hoohaa Posted June 28, 2007 Share Posted June 28, 2007 When connecting to either a 14v or 7v (dead 9v battery) power source through the MegaStim on my desk, the LEDs all quickly flash then die. The ignition led is the only one that remains lit. The voltage reads something like 460.2V in the realtime display in MegaTune. It does not waver or change if I switch power sources. The MS worked fine before running the MSII code. I first noticed this today after I began modding the MS2 to use the Extra code. I soldered a 12v supply jumper from the banded end of D9 to JS9 and I also soldered a jumper from DIP 40 pin 10 to JP4 in order to use JS7 (IIRC) as an extra input. After performing these mods I immediately noticed the problem the first time I plugged the MSII in. I also noticed one of the components on the DB37 side of the daugherboard (can't say which) getting hot. I thought that my MS2Extra mods had cause the problem, so I double checked what I soldered and checked the connections, everything was fine. I desoldered the DIP40 pin 10 to JP4 jumper since that was optional, and the MSII powered up normally. I then flashed the MS with MS2Extra code and left it running on 14v power for 5 minutes or so while I played with MS2Extra in MegaTune (it's cool, by the way). The MSII ran the MS2Extra code just fine during this time, all sensors behaved normally with the MegaStim pots providing normal input. Then after I had disconnected power to the MSII, the MSII began malfunctioning in the exact same way. I had not resoldered the pin 10 to jp4 jumper and I had not made any other mods to the board. I just unplugged the power to the MegaStim and plugged it back in and got the dead leds again. Checked the voltage at the megastim and the MSII and I read 14v at both places. Checked the voltage in MegaTune's realtime display and saw 460 or so volts. Most of the sensor displays were also reading absurdly high. I did not notice a hot component on the board this time. I thought at first that my MS2Extra mods had caused the problem, but when the MSII relapsed for no apparent reason I am having second thoughts. What should I check or do? Quote Link to comment Share on other sites More sharing options...
hoohaa Posted June 28, 2007 Author Share Posted June 28, 2007 Here is a blurry camera screenshot of MegaTune reading 460 volts. The pic of the MSII is showing the single ignition light. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted June 29, 2007 Share Posted June 29, 2007 I wouldnt even know where to start with this...bump. Based on my recent experience, reload the Firmware again. Quote Link to comment Share on other sites More sharing options...
naviathan Posted June 29, 2007 Share Posted June 29, 2007 I agree. Reload the firmware and also find an anti-static mat to lay your work on. At least get some helping hands and hold it off the keyboard. Quote Link to comment Share on other sites More sharing options...
hoohaa Posted June 29, 2007 Author Share Posted June 29, 2007 I knew I would get chided for not having the board on a mat. Sorry guys. I will try to do better next time. I promise that's not normal operating procedure. I'm going to try to reflash the MS2Extra code and see what happens. Wish me luck. Quote Link to comment Share on other sites More sharing options...
hoohaa Posted June 29, 2007 Author Share Posted June 29, 2007 Reflashed to MS2Extra, still no go. Reflashed to MSII code, no go. Reflashed back to MS2Extra again, the same problems. It's still not behaving normally, so I disconnected power and checked the resistors and diodes with my multimeter's ohmmeter. I get .938 ohms flowing from the banded end of D24 to the non-banded end. I get .582 ohms flowing in the normal direction. D19: .448 ohms normal direction, .496 reverse All other diodes behaved as I thought they should (what I just reported may be normal for these diodes, I had no other diodes like them to compare with). I redid the voltage check between the grounds and +5v sources on the 6 pins of the DIP40 socket as specified in the assembly guide. All checked out. Ok, after I checked all this I plugged the daughterboard back in and fired up megatune. I am now seeing 14.8 volts in the realtime display and I have working TPS, IAT, CLT pots that show expected values in the realtime displat. O2 pot does not change and reads 12.1. RPM does not change and reads "0". "IAC DC (%)" reads 100. I am thoroughly confused now. What gives? I decided to play with my 9v batteries. When I plug in a nearly dead 9v battery (7 volts), I see RPMs and O2 responding to the stim board (which I did not see when plugged into the 12v supply). I plug in a fresh 9v battery with 9.0v charge and I have no rpm nor O2. The realtime display readings seemed "unstable" when plugged into the dead 9v battery. Quote Link to comment Share on other sites More sharing options...
