MS1 v2.2 No RPM

[Liquid]

It seems that condensator c24 may be damaged, it has changed color a bit of its side. Could it cause that "black out" or is processor simply dead?

[Matt Cramer]

Matt, just confirming, i can check those voltages without processor?

Yes, you can.

[Liquid]

That's not a grounding problem, it's a short circuit. To check for a short in the Megasquirt PCB, power up the Megasquirt on a Stimulator or on the car and check the following points for voltage with a multimeter.

You should find the same voltage as the battery voltage on the following points: S12, S12C, the center legs of Q9 and Q12, the left (non-banded) end of D3, the left leg of U5, and the left (banded) end of D9.

You should have 5 volts at the following points: S5, the two +5V holes in the proto area, the right (non-banded) end of D9, the right leg of U5, the left (banded) end of D19, and pins 1, 20, and 31 of the CPU.

Let me know where you find the correct voltages, and where you find the wrong ones

Matt, could you send me a picture of the board and mark where to check, cause i cant see where in my board is s12, the two +5V holes in the proto area, s12c,s5 or Q12. I checked all i could, left leg of U5 shows 1-2 volts lover voltage than battery, bandes end of d9 shows same than battery, and i dont have D3 in my board, cause i heard its useless?

Non-banded end of D9 shows less than 4 volts, right leg of U5 shows 5 volts, D19 (LED?) shows 3,6 volts, and pins 1,20 and 31 show 5 volts.

Sorry for messy text

[Matt Cramer]

Sorry, accidentally posted the check for V3.0s! Here's what you need on a V2.2.

You should find the same voltage as the battery voltage on the following points: the small hole to the right of the larger three holes marked X11, X12, and X13, the top (non-banded) end of D20, the left leg of U5, and the left (banded) end of D12.

You should have 5 volts at the following points: the right (non-banded) end of D12, the right leg of U5, and pins 1, 20, and 31 of the CPU.

[Liquid]

5 volts are all good, battery voltage was good for that small hole and d12, d20 and left leg of u5 was about volt lower.

[Matt Cramer]

If you put the processor back in, does the 5 volt reading drop? If so, the processor is dead.

[Liquid]

5 volts are ok with or without processor, does this mean it could work with new program?

[Liquid]

YES, for the love of god, it works again but but, that u5 still gets hot, and no rpm signal. I tried that mega+stim combination in some stoneage computer with old mega code,not extra, and it puts out warning that "not same version", BUT when i move that warning away, i can adjust rpm and stuff (not saving those ofc). Is there topic or website which shows exactly what settings must be to work with stim?

[Liquid]

U5 not heating anymore, i cleaned that flux stuff from bottom.

[Liquid]

Still no rpm. I just cant fiqure out what the heck is wrong. I tryed to measure voltages of that U4, and when i touch that pin 6 it "flashes" rpm, but than nothing.

[Matt Cramer]

Try putting an LED test light on the output of the optoisolator and see if it blinks.

[Liquid]

Hmm, i have 0 voltages of opto's pin 1, shouldnt there be 2-3 voltages? anyone have same kind of problem?

[Matt Cramer]

There should be voltage on optoisolator pin 1 whenever voltage is applied to DB37 pin 24.

[Liquid]

Thanks Matt. Now there is voltage on pin24, it shows 10 voltages when input is 12v, ok? And pin1 on opto shows 1,22v, pin6 shows about 0,6v. But before, i could turn-off my stimulator with that rpm f switch, but now when i put battery on stim it waits 2 secs and then its "on", but i cant shut it down with that rpm f switch. And theres still no rpm signal on megatune.

[Liquid]

Listen up guys. Opto's pin1 shows 1,22v, pin2 ground, pin3 is useless, pin4 ground, pin5 0,05v and pin6 0,6v, is these ok?http://www.bgsoflex.com/v22/megasquirt_ShemV2.2.pdf
I have checked, and i got connections just like in that pdf shows, but still no rpm signal, or blinking leds.

[Liquid]

Matt, i tryed that led thing. I read those troubleshooting topics again, and i tested that if led flashes when taking voltages of D5. It should flash, but mine not, just stays on. So, i begin to imagine if that stimulators 555 unit is broke. I put resistor (4.5k) between pins 24 and 26, and then i grounded that pin 24 repeatably, and i saw rpm signal in megatune does this mean that my mega works, and its been that stim all the time? And is there a way to test that 555 timer works?

[Matt Cramer]

Yes, this is sounding like a Stim problem. Unfortunately, the Stim is tricky to test without an oscilloscope, other than by using the LED to check if the output blinks.

[Liquid]

Thanks. I guess that i have to buy working 555 unit or buy/borrow another stim.

[trakkies]

Thanks. I guess that i have to buy working 555 unit or buy/borrow another stim.

It can be tested - but to do so properly you need a 5 and 12v power supply - and a bit of ingenuity.

[Liquid]

Hello guys! I got a little problem with ms1 v2.2. When i try my mega on computer, everything is fine, all works etc. But, i put that mega in ford sierra 2,0 ohc, and im running with distributor, so im just controlling fuel. I´ve put wire from pin 24 to coil negative, but i cant get rpm signal => fuel pump and injectors wont work. When i turn key, fuel pump is active that 2 secs, but nothing happens when im starting. D8 is active, and i got wire from XG1-X11. I wuold appreciate some help if you guys can.

Thanks.