Thought that I would share some photos and info on the rebuild of my EB series Sun Tach Transmitter. As we all know the EB transmitters for the Sun Tach Model RC tachs use 1 or 2 (depends on if it is for a 6 Cyl or 8 Cyl) 1.35V mercury batteries which are no longer available, some guys have also used regular AA batteries but the accuracy of the tach is questionable. There are companies like the Tach Man or Williamson's Instruments who rebuild these transmitters and tach's but the cost for this is around $300 plus and if they are backlogged then you have to wait. Being a little cheap and I also like to do things myself, I found a company called RT Engineering who manufactures circuit boards to replace the old electronics in the EB series transmitter box. Their board can be mounted in the transmitter box or can be mounted on the back of the tach itself. the board is fairly accurate, off by +or- 4 RPM at a 1000 RPM and +or-16 RPM at 4000 RPM. The board will work with either 6 Volt neg ground or a 12 Volt negative ground systems, and the box no longer requires batteries inside as you use the engine ground post for your power into the box (see the wiring diagram). Please remember that the tach itself must be in working condition, there are a couple websites that tell you how to test your tach. The cost for the board is $75 and they also sell a calibration source to calibrate the tach before installation, the cost for that was $50. The guy that I dealt with was Tom, really helpful and responded quickly to questions. His email contact is: tom2@anthony-labs.com
So if you can use a soldering iron, this will be a quick and easy fix for you. Feel free to have a look at the photos and email me if you have any questions
http://s1075.photobucket.com/user/1951CanadianGMC/slideshow/Sun%20Tach%20Rebuild
