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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Reddog on July 14, 2010, 07:49:40 AM

Title: MCI5B tach signal??
Post by: Reddog on July 14, 2010, 07:49:40 AM
Good Morning,
  So, as I continue to fiddle, the aftermarket Sun tach on the new to me bus does not work. I assume that this is basically a voltmeter driven off of some aspect of the alt/generator? (That's how it works on my backhoe). Where does the signal wire originate so I can start to diagnose the problem and what type/values of the signal should I be seeing? Thanks, Dough at 8000'
Title: Re: MCI5B tach signal??
Post by: Lin on July 14, 2010, 08:05:01 AM
If it runs off the alternator, it will be connected to the R terminal.  You might want to contact the manufacturer and find out what type of signal your tach is designed for if you do not know.  They are not all the same.
Title: Re: MCI5B tach signal??
Post by: RTS/Daytona on July 14, 2010, 08:28:56 AM
The "r" terminal output is an Inverted sine wave pulse -

Most 6V92 / 8V92-->(2.94 (53/18) gears & 6 pulses per rev=17.66 pulses/rev)
Most 24 volt - 8v71->(2.75 (55/20) gears & 6 pulses per rev=16.5  pulses/rev)
Most 12 volt - 8V71>(2.29 (55/24) gears & 6 pulses per rev=13.75 pulses/rev)

Pete RTS/Daytona