Instrument Cluster Voltage Regulator

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Same seller, but a better PN is
http://www.ebay.com/itm/Dodge-Solid...r_Truck_Parts_Accessories&hash=item415372be9f

I need another one for my 64 Valiant, but had trouble finding it on ebay. The trick is search "voltage limiter" and "Dodge" or "Plymouth". I recall that I specified 3 ring terminals for my 65 Dart (factory limiter in fuel gage), as would williaml. For later Mopars with the rectangular can limiter, you probably want 3 male spade terminals. Note from their various PN's that this voltage limiter was not just a Mopar thing, it was the technology of the day.
 
mcnoople said:
The regulator does NOT have anything to do with your dashlights. The voltage regulator is only for the fuel and temp gauges.

Probable culprits are bad bulb, dirty contacts, bad bulb holder, bad trace on circuit board. I don't remember how much harder it is to pull the instrument cluster on a dart than a valiant, but 65 valiants are easy to pull. I would pull the cluster out clean copper where the bulb holder makes contact, clean the terminal pins where the harness plugs in, and clean the copper where the circuit board bolts to the dashface. The little nuts that the factory used are stamped steel with a very small contact area I like to change them to normal style nuts with small copper washer and some dielectric grease. And while you have the dash out replace every bulb so you don't have to go back as they fail one by one.
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What does the voltage regulator look like? I have to replace mine in my 70 Duster.
 
With a Ralley dash, it's built into the fuel gauge

With a standard dash (no oil gauge) it's a small rectangular box that plugs into the back of the PC board
 
Opened the fuel gauge up on the 65 a body. Disabled the internal instrument voltage limiter (IR) by removing the bimetallic beam on the right. The bi-metallic beam on the left is the fuel gauge mechanism, which uses the third lug (lower left when viewed from the front) for a signal from the fuel tank sending unit, (S on the back of the gauge).

RT-Eng article indicates just bending right bi-metallic beam (set of points) out of the way so they never contact again. Was going to solder something up but knew how that would end. Several nice articles on this.

Ordered one off of e-bay per Bill's link above. I think these are similar to the RT-Eng. unit :sign3:which would have been similar to the E-body rally IR with a ground lug as part of the IR case.

Specified the three ring connectors to the vendor so hopefully can mount with nuts to the outside two lugs: 5.1 volt instrument voltage (upper central lug) and 12 volt ("I" lug on back of gauge), I.e. lower right lug when viewed from the opened front (gauge face removed by drilling out two small rivets).

The external IR will bridge (replace) the former right set of points and old bi-metallic beam on the right with a solid state integrated circuit (IC). The lower right lug (I) will be at 12 volts and the upper (central) lug will be at 5 volts. The central lug will feed 5 volts to the temperature gauge and if equipped to the pressure gauge (later rally dash). The early a body will do this with the printed circuit board (PCB) trace and the later models may use actual male / female terminals. Several models may have the external IR which unplugs and a new IC can be plugged back into the back of the instrument panel PCB.

http://rt-eng.com/rte/index.php/RTE_Limiter_Faq
 
Back of instrument panel photo (rt-eng) indicating a new IC IR (RT-Eng) attached to back of instrument panel. RT-eng uses an additional lug for the noise suppression capacitor.

Installation would appear similar to original IR plug in type or moving former internal IR from inside fuel gauge to external mount on printed circuit board using two of the three fuel gauge studs I and 5v (actual mounting would be slightly different from photo).
 

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Early a body fuel gauge with IR (bi-metallic beam with heater and point contact removed). Fuel gauge beam remains to left (S stud)
 

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Clroads said:
Early a body fuel gauge with IR (bi-metallic beam with heater and point contact removed). Fuel gauge beam remains to left (S stud)
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The bimetal strip that carries the needle started out straight as an arrow. A bow in it at room temperature means it has been overheated. The gauge may still works but its like new accuracy is gone.
 
I was thinking about that. R307 looks to be original OEM style ( with points and bi-metallic beam inside). It could be used as replacement for internal IR within fuel gauge as above, just keep the noise capacitor to ignition lead and use several short leads to connect IR to studs.

Originally the integrated circuits (IC) were a simple do-it yourself forum, solder together option with approximately $5-$10 in parts (still is). Several vendors now offer several options $25 - $50ish for the integrated circuit units vs. $30 something at the auto parts store for original OEM style.
 
There are several of these out there on the various forums. The one below is one example (http://www.chargersourceguide.com/voltreg.jpg) and includes a potentiometer for fine adjustment. That IC can be placed inside or mounted to the outside of an old regulator (IR) with heat sink. The Integrated circuit (IC) is small enough to mount inside the old fuel gauge and be wired soldered to the terminals from inside the gauge for an original look. I decided to go to the outside set-up. May still try to wire one up.

http://www.chargersourceguide.com/voltagelimiter.html
 

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The voltage limiters I put in my 64 & 65 looked a bit different than in post #31. Mine was smaller, in a plastic case, w/ screw pot to adjust the output voltage. I recall <$30 on ebay from seller "prettypink" or such. In my 64, I was smarter and bench tested & tweaked the cluster temp gage using test resistors and the fuel gage against the new sender. Much easier working on the bench than with the dash in.
 
yep the charger source site is very good. the other diagram there has a surge protection diode.
 
