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Old 05-29-2014, 08:22 AM   #1
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Default MS almost built, testing a DIY PNP?

So I've basically assembled my megasquirt using Frank's guide, and am at the point of soldering in my tyco connector. However, I've hit a bit of a mental roadblock and can't decide how I want to go from here. I've had a few friends MS their cars, one of which is going to teach me to tune mine. He has said that testing everything with the stim is pretty advisable, and that he bench tested anything new that was added, such as EBC and meth injection. The issue is, the stim uses the DB37 connector. I've already desoldered the one from the MS3X board, but as I would just be using a basic stim, that wouldn't be used anyway. The question really boils down to whether or not I solder the db37 on my board, and if I don't, how I can test my board. If I do, all of my wires for the tyco connector will have to be soldered on the bottom, and will have a very small point to solder to, and ultimately a pretty weak joint. Plan 2: Go to a junk yard, rip out a set of the MALE connectors, and make a male tyco -> DB37 adapter I can use to test with. Any suggestions?

Also, while I'm making a thread about my MS, I figured I might as well post a picture of it so if something is obviously wrong someone can yell at me. The only "mod" that was done, was soldering a 1K resisstor from the left pin of R13, to the right pin of R45, to create a 5V pullup for the VR circuit. I also have not yet added the jumpers joining S12C to JS9, TACHSELECT to VRIN, and VROUT to TSEL.

I plan on soldering the tyco connector to the MS using the schematic below.

Lastly, I soldered everything in one go, wasn't paying attention, and soldered the inductors flush with the board. When I desoldered them to raise them up,
I accidentally broke one of the magnets. The LCR meter I was using only goes to 2mH, so the readings were in the last decimal place shown, but both inductors still read within their 20% tolerances. I am replacing them both regardless when I order my IAT sensor and don't have to pay $7 shipping to get a $1 bag of components, I just haven't decided yet whether I'll run the MS in the mean time or not. Picture of broken inductor also shown below.

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MS almost built, testing a DIY PNP?-zb7gexm.jpg   MS almost built, testing a DIY PNP?-9900-standalone-ms3x.jpg   MS almost built, testing a DIY PNP?-zfik0xz.jpg  

Last edited by Schuyler; 05-29-2014 at 08:42 AM. Reason: added info about jumpers
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Old 05-30-2014, 05:59 PM   #2
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Any last minute comments? Otherwise I am just going to hook it to a 12V power supply with a 1A fuse, and do the following:

+12V goes to pin 28 and ground to any of pins 1,2,7-19 ) and measure the voltage on the 40 pin connector U1:
Put the -ve probe of you're voltmeter on pin 32 of the 40pin connector (U1) Note, this is WITHOUT the CPU card in place!
Put the +ve probe onto pin 20 (Top pin right side)
Ensure you read 5V (+- 0.1V)
d) Keep the +ve probe on pin 20 and move the -ve probe to pin 19 and pin 2, ensure you have 5V on the meter for both measurments. If its OK go to the next step (25).
After that, upload firmware, load basemap, put it in the car, see what happens? Doesn't sound like as good of an idea when I say it out loud....

Changed my mind. Probably buying a 90deg female DB37 to replace the one I desoldered, and then opposite connections for the MS3 and MS3X, and just wire those to the ecu connector. That way I can use the stim etc. later down the road.

Last edited by Schuyler; 05-30-2014 at 06:15 PM.
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