I'd upset everyone as I had no responses to original post

[Morespeedvicar]

Could you put an led and a resistor in place of the tacho, just to see if is changes or flashes? I've never treid it! Have you metered out the wire from the cdi to the tacho?

[magg]

While you are metering out the ecu to tacho wire, check for +12VDC and earth at the OEM tacho loom connector. If after checking the wiring and confirming tacho power neither OEM tacho works, I will check my NC30 to see if Morespeedvicar LED idea can confirm a valid ecu tacho signal.

[otto]

When you say metered do you mean continuity if so yes
12v and earth all ok been redone
I'll see what I've got I can connect to cdi output
Thanks

[otto]

Just been and had another go
I definitely think gauges are ok wire to coil gauge works nice and smooth but only 1/4 of revs
Using digital multi on a tacho wire gives me steady volts when revved maybe rises 0.02 v
Good continuity between tacho wire and pin on cdi board where soldered
I'm thinking cdi why are they so damn dear and I'm so cheap