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I am using a smiths 80mm electronic speedo with a mini spares speedo converter that plugs into the speedo housing on the gearbox. I can’t get it to work. I have tried as per the mini spares instructions (yellow to signal input on gauge (white black cable) and also added the extra feed cable (red) from the speedo to 12v as I think the mini spares is a NPN sensor and needs it (although mini spares instruction with sensor doesn’t tell you this). The gauge seems to do its startup routine and I can calibrate it ok so I don’t think it’s a gauge problem. Both gauge and sensor are new. Has anyone used this combination successfully? Any tips?

The current line of the Senders Mini Spares, that appear as and all inline molded assembly, are selling are only 1 pulse per rev and so at best will only kinda work, though usually not, with the Smiths (or just about anyone else's) Speedo. On a Mini Gearbox, they are almost useless.

You need one at a minimum that has 5 pulses per rev and preferably more.

While you may get it to work with the Mini Spares Sender, you'll find it won't read properly below about 15 kph / 10 mph, it will only tend to flicker.

You'll find one of these a better sender.

Also, just to check your wiring of the Speedo;-

Green Switched +ve
Black Earth
Red Instrument Lights
White / Black Sensor Input - this is the one to connect the Sender to.

Sender;-

Red Switched +ve (common it up with the Green of the Speedo)
Black Earth (common this up with the Black of the Speedo)
White or Yellow Connect this one to the White / Black wire of the Speedo

I never bother with the auto-calibration function. Enter in to the Manual Input mode (key OFF, hold the Trip Reset ON, Key ON, keep holding the button for about 2 - 3 seconds and you should be in this mode), then kick off with a Calibration number of about 900 and that should get you in the Ball Park, with the Speedo working. You can fine tune it from there manually after checking it works, then enter the Auto-mode.

If you use a more common (and WAY better) 6 pulse Sender, kick off with an initial number of 5000.

Thanks spider much appreciated .

I have wired as per your note and had set a calibration number of 4773 based on it claiming to be 6 pulses per rev. If it’s only 1 pulse I’ll try adjusting it and see if it then reads.

If not do you know of any better 6 pulse senders I could use?

Cheers

Andypderrick wrote: ↑Wed Jan 20, 2021 7:47 pm
If not do you know of any better 6 pulse senders I could use?

Cheers

I have to say, just about all those I've looked at, including that I linked up aren't great.

I'm in the process of developing one but I can't say how far off that is as inevitably, there'll be a few changes that are needed,,,,

<Edit: - Sorry, I thought I'd linked this up - https://www.digital-speedos.co.uk/speed ... odels-p416 - I have tried a few of these. They work OK, but don't last too well. >