No RPM - Stim 2.21

Matt Cramer · Post by **Matt Cramer** » Mon Jan 03, 2011 9:21 am

wrongear wrote:with 5 volts applied to Techselect I have .017 volts on both sides of R12.

Check the resistance from the right side of R12 to TachSelect. It should be zero.

wrongear · Post by **wrongear** » Mon Jan 03, 2011 10:01 am

Yes, the resistance between the right side of R12 & Techselect is zero.

Matt Cramer · Post by **Matt Cramer** » Mon Jan 03, 2011 12:33 pm

What is the resistance between the left leg of R12 and ground?

wrongear · Post by **wrongear** » Mon Jan 03, 2011 5:43 pm

20 K ohms

Matt Cramer · Post by **Matt Cramer** » Tue Jan 04, 2011 5:22 am

This is weird, but I'm guessing you have a dead optoisolator.

wrongear · Post by **wrongear** » Wed Jan 05, 2011 6:18 am

"This is weird"

Does that mean that's it's checking normal & you don't see the problem. OR the trail is lost?

Matt Cramer · Post by **Matt Cramer** » Wed Jan 05, 2011 6:19 am

No, that means that you have a weird problem. And said weird problem appears to be a bad optoisolator.

wrongear · Post by **wrongear** » Wed Nov 09, 2011 7:08 pm

optoisolator U3 replaced. No change.

Matt Cramer · Post by **Matt Cramer** » Thu Nov 10, 2011 9:28 am

Do you have continuity from R12 to the optoisolator?

wrongear · Post by **wrongear** » Thu Nov 10, 2011 11:48 am

Yes. From the left side of R12 to pin 1 (top left) of U3.

Matt Cramer · Post by **Matt Cramer** » Thu Nov 10, 2011 12:52 pm

Ok. But running voltage through the optoisolator doesn't pull its output to ground?

wrongear · Post by **wrongear** » Fri Nov 11, 2011 4:59 am

Matt; I'm unsure what your asking me to do. Please re-phase your request. thanks

Matt Cramer · Post by **Matt Cramer** » Fri Nov 11, 2011 5:20 am

If you apply voltage (at least 5 volts) to the input to the optoisolator circuit (TachSelect) does the output of the optoisolator (at TSEL) go (from 5 volts) to ground (0 volts)?

wrongear · Post by **wrongear** » Mon Nov 14, 2011 8:18 am

I took 5VDC from the center post of U2 (vac manifold sensor). YES , TSEL goes to .09 volts. At the some time, I lost the IG light on the Stim & the center LED on the board lit & stayed on until power was removed.

So the answer is Yes; goes to 0.

Matt Cramer · Post by **Matt Cramer** » Mon Nov 14, 2011 8:52 am

Check if that makes it all the way to pin 14 on the U1 socket. Also, please post a copy of your current MSQ.

wrongear · Post by **wrongear** » Mon Nov 21, 2011 5:16 pm

.2 ohms from TSEL to U1,14. With 5 V jumped to TSEL, I get zero volts at 14. With no voltage jumped, I get 5 VDC at pin 14 of U1.

Matt Cramer · Post by **Matt Cramer** » Tue Nov 22, 2011 5:21 am

wrongear wrote:.2 ohms from TSEL to U1,14. With 5 V jumped to TSEL, I get zero volts at 14. With no voltage jumped, I get 5 VDC at pin 14 of U1.

Did you mean TachSelect? If not, you've got some sort of REALLY weird problem somewhere between TSEL and the U1 socket.

wrongear · Post by **wrongear** » Tue Nov 22, 2011 8:40 am

Ya, I ment Tachselect.

wrongear · Post by **wrongear** » Tue Nov 29, 2011 2:57 pm

So, what do you think Matt ???

Matt Cramer · Post by **Matt Cramer** » Tue Dec 06, 2011 6:37 am

Signal's making it to the socket. Try reloading firmware and see if that has any effect.

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No RPM - Stim 2.21

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