Well I hope it will work with your tach.
I agree, so much more info can be gained with an actual conversation.
I must have something wrong in my head that makes me obsess over stuff like this...
If it works out, you can thank me by posting a pic of you and YR in your cheesburger hats.............!
This is the reply I got play quickly and names have been changed to protect the innocent LOL...
Hi Jpar -
I haven't run into one of these in the past.
If it can be driven with a dc voltage proportional to RPM, our TachMatch TM-03 would likely do the job. It can be triggered by the MSD.
Perhaps you could see if it responds to dc. If you have access to an adjustable dc power supply (maybe 0-10 v or so), I would connect it to the tach through a resistor (maybe 1kohm or so), then very slowly increase the voltage from 0, to see if the tach responds. The resistor would limit current to help prevent any damage to the tach. If you see no movement in one polarity, try the other. Most lab supplies also read out current, so I would keep an eye on that, and if you see current start to go up and the needle not moving, I would stop to prevent possible damage to the tach.
This would not be much different than hooking up a TachMatch with the vintage-tach adjustment set to zero, then slowing increasing the adjustment. If you would like to try this, you could buy a TachMatch ( we sell direct from our website
www.TechnoVersions.com ), try it, then return it if it doesn't work for a refund.
However, I'm guessing that it wants to see an AC voltage with frequency proportional to RPM. That would take a special circuit design which wouldn't be cost-effective in such a low volume.
A few years ago I designed an adapter for the old Smiths tachs used in Jaguars. These have an AC tachometer generator built into the engine. They drive it with AC, but the tach also works with a dc input. Hopefully you might be as lucky. On the other hand, it took 30 or 40 volts, more than a TachMatch could provide.
Regards,
Brian