I messed up when building my MS2

Ask questions about DIY board assembly issues, fault finding and testing. (Covers all Megasquirt versions and board.)

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Coolbeans
MS/Extra Newbie
Posts: 7
Joined: Wed Jun 14, 2017 5:24 am

I messed up when building my MS2

Post by Coolbeans »

Ok, I'm not sure where I messed up, but I did. Whenever I plug in my Stim, I get what looks like a dead-short symptom - power brick lights go dim, no power on, no signal to serial. It tested fine when assembling, then I left it for a few months. Last week I figured I'd test it out (why I didn't do this before I've no idea). I've tried multiple power adapters, all show a dead short symptom - pulsing, buzzing, etc. I've been over the board a few times, I'm unable to figure it out.

It's only soldered for EDIS, I didn't want to use HEI or LS-type ignition.

Any and all help is greatly appreciated.

http://i.imgur.com/X2gyPwr.jpg
billr
Super MS/Extra'er
Posts: 6828
Joined: Sun May 15, 2011 11:41 am
Location: Walnut Creek, Calif. USA

Re: I messed up when building my MS2

Post by billr »

Remove the daughterboard (MS2) and check the voltages at the mainboard 40-pin socket again, let's see what you have there. If those voltages are all good, then the MS2 will go back in and check for the 5V again. What are you using for the "raw 12V" supply. I would also try the above tests powering the MS directly, let's get the stim out of the picture for now. Just power and ground to the MS, then com cable to the TS computer once the MS2 can go back in.

You say you "messed up", but are you just assuming that because of the present issue, or do you know you made some assembly/soldering error that had to be corrected?
prof315
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Location: Melbourne, FL

Re: I messed up when building my MS2

Post by prof315 »

Try removing the plastic hold down screws from Q9 and Q12 and lift them from the heat sink strip slightly. Then reapply power to the board. If the short goes away clean up the excess heat sink paste from around those 2 transistors and install the mica insulators. You should honestly install them regardless. if it's still broken after that and need help, I can test and repair the board.

Also you will probably find it beneficial in the long run to install everything on the board. (follow the build instructions in the manuals linked at the top of this page). You say you just want EDIS but if you fully build the ECU it can be used for other things later on if you get tired of the limitations EDIS has.
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Coolbeans
MS/Extra Newbie
Posts: 7
Joined: Wed Jun 14, 2017 5:24 am

Re: I messed up when building my MS2

Post by Coolbeans »

Lifting Q9/12 worked! I thought I had the insulators on them, guess not, fixing that now. Might as well solder on the other injection circuit, thanks everyone for the advice it is appreciated greatly.
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