Author Topic: Repro tach burned out  (Read 3751 times)

jdv69z

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Re: Repro tach burned out
« Reply #15 on: September 16, 2016, 07:27:34 PM »
Going from memory here. how many wires does the tach come with? I'm thinking 4 - one for power, one for ground, one for the back lighting, and one for the signal which comes from the negative side of the coil? Am I close?
Jimmy V.

lemarin

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Re: Repro tach burned out
« Reply #16 on: September 16, 2016, 08:12:22 PM »
From my understanding you're right. The one for the light is independent from the other 3, at least on my car (repro kit for clock, tack and center instruments).  Behind the tach, there's a plug with 3 wires: one going to negative of the ignition coil, one ground, and the third one going to the fuse circuit.
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69Z28-RS

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Re: Repro tach burned out
« Reply #17 on: September 16, 2016, 08:16:53 PM »
You might need to filter the Pertronix output for your repro tach...  Can you inquire with the manufacturer??
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jdv69z

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Re: Repro tach burned out
« Reply #18 on: September 16, 2016, 08:32:00 PM »
So if the power wire is "downstream" of the ignition switch, meaning it is turned off when the key is off, try turning on the key to supply power and then reading the voltage between the ground and power wires. Should read approx 12V. Set meter to measure volts DC. (not AC) If it needs a range, try 0 to 50 volts, I don't think the lighting wire would have any effect here, it merely powers the bulb. If the voltage measurement checks out, the signal wire has to be the source of the problem; maybe for some reason your ignition setup is putting out too much voltage for the tach and burning it up? You could try measuring voltage between the signal wire and ground as well. Again volts DC. I think Gary's idea of checking with Pertronix is a sound one as well. Maybe you need resistor of some kind?
Jimmy V.

lemarin

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Re: Repro tach burned out
« Reply #19 on: September 17, 2016, 03:06:59 PM »
Thanks to all with the suggestions /trick to help me fix my problem. It may take few weeks before I receive my new tach and make all these tests.

If I decide to add a tach filter, do you guys have a suggested brand and model to buy ? Also on which wires is it connected to ?
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lemarin

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Re: Repro tach burned out
« Reply #20 on: September 17, 2016, 06:47:31 PM »
I spoke with Pertronix, and here's their answer: The Ignitors will not cause the tachometers to fail, its the same signal as with points. Check your wiring and insure that everything is connected properly according to the tachometer manufacturer.
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lemarin

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Re: Repro tach burned out
« Reply #21 on: May 29, 2018, 02:26:14 PM »
*update*

Finally found my answer recently, and it now works perfectly ! I'm so happy. I could ear a strange noise/sound coming out of my engine, and did not really care about for while. Then I realized it was related with the tach, as the needle was moving together with the sound...

That's my current regulator that was toasted and doing this noise, and probably sending more peak power to the 12V panel....and burn out 2 tach !

I changed it and everything works great, I'm so happy !
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PURESS

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Re: Repro tach burned out
« Reply #22 on: May 29, 2018, 07:14:20 PM »
Good to hear

67jeffreyt

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Re: Repro tach burned out
« Reply #23 on: May 30, 2018, 11:38:16 PM »
My electronic conversion box is a crane xri, with their aftermarket coil you are required to keep the resistance wire in place. I'm not sure on pertronix, the resistor wire is required for the coil not the ignition piece.
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