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Discussion Starter · #1 ·
Hi Everyone, I just joined this group. I bought at 54 Mercury Sun Valley on ebay and had it shipped to California where I am working on it. My problem is that the previous owner tried to switch the battery from 6 to 12 volt. THe car starts ,but none of the guages work. Some one said I can get a diode or step down transformer to run the guages and accessories. Could some one tell me who makes these and where I could get one? Also, has anyone put one in? Thanks for your thoughts, Craig

7,345 Posts
Doc here, :pimp:

You can get an instrument regulator for Mopar, or Ford, like $50 Bucks , IIRC...It provides 6 volts out with 12 volts in..

Don't use a passive Device, like a ceramic resistor..They Generate Heat, are Big and Bulky to mount, and can cause problem down the road ...

If you want to SAVE $$, build your own..

Just get a 3 Tab Positive regulator From Rat Shak or local Electronics store, (about $2.99) , 7806 IIRC the number, or 7906 (one's positive, the other is negative regulator, don't confuse them..)

Next pay a visit to the local Confuser repair shop and ask them if they have a trashed Microprocessor and heat-sink out of an old computer..Pry the chip from the heat-sink, and you have a perfect mount for your regulator...and usually it's free..

Take it all back to the garage, Mount the Regulator on the Heat-sink Flat (non Finned ) portion, with the 3 legs extended PAST the heat-sink material. To do that , position, mark, and drill and tap a 440 hole at that spot.

Place the Mylar Gasket (should be included, if not be sure you get one) , heat-sink compound, and screw it down with a 440 screw and star washer.

Next get some 18 gauge wire , the following colors, Black, Red and Orange, about 5 feet long..strip one end, of each, and solder the RED to the Number 1 terminal, this is Switched, Fused 12 Volt power, Next get your BLACK wire, Solder that to your Number 2 Terminal, or Center Terminal..This Will Be Hard Ground. Finally Get your ORANGE wire and solder it to the number 3 terminal. This will be your gauge power. Slide Heat Shrink Tubing over all three tabs So the Terminals won't hit the heatsink and short.

Next Securely Mount your Heat-sink in close proximity to your Gauges..Drill two or four holes , low speed, All the way through the heat-sink material to handle a 6/32 or 8/32 Screw, and mount in an appropriate place, (If you don't have a flat surface, you CAN use hose Clamps on the lower Steering post.)

Now Route and Connect your wires..
  • Red = To Fused Ignition Source

  • Black = To Properly bonded , Hard Ground, use star washers.

  • Orange = To The Gauge "I" or power terminals.

There you Have it..You now have a solid state regulator For 6 Volt gauges .. That will last a lifetime, Not heat, take up less than 3 inch square of space, AND (what no passive device can do..) Regulate power to the gauges at a steady , solid 6 Volts, No matter how much load the 12 volt side See's.. (this means the gauges won't "Swing" under Differing load conditions.)

A Linear Regulator Device (which this is ) will regulate solid 6 Volts all the way down until the input voltage is LESS than 25% the output Voltage..and hold steady..This translates to about 8 volts..The Ignition Coil will quit long before the gauges drop out!

COST: about $5 Bucks! and you can have that good feeling that "I did it myself " and saved $45 bucks!

Doc :pimp:
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