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Topic: '55 F-600 6Vto12V Revisited-Jon Hagan
Posted by Michael Sheik on 12-03-2006 06:56:49

I found an instrument cluster out of a 59 Ford. On the back of the steel stamped portion just above the area where the speedometer goes, is a square box 1" wide, 2" long and 3/4" thick with mounting tang on both ends for screw mount into back of stamp steel portion. Two flat spade prongs and one says IGN and other not marked and assuming this unmarked one goes to guages. Is this the 12V to 6V CVR you were talking about? Does it need to be attached (grounded) to the stamped steel portion or can it just be tie strip or taped to hold in place. NO CORRECT POLICE!
Is there a way to check that it is working off the vehicle?
I'll check back this evening!

Response: Re: '55 F-600 6Vto12V Revisited-Jon Hagan
Poster: Jon Hagen    Date: 12-03-2006 07:31:14    Thread: 22500.html
Thats the CVR. The CVR case/mount tab must be connected to a good electrical ground or it will not function. You are correct that IGN terminal is 12V in from the ignition switch,and the unmarked terminal is the common power feed for all the 6V guages. I have always tested them with the guage load connected and should indicate 6-8V at the unmarked terminal. You may need an old analog needle type volt meter to test it,the voltage is a bit lumpy and a digital volt meter may have a bit of a hard time reading that.

Response: Re: Re: '55 F-600 6Vto12V Revisited-Jon Hagan
Poster: Michael Sheik    Date: 12-03-2006 12:31:53    Thread: 22508.html
Hey Jon, Thanks for the info so far! I am going to ask more stupid questions.
After contorting myself enough to look at the back side of the cluster, I see one large green wire originating at the key switch and going over to what looks like a circuit breaker with two threaded posts.Is this green the hot wire coming in? If so, could you just splice the CVR in this wire and have 6V to all the guages, lights, etc? For the life of me I cannot see where the wire on the other threaded post is going.
On another note, the light switch has a large yellow wire that comes off one post and loops thru the amp meter ring and then to the fuel guage. I know I will have to reverse this for neg. ground.
What I would like to do is pull the inst. cluster out so I could look at and work on it easier but the 2 screws on either end do not allow you to pull it out into cab but looks like once screws removed, the cluster pushes forward and behind the dash. What am I missing here?

Response: Re: Re: Re: '55 F-600 6Vto12V Revisited-Jon Hagan
Poster: Jon Hagen    Date: 12-03-2006 16:02:55    Thread: 22512.html
The early Ford trucks I did the 6 to 12 volt conversion on were 48 model F1-F5-and F7,so I am not all that familiar with the wiring color codes on a 51 model plus the fact that I have not done one in 10-15 years,so some details have faded a bit. The CVR's load capacity is limited,so it must power only the guages. You should be able to find one wire on the cluster harness that branches to connect to 1 terminal of each of the fuel,water temp and oil pressure guage,this is the only wire that must be connected to the unmarked output terminal of the CVR. As to the wire from the ignition switch to the circuit breaker being the one that feeds the guage cluster,I don't know. I never had any problems with blowing a fuse or breaker to the guage circuit,so I never paid much attention if they are protected by an inline fuse or a small breaker. I have no shop manual for that era Ford truck,so I have no wiring diagram to check,sorry. If you could get a look at a 51 Ford wiring diagram,it would simplify what you are trying to do.

I have no experience with the neat little solid state voltage regulators Bob posted a link to. I notice that they are limited to only.75-1 amp load capacity and the Ford site saya to not connect more than 2 guages to each regulator,so you would need to install at least two.

I know the old stock Ford CVR is a rugged mechanical device that is designed to power a full set of Ford guages and is pretty much immune to damage from voltage spikes and reverse polarity,somthing the solid state regulators may not be. As I stated earlier,the stock CVR has a bit lumpy voltage output,in some machines you can see just a slight movement of the guage needles as the CVR goes through a once per second, high/low voltage cycle. In general though,they do a good job for the intended purpose.

Response: Re: Re: Re: Re: '55 F-600 6Vto12V Revisited-Jon Ha
Poster: Michael Sheik    Date: 12-03-2006 17:23:04    Thread: 22518.html
I intend to use what you have suggested. I have the parts and the more I study this and ask questions over the next 10 days the more I will know. Mine is a '55. I am going to take the 2 screws out and see if i can get a closer/better look at the wiring behind the cluster. Who knows what the previous owner did.

Response: Re: Re: '55 F-600 6Vto12V Revisited-Jon Hagan
Poster: Bob    Date: 12-03-2006 10:42:59    Thread: 22506.html
When I have converted older trucks to 12-Volts, I have used a solid-state 3-terminal voltage regulator to power the gauges.

On GM's, some type of regulator or resistor setup is a MUST ahead of the gauges, to drop the voltage, and I'm sure using it on the Fords makes like a lot easier in the IVR (Instrument Voltage Regulator), since it will now be fed the voltage it was designed for, rather than about 14-Volts.

A common regulator is the 7806.

Here's a circuit I use:

I was searching the 'net for a similar diagram, and found the FORD page linked below.

They show you nearly the same circuit, lacking the diode I use to get the extra .7 Volts, so that apparently works, too. These circuits are limited to about 1 Amp, which will easily power the gauges, and on the linked site are also diagrams for circuits to output MORE current, if needed.

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