hoohaa Posted July 1, 2007 Author Share Posted July 1, 2007 gWell I went through the troubleshooting guide and still had the problem. Then it occurred to me to remove the +12v jumper to JS9. The MSII now works flawlessly. I don't understand this, I followed the instructions in the MS2Extra manual: I have MS2Extra code loaded, so I am not sure what I need to do. The MS seems to be functioning on the stim board without the +12v jumper right now. What a headache. I checked a lot of connections today. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted July 2, 2007 Share Posted July 2, 2007 Normally, you should take the 12 volts for the stepper IAC from pin S12© rather than D9. If you remove the jumper wire, everything except the stepper motor driver should still work. Quote Link to comment Share on other sites More sharing options...
hoohaa Posted July 3, 2007 Author Share Posted July 3, 2007 Good to know. Any thoughts on why I had this problem? Do you think it would not have been an issue had I used S12? The MS2Extra manual needs to be updated if this is true. It clearly states that the 12v lead should be taken from D9. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted July 3, 2007 Share Posted July 3, 2007 Normally, I wouldn't expect it to be an issue - although why the MS2/Extra manual recommended the left side of D9 instead of the S12C hole, I have no idea. Quote Link to comment Share on other sites More sharing options...
naviathan Posted July 5, 2007 Share Posted July 5, 2007 Something in that stepper motor circuit must be shorted and drawing too much. It shouldn't have mattered whether it's drawing from S12C or the banded end of D9 as it's essentially the same location. Check Q4 and Q20 for bridged pins and also check D8, R19 and R39 just in case. Matt - If any of these components were malfunctioning wouldn't it take out the proc as well? Or at least the associated section of it? Just curious, I'm just pulling this stuff from what I can see in the schematics. Quote Link to comment Share on other sites More sharing options...
hoohaa Posted July 6, 2007 Author Share Posted July 6, 2007 Something in that stepper motor circuit must be shorted and drawing too much. It shouldn't have mattered whether it's drawing from S12C or the banded end of D9 as it's essentially the same location. Check Q4 and Q20 for bridged pins and also check D8, R19 and R39 just in case. Do you think I still need to check these components even though I'm up and running fine now? Q4 and Q20 have been thorns in my side from the very beginning. If I could have board problems that are just lying dormant for now then I probably need to desolder those and be careful not to use too much solder this time. Quote Link to comment Share on other sites More sharing options...
naviathan Posted July 6, 2007 Share Posted July 6, 2007 Your MS is working, but you won't have idle air control until you get this circuit working. Check it out and see what the problem, otherwise you'll have issues when you do the install. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted July 6, 2007 Share Posted July 6, 2007 Something in that stepper motor circuit must be shorted and drawing too much. It shouldn't have mattered whether it's drawing from S12C or the banded end of D9 as it's essentially the same location. Check Q4 and Q20 for bridged pins and also check D8, R19 and R39 just in case. Matt - If any of these components were malfunctioning wouldn't it take out the proc as well? Or at least the associated section of it? Just curious, I'm just pulling this stuff from what I can see in the schematics. Q4, Q20, and the other on/off or PWM idle control components don't connect to 12 volts, and should not have much to do with trouble with the stepper. A stepper motor chip with a short to ground wouldn't necessarily damage the processor. The processor wouldn't be able to run as long as they are connected, but it would simply cut off the voltage to the processor unless the short caused the 12 volts to get fed to the processor pins. Quote Link to comment Share on other sites More sharing options...
naviathan Posted July 6, 2007 Share Posted July 6, 2007 So what do you think the problem could be? Maybe the UDN2916 on the daughter board? Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted July 6, 2007 Share Posted July 6, 2007 It's possible, although I think the SMT soldering is more likely to be an issue than the chip itself. Check to be sure there's no stray blobs of solder. Also try putting an ommeter between JS9 and ground; let me know what you find. You can run on/off or PWM idle control without this. Quote Link to comment Share on other sites More sharing options...
hoohaa Posted July 6, 2007 Author Share Posted July 6, 2007 I'll check on that. I'm only planning to use PWM, so that's fine. Quote Link to comment Share on other sites More sharing options...
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