Mach 1 Club
1969 - 1970 Mustang Instrument Repair and Restoration, Only! - Printable Version

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+---- Thread: 1969 - 1970 Mustang Instrument Repair and Restoration, Only! (/showthread.php?tid=1653)



1969 - 1970 Mustang Instrument Repair and Restoration, Only! - Mach 1 Club - 07-29-2010

Free Estimates, Reasonable Rates, Expert Advice, Authorized Service!
Hours: Monday-Friday 10:00 to 6:00 EST!
For Service in the U.S.: 1-800-327-8716
For Service Outside the U.S. & Local: 1-864-895-4404
[Image: tachrun.jpg]

Very informative site on Tachs and Gauges etc..

The website is a little hard to find stuff but it is worth the hunt.

MUSTANG/FORD TACHOMETERS (MOST 1963-76 FORD, 1965-73 MUSTANG) CAN CAUSE YOUR ENGINE NOT TO START. THE 12 VOLTS TO THE PLUS SIDE OF THE COIL GOES THROUGH THE TACHOMETER ELECTRONIC CIRCUIT THAT CONTAINS A SPECIAL INPUT ISOLATION TRANSFORMER. IF THE PRIMARY OF THE TRANSFORMER IS BURNED UP OR OPEN NO VOLTAGE AND THE RESULTING CURRENT FLOW WILL GET TO THE PLUS SIDE OF THE COIL. THEREFORE YOUR ENGINE WILL NOT START. THE CIRCUIT ON THE BLACK WIRE SIDE OF THE TACH GOING TO THE COIL ALSO CONTAINS A CALIBRATED BALLAST RESISTANCE BEFORE IT GETS TO THE PLUS SIDE OF THE COIL. THIS CALIBRATED RESISTANCE WIRE IS 1.5 OHMS. THE BALLAST RESISTANCE WIRE IS MADE OF TUNGSTEN TO WITH STAND HEAT. NEVER CUT THIS WIRE AS IT CAN'T BE RESTORED IN ANY WAY. THE BEST WAY TO CHECK THIS IS TO INSTALL A KNOWN GOOD TACHOMETER AND SEE IF THE ENGINE WILL START. ANOTHER WAY IS TO FIND A GOOD VOLT-OHM METER AND SELECT THE OHMS R TIMES 1 SCALE AND MEASURE ACROSS THE 2 LEADS COMING OUT OF THE TACH. IF THE METER READS OPEN OR NO RESISTANCE AT ALL, THEN THE TACH'S INTERNAL ELECTRONIC CIRCUIT IS DEFECTIVE. IF THE TACH LEADS READ AROUND 1 OHM OR SO AND THE CAR STARTS, BUT THE TACH STILL DOES NOT WORK, THEN THE TACH METER OR ELECTRONIC CIRCUIT STILL NEEDS REPAIR. IF YOU NEED TO SEND YOUR TACH TO US FOR REPAIR, YOU CAN REMOVE THE MALE AND FEMALE BANANA PLUGS FROM YOUR TACH LEADS AND JUMPER THEM TOGETHER. THE ENGINE WILL RUN WITH THE TACH OUT OF THE CIRCUIT WHILE IT IS BEING SERVICED. SINCE H&H AUTO IS AUTHORIZED FORD/MUSTANG SERVICE, WE CAN REPAIR THESE TACH'S QUICKLY AND AT AN AFFORDABLE PRICE. NEVER ALLOW ANY INSTRUMENT REPAIR SHOP TO CONVERT YOUR FORD/MUSTANG TACH TO THE MINUS SIDE OF THE COIL AS SERIOUS DAMAGE WILL OCCUR. CALL H&H AUTO AT TOLL FREE: 1-800-327-8716 OR EMAIL US AT tachman@bellsouth.net AND WE WILL REPAIR YOUR FORD TACHOMETER. ANY PARTS INSTALLED BY THE TACHMAN CARRY A 2 YEAR WARRANTY WITH EXPERT TECH ASSISTANCE!