New Member 69 Charger IVR help

[Green Charger]

Hello all. Hoping to get an answer to what I feel like is a stupid question but just want to make sure I am thinking correctly. Should there be a steady 5v out of the regulator when reading with a multi meter? I understand it is a RMS voltage and that it actually switches the 12 volts on and off in a timed sequence to average the 5v.
Just rebuilt the dash in my Charger. Installed new card from Mr. Heaterbox and solid state IVR from RTE. Fuel and temp not correct oil pressure seems to work.
Any help would be appreciated. Thanks.

 

[Nacho-RT74]

No, Voltage limiter gets a pulsating signal just like a turning flasher. The pulsations makes a 5 Volts RMS output. You can't check it with a digital tester because the sampling rate of digital multimeters won't meet the flashing rate, but just an analog tester or a test light, looking at the flashings. This won't confirm the voltage but just is in working order. You can check a dozen of VLs but everytone will have a diff flashing signal time.

I think they are adjusted with osciloscopes

Now, about the RTE unit... can't tell if is constant or also a pulsating signal

 

[Green Charger]

Thanks. I will check with a test light and see. The RTE one is supposed to duplicate the original so I assume it is pulsating. There is also a led that flashes on the back when it is working properly. Mine is flashing, so as far as I can tell it is working properly.
I am going to check the resistance for the senders at the back of the dash board as well. I found a chart on another thread that might be useful for the ohms readings. If those are good I am not sure where to go next.

 

[Nacho-RT74]

The ohms readings for senders are to be measured straight at senders. Since the only one you actually can measure and change is the fuel sender.

however I guess you could measure at wires ( purple, blue and gray ) against chassis ground to check if the ohms reading meets with what gauge should show.

 

[davek]

welcome to the site,any pics of the charger?

 

[Green Charger]

Thanks. Been reading the forum for a while so I finally decided to join. There is a ton of great info on here.The fact that my instrument circuit board burnt up helped too lol...
Here are a couple. Mine and my dad's 68.

 

[Green Charger]

Ok. Fuel guage. I read the resistance at the plug for the circuit board and on the sensor on the tank. Had 19.5 ohms at the tank and 23.8 ohms at the plug. Also measured it at the terminal on the board and got around 23 ohms. Seems the guage is not responding correctly. It should be reading somewhere between 3/4 and 1/2 at that resistance. I have resistors arriving tomorrow so I can use 5v and add resistance to see if the guage responds that way. I did test it with a battery and the needle moved smoothly for a full range of motion.
Did not get a good reading on the purple wire for the temp. I also tried at the temp sensor and did not get a good reading. The car was running and up to temp. About 160 degrees according to my laser thermometer. Will try again tomorrow as I am thinking I did not have a good ground on the meter for the temp readings.

 

[RJRENTON]

No, Voltage limiter gets a pulsating signal just like a turning flasher. The pulsations makes a 5 Volts RMS output. You can't check it with a digital tester because the sampling rate of digital multimeters won't meet the flashing rate, but just an analog tester or a test light, looking at the flashings. This won't confirm the voltage but just is in working order. You can check a dozen of VLs but everytone will have a diff flashing signal time.

I think they are adjusted with osciloscopes

Now, about the RTE unit... can't tell if is constant or also a pulsating signal

The RTE unit uses a 5 volt zener diode to provide a constant 5 volt output with 12 volts in. The origional IVR is a percent cycle timer which cycles on/off at the rate of 5/12 (40% on time 60% off time) to yield 5 volts output with 12 volts input (+/-). Accurate and dependable Zener diodes were not commercially available at the time. The IPR is nothing like a turn signal flasher which responds to current drawn by the lamp circuit to turn off then on. RMS (Root mean Squared) or average current is characteristic an AC voltage measurement; so is Peak to Peak (P to P). Most meters read in RMS or average current, regardless of being analog or digital.
BOB RENTON

 

[Billccm]

rt-eng.com claims their IVR uses a "heartbeat" switch with short circuit protection.

 

[Billccm]

The RTE unit uses a 5 volt zener diode to provide a constant 5 volt output with 12 volts in. The origional IVR is a percent cycle timer which cycles on/off at the rate of 5/12 (40% on time 60% off time) to yield 5 volts output with 12 volts input (+/-). Accurate and dependable Zener diodes were not commercially available at the time. The IPR is nothing like a turn signal flasher which responds to current drawn by the lamp circuit to turn off then on. RMS (Root mean Squared) or average current is characteristic an AC voltage measurement; so is Peak to Peak (P to P). Most meters read in RMS or average current, regardless of being analog or digital.
BOB RENTON

The RTE solid state limiter will accurately and reliably replace the original mechanical limiter. Our limiter exactly reproduces the waveform the original limiter has, including the initial warm up time that makes the gauges come up to the proper reading quickly. Other replacement limiters don’t reproduce this original warm up time.

 

[Nacho-RT74]

The IPR is nothing like a turn signal flasher which responds to current drawn by the lamp circuit to turn off then on.

Yea I know, was trying to give more less the idea about how opens and closes circuit with points and bimetallic system, not necessarily how is activated. VL gets also coil around bimetallic where flashers not, because they diff way they work.

RMS (Root mean Squared) or average current is characteristic an AC voltage measurement; so is Peak to Peak (P to P).

Nice! Didn't know! Thanks!

Most meters read in RMS or average current, regardless of being analog or digital.
BOB RENTON

Yes but the sample rate of digital is unable to sincronize with the VL pulses, so the reading is randomly shown on screen.

 

[Green Charger]

Thank you all for the info. From what I understand the RTE unit is supposed to reproduce the output of the original limiter. When I attempt to read voltage I can see it switching. There is a pattern to it and the red led is flashing so I am pretty certain it is working correctly.
I calibrated my guages using 73 ohms resistance for the low end needle position and 10 ohms for the high position. Fuel and oil pressure guage work great and temp is about 30 degrees or so off when in the car. When tested on the bench it is dead on with the same resistance and needle position listed above. My temp sensor on the water pump is reading 32 - 35 ohms when at operating temp of about 165 degrees. I think I may have higher than normal resistance in the wiring going to the dash. That is my next step. Checking the resistance in the path from sensor the dash. I think I will try and hook the guage directly to the sensor on the water pump with my 5v power source and see what it reads as well. That way it will take all the wiring out and test only the sensor and the guage.