Transistor in rally gauge ?

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MAPS

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I don't believe I would have solved a few dilemmas with my car without the help of this clan. You guys simply...rock. If that is the term.
I seem to need a helping hand again. I have been told there is some transistor (maybe there is another term) that allow the guages to work properly.
Can someone advise me where I can buy one from.
Again, in advance thanks for all the help.
MAPS
 
or the meter match module. Different fixes for different faults.
 
You're thinking of the IVR. (Instrument Voltage Regulator) It regulates the voltage to supply 5 bolts to the gauges. I bought all the parts needed from Radio Shack for less than $5. But that was over 10 yrs ago.
It's been awhile but I think there is a simple IC, a heat sink and one more component (resistor, capacitor, something) required.
In a 67-69 cuda the stock mechanical voltage regulator is built into the gas gauge. Pretty sure on a b body it's a stand alone assembly. I performed a vasectomy inside my gas gauge to disable the stock IVR, one snip and it was no longer operable.
I think they are available for about 30 bucks if you don't want to make your own.
 
You're thinking of the IVR. (Instrument Voltage Regulator) It regulates the voltage to supply 5 bolts to the gauges. I bought all the parts needed from Radio Shack for less than $5. But that was over 10 yrs ago.
It's been awhile but I think there is a simple IC, a heat sink and one more component (resistor, capacitor, something) required.
In a 67-69 cuda the stock mechanical voltage regulator is built into the gas gauge. Pretty sure on a b body it's a stand alone assembly. I performed a vasectomy inside my gas gauge to disable the stock IVR, one snip and it was no longer operable.
I think they are available for about 30 bucks if you don't want to make your own.
Yep, RTE is not the only game in town nor the sharpest knife in the drawer. There are several solid state regulators out there with a range of features and prices. RTE is likely the only one with flashing LEDs on it ( if you think you need that ).
Nobody really needs to open the gauge to disable the mechanical limiter. To lift the gauge from the inst' housing and isolate the back of it from chassis ground serves the same purpose. Simply cover that added piece of thin metal with electric tape.
ON THE OTHER HAND... majority of the 20 ohm fuel gauges I have opened were cooked/toasted with or without a limiter inside. There duty cycle does significantly more harm than the duty cycle of oil and temp gauges. I have seen quite a few of those toasted too. Good luck with yours
 
Nice to describe your car when asking such. Yes, early cars had the Vreg inside the dash fuel gage, which lasted until ~1973 in the Rallye gages. No transistor, it is a wire heating wrapped bi-metal leaf which opens and shuts to maintain 5 V (on average) for the fuel and temp gages. I replaced w/ a $30 electronic one mounted outside from ebay (search "voltage limiter" and Plymouth). Mine has a trim pot to tweak the voltage to help perfect your fuel level reading, and those give a steady output. Some sites have photos to show how to disable in-gage Vreg (I slid heat shrink over the leaf). BTW, the later shiny rectangular cans which clip on the dash board in ~1967+, are the same thermo-electric mechanism and can similarly be replaced.
 
Lol, I'm lost....
All vehicles originally had 6 volt electrical systems. Rather than redesign/engineer the instruments when 12 volt systems came along they added a mechanical voltage limiter to power the same gauges. The limiter was housed in a rectangular metal can attached to the back of the inst' panel with 3 heavy male spades ( sort of like a household wall outlet plug ). Because the mechanical limiter worked like a set of points creating a pulse voltage, it created a electrical spike. Thus a pop noise would occur in the radio speaker. So a noise supression cap' was also added. It typically had a single screw to mount and ground it to the back of the inst' panel along with a short wire and connector terminal.
So whats different about the A-body rallye panel? The standard plug type in limiter was built to supply two thermal gauges, either two of 20 ohm gauge or one 20 ohm and one 13 ohm. The rallye panel has three of 20 ohm gauges. These have heavier needles that pivot on a post through them in 2 places. That standard limiter wouldn't work as well here. The gauges needles would be slower plus a full tank of gas versus a empty tank could make the other 2 gauges read a little different. All these so called gauges are really just simple range indicators so customer complaints was likely their only concern.
Solution... They put a special duty limiter inside this fuel gauge. The wrong limiter could not be substituted in the field.
This wasn't a new practice. They had placed limiters inside other gauges several years earlier. Imperial for one had its limiter inside the temp' gauge.
The E-body rally panel had the can type limiter but it was remotely located instead of plugged into the panel or inside a gauge. They all had some limiter somewhere.
So anyway... fast forward to modern technology and you get "the fix" suggested... Replace the mechanical limiter with solid state regulator no matter where the limiter is/was located. Result is a steady flow of reduced voltage with no spike/pop noise. No suppression cap' req'd.
 
