*See Dave Dare's offer for a new solid state CVR for US$25.
Operation & Diagrams
CVR's power our Fuel and Temp gauges with 6 volts. There are two versions that have been superseded by superior solid state versions.
For now, let's talk about the original 'mechanicals'. They heat a bi-metal strip that cycles by passing 12-volt current to ground, much like a turn signal unit. The duty cycle is 50%, which causes the 'average voltage' to be 6-Volts. Half the time they are on, and half the time they are off. Volt meter readings at the output terminal will show 12-Volts when on, then zero for an equal time. ALL CVRs require a good ground in order to work properly. (Solid state CVR's waste less power, have short circuit protection, need no adjustment, and they deliver six volts constantly.)
1958 and 1959 Fords used the B7A-10804-B version, usually
mounted to the back of the instrument panel:
#1
#2
#3
The female connector is for
1960 Ford used the B9MZ-10804-C (the more common version we see today,
w/mounting tab at the top):
 #4The black screw is for, 'factory adjustment'. It is supposed to adjust the duty cycle by bending the stationary contact pressure against the bi-metal strip. |
 #5 |
 #6 |
 #7 |
Here is the layout as seen from the back of the dash...
#8
The Fuel and Temp gauges are nearly identical in construction,
which makes testing and troubleshooting the same for both.
 #9The gauges also use a bi-metal strip, but they are electrically isolated from ground. #9 shows the insides of the float resistor. |
 #10 |
Temp Gauge:
#11
Operation is identical to the Fuel Gauge.
New Solid State Regulators:
#12
These don't appear much different from the outside, but they
operate more accurately.
This one sells for $50 +S/H from many vendors.
*Dave Dare can retrofit your old CVR for US$25.00. Here is an example:
#13
Notice the green LED to show rock-steady 6 volts is present for
your Squarebird gauges. It also features overload and short circuit
protection.
Domestic shipping to the US is $4 which includes $50 insurance
coverage. Shipping to Australia is US$10.00.
PM simplyconnected or email to:
simplyconnected@aol.com.
CLICK HERE to see details of how Dave transforms your old 'correct mounting' CVR into one with new solid state electronics. The CVRs vendors sell are generic for any brand or model car and they output five volts, not six.
