MS2V3.0-DIY-no comm but have leds and fuel/ign pulses

[Rngr4x4turbo]

I really hope someone can help with this. The ECU worked fine for 8 months until I decided to add outputs and inputs which have all now been removed. On the bench the ecu appears to be working. When I power it up on the bench the fuel pump output on db37 comes on for a couple secs, leds blink briefly and go out as usual. When I input an ign signal the ign led blinks and I get injector pulses and ign pulses(ign pulses may be a little uneven, not sure) at db37. Tried 3 computers with 2 cables and still no connection. Changed max232 and no help. All voltages are correct on rs232 ic and perfect continuity between db9 and max232. Nothing gets hot. Pin 12 on top of 40 pin connector blinks when powered up and pin 13 shows ground with no blink. I'm using led tested to check these pins. @ things I find odd, q9 and q12 have close to 12v on all 3 pins and when I try to detect controller with TS while ign signal is input it shows a lot of garbage. With no ign signal it detects nothing. About ready to toss this one because fixing it is beyond my knowledge. Oh, the vehicle it goes in is down or I would see if it is actually working. I've resoldered most connections. Thanks

[Rngr4x4turbo]

OK, more testing, when I run the 5.4.3 loopback I get 'Break Received" over and over. I also checked voltages as suggested on the forum. at I have 12v 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. I have 5V 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. Anyone care to share their thoughts?

[DaveEFI]

If MS is working normally as it seems, but no comms, you need to concentrate your tests on the comms side only.
I always use a desktop PC with proper serial port for testing as that eliminates the USB to serial adaptor. They can be source of problems even when once working, as any software updates etc to your computer might effect things. Do you know anyone with an MS so you could check your laptop and or adaptor isn't the problem?

To check U6:-

Measure volts between Pin 16 and 15
between Pin 1 & 3
between Pin 4 & 5

If all else fails, send your MS to a repairer. There's nothing on a V3 that can't be fixed easily.

[Rngr4x4turbo]

I'll check those measurements but I don't think anyone in extreme SW VA has even heard of MS..lol. I used 2 different cables on 3 different laptops all of which have been used with the mS successfully recently but they were both usb-serial. If I understand correctly the serial communications start with pins 38 and 39 on cpu and from there go to pins 12 & 13 of daughtercard 40 pin. Do you know if thats right? Thank you for replying with a helpful hand.

[Rngr4x4turbo]

volts between Pin 16 and 15 = 5v
between Pin 1 & 3 = 5v
between Pin 4 & 5 =8.5v
This is with Q9 and Q12 removed because they both had 12v on all 3 pins. Doesn't seem right to me but nobody commented on that. I have a digital scope, several DVOMs, a function generator, SMD solder station and logic level test light but without knowing what voltage or signal is supposed to be where I'm lost. If it takes a donation to get support I'm fine with that. Just ordered an MS1 cpu to try to establish comms with and also should tell me if this cpu is shot. It would be very nice if someone who knows how to test this board and cpu reply. Believe me, I've done nothing but read all the manuals and forums for months.

[Rngr4x4turbo]

Found it! As I was soldering jumpers for spare outputs under the daughterboard a piece of solder had become lodged between the 40 pin socket and the board shorting pins 13, 14 and 15 of the 40 pin socket together. Pin 13 is the rxd for serial comms. Now if I didn't burn up the 2 tip125s I'll be happy. I do have comms now and the computers recognize the controller. Live and learn. At least now I'll have a spare MS1 cpu for emergencies.