VRIN circuit, no signal at TSEL. What about the U7 OpAmp?

[EnricGuardiaSinfreu]

An electronics novice here.

I suppose U7 (OpAmp) recives the adapted VR signal in the 3 pin input. Pin 2 is the another input used to adjust the hysterisis and voltage from the signal.
But U7 not only amplifies the signal right? It converts VR signal into a digital signal, is that correct?

Yesterday I checked the signal in VRIN (correct) and TSEL (no signal), but forgot to check on U7's pin 3. But let's suppose I get a correct signal there (I'll check it this afternoon). Which is the problem? Or is that not a problem?

If R52-R56 pots are wrongly adjusted, U7 should give a signal?



Thanks!


SOLVED THIS, BUT I HAVE MORE PROBLEMS WHILE TRYING TO SYNC VR SIGNAL (see replies)

[Matt Cramer]

This may help:

https://www.diyautotune.com/support/tec ... -tests-vr/

[EnricGuardiaSinfreu]

This may help:

https://www.diyautotune.com/support/tec ... -tests-vr/

Thanks Matt, that's exactly what I was looking for

[EnricGuardiaSinfreu]

Wow, this is really killing me, guys....

Found that Q22 had a bad solder joint so VR conditioner circuit couldn't work. Okay, my fault, it has sense. Repaired it. Checked with a 9v battery the voltages on U7's pin 1,2 and 3.

Before repairing that, pin 3 always was recieving 4.8v, because Q23 wasn't working, it was useless to use R56 pot. Now I can change the voltage on pin 3, from 4'8v to 0v. Cool. Finally I adjusted it to 3.5v.
Changing the polarity of the 9v battery, simulating AC voltage I could see pin 1 was near 5v with + power and near to 0v with whith ground. This is OK, right?

I was happy, this was going to work, finally I would sync those RPM. Plug everything on the car, TunerStudio, everything OK. Doesn't sync.
Check U7 pins.

-pin 3: didnt scope it,teorically was adjusted at 3.5v
-pin 2 its a 0 to 5v signal.
-pin 1: always 5v

Adjusted R56 all anti-clockwise, nothing, all-clockwise, nothing. I was alone so it was difficult to adjust R56 pot while cranking.


My wheel is a 60-2 (BMW) and at VRIN looks like this:





What I am doing WRONG? Have adjust the potentiometer while cranking?


Also, is there anywhere explained how MS2 interpretates the IRQ-1 signal (pin 1 U7- VROUT). What does really measure, the 5v pulse width?



Thanks so much

[Matt Cramer]

If pin 1 is stuck at 5V even if pin 2's signal can go above and below the voltage on pin 3, something is wrong with U7.

[EnricGuardiaSinfreu]

Solved this. Problems were two:

1) Due bad soldered joints, Q23 hadn't neither ground nor signal
3) Clockwised R56 pot
2) Swapped wires (ground to positve)


Now works properly.