Texpis Posted October 9, 2012 Share Posted October 9, 2012 Hi All I installed the megajolt trigger wheel and mounted the coil packs, checked it and ran it all was fine at 10 deg. I loosely installed the megajolt and it worked fine communicated with the computer all okay. I then installed it neatly and now the megajolt seems to work because the timing changes when revved, there are no warning messages on the computer, it will write a map to the megajolt but it doesn't register revs or vacuum or the timing nothing changes on the display. I have checked the install and all seems okay, I have a second megajolt and that is doing the same. What have I done wrong? The computer is a Panasonic tough-book with a serial port, the engine is a rover V8 in a landrover 90. Mick Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 10, 2012 Share Posted October 10, 2012 I'd try a loopback test on the serial port (can be done with a paperclip in the end of the cable between pins 2&3) to see if something's died. It would be rare, but it could be the recieve end in the laptop has died. Can you get hold of a USB-to-RS232 adapter (preferably FTDI type) and see if it will communicate through that? Quote Link to comment Share on other sites More sharing options...
Quagmire Posted October 10, 2012 Share Posted October 10, 2012 You could probably also test it on another pc by rigging it to a batterypack or 12v supply or something. Just power it up, connect and suck on the map sensor (or use a syringe). If it communicates and you see the map value change you have 99.9% proved it works... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 10, 2012 Share Posted October 10, 2012 You don't need to suck - if it gets anything at all you know it works! At the very least the battery voltage reading should be there. Quote Link to comment Share on other sites More sharing options...
Texpis Posted October 10, 2012 Author Share Posted October 10, 2012 Hi Guys thanks for the replies I have tried it on a battery with no joy I will try a loop back test on the laptop if not I will try a USB to serial adapter Mick Quote Link to comment Share on other sites More sharing options...
Texpis Posted October 11, 2012 Author Share Posted October 11, 2012 Well I tried a USB to serial converter on a different computer with the megajolt on a battery and exactly the same so a bit stumped now. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 11, 2012 Share Posted October 11, 2012 Could be the RS-232 chip in the Megajolt (MAX-232 or compatible I think), they're not expensive (£1-£2). Quote Link to comment Share on other sites More sharing options...
Texpis Posted October 11, 2012 Author Share Posted October 11, 2012 Hmm could give that a go on the spare one will this fit the bill? http://www.maplin.co.uk/components/semiconductors/rs232-233-422 Mick Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 11, 2012 Share Posted October 11, 2012 I don't know, you'd have to look at the parts list (Bill Of Materials / BOM) for the MegaJolt you've got - I haven't built one for ages and can't remember what's inside. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 11, 2012 Share Posted October 11, 2012 Did you confirm that the USB-Serial adapter is working with a loopback test? Quote Link to comment Share on other sites More sharing options...
Texpis Posted October 11, 2012 Author Share Posted October 11, 2012 No I didnt do a loop test but I did use a different computer and a usb to serial adapter with the same results so that says its not the computer end. Mick Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 11, 2012 Share Posted October 11, 2012 Can you send messages between the two computers over the serial link (using Hyperterm / PuTTY / Terminal)? If you have a usb-serial adapter you can even do it on one computer - talk from the COM port to the USB-COM port. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 11, 2012 Share Posted October 11, 2012 No I didnt do a loop test but I did use a different computer and a usb to serial adapter with the same results so that says its not the computer end. Mick Not necessarily. Do the loopback test - for the effort required to do it, it eliminates a lot of unknowns and assumptions. Really, it's the only way you can confirm that the data is getting to the end of the cable without hooking up another computer as FF has suggested. Here's how to do it: Open a terminal (hyperterm is the Windows standard) - set it to your USB/Serial port. Speed not an issue. Jam something metal (paperclips work nicely) between pins 2+3 Type something - check it appears on your screen Remove the metal thing* Type something - check it doesn't appear on your screen *The reason for this step is that if you have 'local echo' turned on, the computer will echo back to your screen what you type. In this case, you're looking for a doubling of what you type so it'll look like this: "tthhiiss iiss aa tteesst" if it's working correctly. When you remove the paperclip, it'll look normal. You can then continue the loopback test with the MJ plugged and the processor pulled. Shorting the comm pins on the processor socket should give you the same results as above if everything is working correctly. If not - try on the MAX232 chip, both the input and output sides. Quote Link to comment Share on other sites More sharing options...
Texpis Posted October 11, 2012 Author Share Posted October 11, 2012 Hi Reckless and thaks for the reply I have done the loop test and it works fine. You last statement I need a bit more info.The processor I cant find a pin out diagram which are the comm pins? and what pins on the MAX chip? By plugged I guess you mean coms connected not powered up. Mick Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 12, 2012 Share Posted October 12, 2012 Is yours a version 4.x? If so, it's pins 6+7 on the processor socket. Check, because earlier versions have different connections. You'll need it powered up, but without the processor in the socket. Short pins 6+7 and try the loopback test as above. If it's successful then you're talking to the processor fine and you have a software problem. edit: (It's pins 11+12 on versions 2.x and 3.x) Quote Link to comment Share on other sites More sharing options...
Texpis Posted October 13, 2012 Author Share Posted October 13, 2012 Hi Reckless The megajolt communicated fine with the short on 6&7 so its a software problem we recon? Mick Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 13, 2012 Share Posted October 13, 2012 Yes - must be software. Either something on the PC side or the firmware in the MJ. I'd start by downloading a fresh version of the software, remove all traces of previous installations and reinstall. Failing that, try re-flashing the firmware to the MJ. Having never played with MJ before I can't advise on how to do this. Quote Link to comment Share on other sites More sharing options...
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