Is my OPTO fried? No tach

All questions about MS2/Microsquirt/Microsquirt module. See also MS2/Extra manuals

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turbogrill
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Is my OPTO fried? No tach

Post by turbogrill »

Hi,

I have connected my Microsquirt fuel only correctly but I can't get any tach readings. I think I got it working briefly but no it's stone dead. Logs show 0 rpm.

Can I measure OPTO- and OPTO+ to see if R20 is broken or not?

I have attached the msq as well, maybe its a software error.
Matt Cramer
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Re: Is my OPTO fried? No tach

Post by Matt Cramer »

Is this a MicroSquirt? If so, your best bet is to take it out of the case and measure R20 directly.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
turbogrill
Helpful MS/Extra'er
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Re: Is my OPTO fried? No tach

Post by turbogrill »

It is microsquirt.

I measured it and it seems fried. No conductivity.

Measured a bunch of other resistors and they where all good.

This sucks, so far I have been very pleased with the quality of MS but this is definitely disappointing. I followed instructions.

Thanks for the help, I ordered a few resistors from digikey.
Matt Cramer
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Re: Is my OPTO fried? No tach

Post by Matt Cramer »

How exactly is the coil input wired up? Some configurations are less likely to cause damage than others.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
rickb794
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Re: Is my OPTO fried? No tach

Post by rickb794 »

If R20 has truely gone open you can scab a 1/4w 680 ohm resistor across the surface mount component?
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
turbogrill
Helpful MS/Extra'er
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Joined: Thu Aug 18, 2016 5:40 am

Re: Is my OPTO fried? No tach

Post by turbogrill »

Matt Cramer wrote:How exactly is the coil input wired up? Some configurations are less likely to cause damage than others.
OPTO+ directly to coil negative
OPTO- directly to coil positive (same as switched 12v)

I followed the Hardware Manual 3.4 section 6.1 (http://www.msextra.com/doc/pdf/Microsqu ... re-3.4.pdf)

I know that there is a lot of other suggestions on the forum.
Not sure who owns the manual but I would recommend adding a section "This might fry your megasquirt, these are some other more fail safe solution that might work".

I think the concept and community of Megasquirt/Microsquirt is amazing, but seems like there are few "bugs" that we need to sort out. Ideally the manual should be the golden and most correct source of information.

Car is a 280zx from the stone age, can't wait to get a working MS into it!
rickb794 wrote:If R20 has truely gone open you can scab a 1/4w 680 ohm resistor across the surface mount component?
It's not open, there is NO conductivity. I ordered some exact same resistors from Digikey. My soldering skills sucks :)
Will see how it goes.
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