MSefi.com read only forum (Jan.15,2018)

Hello.
About year ago my MS-II 3.0 completely died.
It was a message in my Megatune "controller not found" or something like that.

It occurred gradually. For the first time it was bad engine starts, when worse and worse.
When I tried to load new firmware and then it died. No power on stim.

Now I want to use MS again.
Please help me with the answer how to repair it?
Am i need to buy new MC9S12C64 controller?

If there's no power to the stim, check the MS 5 volt rail (VCC) at pin 3 on U5. Then check there is 12v approx at pin 1. If these are both ok, check for 5 volts at the proto area.

I've seen a shorted C17 causing a burnt out track between it and U5, on a couple of occasions.

Don't worry about some expensive part having failed until you make sure the basics like the power supply is correct.

my,

You might want to read through this: http://www.megamanual.com/ms2/V3trouble.htm

Lance.

OK, I'll check these components and link.
Thanks)

trakkies wrote:If there's no power to the stim, check the MS 5 volt rail (VCC) at pin 3 on U5. Then check there is 12v approx at pin 1. If these are both ok, check for 5 volts at the proto area.

I've seen a shorted C17 causing a burnt out track between it and U5, on a couple of occasions.

Don't worry about some expensive part having failed until you make sure the basics like the power supply is correct.

When I checked first time U5:
It was 9v at on the pin nearest the DB9, 0.5 OHm at middle pin, 5v at 3rd pin.
Also it was 5v at proto area (where marked +5v)

But after couple of minutes I checked it again, and it was about 2.2v at 1st and 2nd pins of the U5.

Battery was OK after tests, 9v.


I've checked it without processor as described here http://www.megamanual.com/ms2/V3trouble.htm

===============

Now it always about 2.2v at pin 1 and 3, at proto area also 2v

Here's a more detailed test to try. 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 Cramer

I removed processor and case and checked all points except S5 (is it point on relay box?)

Here is result:
-->checking +12v
S12 = 9v
S12C = 8v
Q9 center leg = 8.5v
Q12 center leg = 8.5v
D3, left, not banded = 8.5v
U5, left leg = 7.7v
D9, left, banded end = 7.7v

-->checking +5v
S5 = ??? can't find point
two +5v holes in the proto area = 5v
D9, right, not banded end = 5v
U5, right leg = 5v
D19, left, banded end = 5v
CPU pins 1, 20, 31 = 5v

Then I installed processor, powered stim and MS started to work!!!
I downloaded and installed last version of MS Tuner Studio and I can see all parameters.
Also I downloaded my last *.msq file from MS.

I don't know what it was before, but it's working now

Thank you!

MS seems to start showing 'funnies' when the volts drop below about 8 or so. The comms seem to fail first.
Given how cheap wall warts are these days, no reason to use a PP3.

trakkies wrote:MS seems to start showing 'funnies' when the volts drop below about 8 or so. The comms seem to fail first.
Given how cheap wall warts are these days, no reason to use a PP3.

Then it died last year it was installed on the car with +12v power and tuned for daily driving.

What is PP3?