Like I said I have no clue, but the gent the takes care of the car for me, told me it was the resistor, so I came asking here as I like to learn as much as I can... And from what I have deduced from all your help ( as usual ) is I have to buy me a Vrc 601 resistor I found on eBay. I had to do a search also to make sure that I had the right piece.
Now I have one more question.... Where does this go ? Is this soldered on the back now off the dash guages, or does it snap in somewhere ?

Again I can't say it enough, you guys literally teach me something every time I'm on this site.
Thanks.
MAPS

PS Can exchange free cadaver questions.
 
Like I said I have no clue, but the gent the takes care of the car for me, told me it was the resistor, so I came asking here as I like to learn as much as I can... And from what I have deduced from all your help ( as usual ) is I have to buy me a Vrc 601 resistor I found on eBay. I had to do a search also to make sure that I had the right piece.
Now I have one more question.... Where does this go ? Is this soldered on the back now off the dash guages, or does it snap in somewhere ?

Again I can't say it enough, you guys literally teach me something every time I'm on this site.
Thanks.
That is the limiter that plugged into the back of a standard inst' panel. Your rallye panel doesn't have that. To use that to repair your rallye panel, you'll need to mount it somewhere, and wire it in but only after the original limiter is separated from the circuit one way or another. A dead limiter is very likely to be a short circuit. Current from the new/added limiter would back feed to and through that.
I've owner a rally panel b'cuda since early 80s. I serviced a bunch of these panels for other owners for about 8 years too. Too much experience. I've seen every possible mistake and made a few of them myself.
I can't know how familiar your "gent"/mechanic is with this inst' panel so I suggest you let him read everything related to it that you can find online.
This particular inst' panel is a chore to R&R because it includes the radio and climate control bezel ( unlike the standard panel ). Its also quite fragile and booby trapped in a couple spots too. Contact pins on circuit boards are easily broken in standard or rally or any case. This rally panel has 2 circuit boards so, There's a second harness connector on left side which is too close to the top edge of the panel. Contact pins on circuit board here are very easily broken. The service manual states pull the panel outward and tilt it. They don't say how far outward.
There's a spot where the circuit board extends past the lower edge of the cast housing too. At the workbench one could easily grab the housing here and lift with one hand. Broken circuit board can result. Right handed or not, just don't. Handle with extreme care.
Even though the following will read like a money pit... I have to advise that you do everything you can do while this inst' panel is removed. Clean every contact point on the circuit boards, 8 new light bulbs and 8 new bulb sockets, lube climate controller and cables, reseal wiper pivots, all practical maintenance for a 50 yr old vehicle.
Stuff like LED bulbs, converting the ALT' gauge to a VOLTS gauge and other mods are doable also if you wish to go that far. Good luck with it.
 
Like I said, some of the sellers have detailed instructions on their sites w/ photos, for both your type and the later rectangle can type. I recall that the RTE site does/did. I recall that most come w/ Velcro sticky to attach to the back of your dash board, but you can get more elegant.
 
Hit up member moparmat2000 for a solid state IVR. He made one for my 70 Swinger cluster and it works great.

07EFAA09-BDDE-4591-9352-1F01AB049323.jpeg


95991467-D60C-4A25-9389-C04F1E0F13FF.jpeg
 
Hit up member moparmat2000 for a solid state IVR. He made one for my 70 Swinger cluster and it works great.

View attachment 1715114879

View attachment 1715114880


This looks awesome.

Redfish
Thanks for all the help/input..... And here I was thinking, this doesn't look that bad.
The mechanic I have is a good mechanic I don't think this gent will have any issues with this resistor installation.
Hell he was the one who took me about the problem so he must know what is happening. The guy knows his way around cars, even mopars. Lol.... But I'm seeing now what an ordeal this is and I thought the problem could have been solved without the dash/guages having to come off the car.
Oh well I'll let you all know what the end results will show.
I'm in the midst of recovering with a hip transplant so they're a few things more important than the car at this moment, hence the slow motion replies on my end but I shall let you all know as I stated.

Most important note of all is my Thank you ! ... To everyone here for educating me any day I'm here or anytime. Literally a school of strangers yet a course of a lifetime from friends.
MAPS
 
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