The adjustable LM-317 regulator is a better part than the 7805 regulator circuit widely seen on the internet. The 7805 is specified as 5volts out-plus or minus 5%. That means a possible voltage output of 4.75 to 5.25 volts. If you get a 7805 that is on the low side your gauges may read lower than with the old electro-mechanical regulator.

The Charger Source Guide circuit with the short circuit protection diode looks like a good one to try. Its only disadvantage is it uses fixed resistor values to adjust the output voltage, a potentiometer would be a little more convenient. Although the fixed resistors do have the advantage that once set it will stay in proper adjustment and wont change with vibration or someone getting in there with a screwdriver.

Many of these circuits posted on the internet reference Radio Shack part numbers. With Radio Shack going bankrupt and closing so many stores these part numbers aren't going to be so useful. If anyone wants to build one of these regulators and needs help with parts, let me know.
 
the RS near me closed last sun. i got $100. of stuff list was $200. and i got two electronics parts cabinets, $300. total. but i only get one, my GF get the other. she needs it for her jewelry that she makes.
 
Just received in the mail. Potentiometer reads W 103 143C.
 

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Found these kits on the internet. $7

http://www.engineeringshock.com/lm317-variable-power-supply-kit.html

I like the idea of the printed board if using the capacitors. Wouldn't need the 4 diode bridge, and would it be okay to swap in some capacitors specified in ChargerSource above (tantalum polar capacitors)? The 1 uF 50V was not on the shelf at RS, but availible at Mouser.

Three RS's by me are going strong. One worker thought Sprint was going to buy remaining stores?
 

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No problem on changing the caps.

Just make sure you use the heatsink and put in a place where air can flow around it and it does not get too hot (like under a black metal dash in the TX sun!). When the fuel tank is full and the engine temp sensor hot ( both sensor's resistance down at or near 10 ohms) then there will be a few watts being dissipated in the regulator. It'll get hot and burn up if not heatsunk. That is one advantage of the old voltage limiter: cooler operation.
 
That heat sink in that kit looks to be a bit on the small side. As NM9 points out that heat sink will be dealing with 4 or 5 watts at times. It would take a lot of air flow to keep a sink that small cool. On the capacitors, 1 MF capacitors are below the values needed to keep the LM-317 stabile. I would go to at least 10 MF. Also, if you use tantalum types they should be rated for a least twice the voltage they will see in the circuit. Tantalums are very fragile when it comes to voltage spikes, conventional aluminum electrolytics are much more rugged.
 
RedFish said:
Fuel gauges with 3 contact/mounting posts have the voltage liniter built inside. All other typical gauges have only 2 posts. Early a-body panels and the rallye panel found in 67 through 71 second generation A-body have 3 post gauges.
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RedFish this is Boris and i have a 1964 barracuda and i have been trying to find the voltage limiter and did not realize it may be in the fuel Gage. Do you have one for sale. My fuel gage and temp gage do not work and i replaced the circuit board already. Please help
 
Boris said:
RedFish this is Boris and i have a 1964 barracuda and i have been trying to find the voltage limiter and did not realize it may be in the fuel Gage. Do you have one for sale. My fuel gage and temp gage do not work and i replaced the circuit board already. Please help
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You could search ebay for "instrument voltage regulator" and find several examples with a wide range in price. The optimal solid state instrument regulator comes from Real Time Engineering. It has LED indicators but more importantly It has ground fault protection built into its circuitry. Of course it is the most expensive too.
Any alternate regulator will need to be mounted somewhere under the dash. You will disable the original regulator and route wiring from the new regulator location to the instrument panel.
With internet research you will find pictures and info about opening your fuel gauge to disable that internal regulator but that isn't necessary. If a 3 volt battery properly attached to fuel gauge or temp gauge moves their needle to about half the range, no need to open either of them.
Post a pic of the back of your inst' panel. Remove your fuel gauge and post a pic of its backside. I can cover all the details.
 
RedFish said:
You could search ebay for "instrument voltage regulator" and find several examples with a wide range in price. The optimal solid state instrument regulator comes from Real Time Engineering. It has LED indicators but more importantly It has ground fault protection built into its circuitry. Of course it is the most expensive too.
Any alternate regulator will need to be mounted somewhere under the dash. You will disable the original regulator and route wiring from the new regulator location to the instrument panel.
With internet research you will find pictures and info about opening your fuel gauge to disable that internal regulator but that isn't necessary. If a 3 volt battery properly attached to fuel gauge or temp gauge moves their needle to about half the range, no need to open either of them.
Post a pic of the back of your inst' panel. Remove your fuel gauge and post a pic of its backside. I can cover all the details.
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Thank you for this information and the link to real time engineering. I will post pictures when i pull out the panel. Thanks again.
 
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