Can anyone here repair a Megasquirt board?`

[orava]

Hi,

I was almost finished with assembly when I think I overheated and wrecked the Q19 socket. Long story, but I now have continuity to 2 holes - i.e. I put one end of the voltmeter on the center hole and I have polarity one of the ones on the side. The continuity of the holes goes where they should outside of Q19, but obviously I have a big problem. All the sold has been removed.

Does anyone here know how to repair a board? I would be willing to pay, obviously.

Thanks

[billr]

Q19 isn't usually "socketed", are you referring to the through-holes in the board, did they get damaged? That is a fairly simple circuits, we could probably guide you in repairing the board yourself. Take good pictures of both side of the damaged area and post them if you want to consider repairing yourself.

[orava]

Thank you very much. The holes are messed up and had continuity between all of them. I think I held the iron there too long and really messed things up.

I'm not new to cars, but I am very new to soldering electronics. I scraped the holes until they were no longer showing continuity to each other, figuring the holes were useless to me now. (I had already sucked all the solder out.)

My plan is to put the Q19 into the proto area and run jumpers accordingly. I am very new to schematics, but I have this:

http://www.msextra.com/doc/general/ms1v3schems.html

I posted a picture of how I understand this to work if I jumpered it. I added the yellow line as a precaution. I think I have the numbers in the correct order on the transistors. Did I get this right? Would my plan work?

Any feedback would be very welcome. I really don't want to start over when I was so close...

[kjones6039]

Your plan to relocate Q19 to the proto area should work fine. On your schematic you posted though, you can delete the green wire along with the red one. (according to your description, Q2 is not involved so the red wire is not needed)

Ken

EDIT: got to thinking about your first post....... When you say "continuity", you are referring to ZERO resistance, aren't you?

Just took another look and you can also delete the blue line from Q19 pin 3 to Q2 pin 2. The blue wire from Q19 to R16 is all you need.

[Matt Cramer]

EDIT: got to thinking about your first post....... When you say "continuity", you are referring to ZERO resistance, aren't you?

Also - with your typical multimeter, it's hard to tell between zero resistance and the 1 ohm resistor that's across two legs of Q19.

[orava]

Thank you for the help everyone. I really appreciate it. Especially since it looks like my board can be saved. I'm learning and making mistakes, but I don't make the same mistake twice.

When you say "continuity", you are referring to ZERO resistance, aren't you?

Yes. Holes 2 and 3 on Q19 had continuity with each other with no resistance. I widened them slightly with a dremel bit to remove this continuity, since the holes were ruined already and I didn't want to risk a short.

So, just to be sure, I should wire the Q19 like this. I don't want to fry anything.



Thanks.

[orava]

Could anyone confirm that I understand this correctly? I just want to be sure before I mess something up.

Thanks

[kjones6039]

That ought to work!

Ken

EDIT: be certain when making the connections to those 2 resistors (R16 & R40) that the connection is made at the end that goes to Q2 for both resistors!

NOTE: I am suggesting here, that you connect the wires at the resistors rather than taking a chance with soldering to the Q2 pins....

[orava]

That ought to work!

Ken

EDIT: be certain when making the connections to those 2 resistors (R16 & R40) that the connection is made at the end that goes to Q2 for both resistors!

NOTE: I am suggesting here, that you connect the wires at the resistors rather than taking a chance with soldering to the Q2 pins....

Got it! Thanks!