another No RPM problem

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Rooster210
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Re: another No RPM problem

Post by Rooster210 »

slow_hemi6 wrote:Yeah my bad for not expanding the pics, they are cropped and I could not see the point or scale, but that is why I asked the question to clarify.
21-25mV means that the 5v into pin 24 is possibly not turning off the Q22 transistor. Its a PNP so the base has to go low to conduct and if the base goes high it stops conducting. When the transistor stops conducting pin2 u7 should go high through the circuit Vcc > R48 > R44 > U7 pin 2. A bad U7 could have been shorting that to ground but as you have removed it you could just test the pin2 pad now and see what the voltage is with pin 24 grounded and with 5v.
Maybe too many cooks on this one, I had to go and paint my sons car so that's why I was out for a while.
Here's the results and actual checking so we know if Im in the right spot. The 25.7 is grounded. 26.1 is powered. The pin on the CPU socket is where im getting the 5V from. The 4.99 is my 5V source readingImageImageImageImageImage

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billr
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Re: another No RPM problem

Post by billr »

I. too, struggle with those pictures that have to be expanded to have any meaning. They aren't really adding anything anyway. I trust that you are giving the readings correctly, no need to see them on the meter face. Do include the units ("mV", for instance) in the text, though. It sure sounds like Q22 is suspect. Voltage readings at R44/48 could help to confirm that, but you already have a Q22 coming, so let's wait until you change that I, too, usually remove components "one-lead-at-a-time". Crack/cut the device case, if necessary, to get the leads separated. I hang a small hemostat (locking tweezers) to the lead so that it falls loose at the very soonest, with minimum heat.

Have you confirmed that the ground/5V that you apply to DB37-24 is getting to the base of Q22?
Rooster210
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Re: another No RPM problem

Post by Rooster210 »

billr wrote:I. too, struggle with those pictures that have to be expanded to have any meaning. They aren't really adding anything anyway. I trust that you are giving the readings correctly, no need to see them on the meter face. Do include the units ("mV", for instance) in the text, though. It sure sounds like Q22 is suspect. Voltage readings at R44/48 could help to confirm that, but you already have a Q22 coming, so let's wait until you change that I, too, usually remove components "one-lead-at-a-time". Crack/cut the device case, if necessary, to get the leads separated. I hang a small hemostat (locking tweezers) to the lead so that it falls loose at the very soonest, with minimum heat.

Have you confirmed that the ground/5V that you apply to DB37-24 is getting to the base of Q22?
I have not. I just got home so Im gonna get everything out and fiddle with it some more. Pulling Q22 and U7 out didnt make a difference in the reading. My thought now is maybe I stuck a resistor in the wrong spot or I suck at soldering.

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Rooster210
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Re: another No RPM problem

Post by Rooster210 »

Nothing on the left and middle pin of Q22. 51.4 MV on the right pin of Q22

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Rooster210
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Re: another No RPM problem

Post by Rooster210 »

Further investigation. All of these readings Im checking resistance of the resistors and comparing to the schematic from bench testing.

R13 listed as 4.7K

My reading is 45.5K and it looks like one end is burnt.

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billr
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Re: another No RPM problem

Post by billr »

Are you using the opto input at all? I would ignore R13 for now, except that if it is the wrong value, what other resistor has been swapped for it? Can you verify the color-code for R13, or is it burnt too bad?

I would still like to know if the 0/5V inputs ever get from the DB37 to the Q22 base; or measure resistance of that path with no power to the board. If that path isn't OK, then you may change Q22 and risk damaging the PCB but have no joy.
Rooster210
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Re: another No RPM problem

Post by Rooster210 »

billr wrote:Are you using the opto input at all? I would ignore R13 for now, except that if it is the wrong value, what other resistor has been swapped for it? Can you verify the color-code for R13, or is it burnt too bad?

I would still like to know if the 0/5V inputs ever get from the DB37 to the Q22 base; or measure resistance of that path with no power to the board. If that path isn't OK, then you may change Q22 and risk damaging the PCB but have no joy.
51.4 MV to the right pin of Q22 nothing else on it

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billr
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Re: another No RPM problem

Post by billr »

Is the RH pin the base? Is that with 5V to the DB37-24, or ground to the DB37-24?
Rooster210
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Re: another No RPM problem

Post by Rooster210 »

Ok guys. First off thanks for trying on this. After finding the benchtest showing all the components for the VR circuit, and finding I have at least 1 burnt resistor in that circuit, it's literally like 20 bucks to build that circuit new. The other sensors all seem to be reacting to the car turning over temp sensors are reading correct, which means as far as I can tell this circuit is the only one not working.

Since I have no clue what I messed up, it could be the resistors or capacitors, or any of the components. It could be my soldering.
Im spending 20 bucks ordering all the components and starting fresh. I know probably not necessary at all but theres too many unknowns on it. Id rather know its right and not play a chasing game if any others burn out shortly after because of whatever burnt that one

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prof315
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Re: another No RPM problem

Post by prof315 »

Has no one noticed that in the very first picture posted the 40 pin ribbon cable between the MS3 daughterboard and 3x board does NOT appear to be lined up correctly on the MS3 DB? That's generally a quick way to break stuff
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slow_hemi6
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Re: another No RPM problem

Post by slow_hemi6 »

Manual pics show that the connector edge is pretty much flush with the edge of the ms3x card and the ms3 board should have the 6 pins on the end not covered/connected. The red stripes should be at opposite ends. The manual shows the cable exiting on the sides closest to the case in one photo and the opposite side in the next photo. I am not sure that the side matters on parallel connectors, as long as they are both on the same side, should be no cross overs.
Find the Manuals up top under Quick links: Manuals. :RTFM:
Cheers Luke
Rooster210
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Re: another No RPM problem

Post by Rooster210 »

Theres a smaller 6 pin connector between the end and the edge of the card

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