Can't communicate with mjlj v4

Megajolt Kit assembly Question and Answers. Be sure to review the <a href="http://www.autosportlabs.net/MJLJ_V4_kit_assembly_guide">Kit assembly guide</a>

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tr3abob
Posts: 2
Joined: Sun Feb 01, 2009 12:18 am

Can't communicate with mjlj v4

Post by tr3abob »

I just finished assembling a V4 kit and all the voltages checked OK at the various stages and still do. When I connect the unit up to a laptop with a USB adapter when using the MJ software I get a "Timeout reading runtime data" which seems to point to the adapter. I then connected to my home computer with a serial port and used hyperterminal. Hyperterminal says I am connected but I get no response when I type C or S or anything. I read the post where someone popped out the processor and shorted across 2 pins and then could see whatever they typed in hyperterm but didn't say which 2 pins. Is this still a valid test and if it passes does it mean my processor is bad? I am planning on installing this in a 59 Triumph TR3 later this spring and wanted to play with the maps before then. I could do a mockup if I have to prove out that the box works otherwise but I really don't know where to go from here. Help!!
Triumph TR3A

brentp
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Post by brentp »

To do a loopback test you can remove the processor and bridge pins 6&7 of the processor socket.

Also see the schematics here: http://www.autosportlabs.net/Hard_rev_l ... Controller

You should double check the solder joints for all of the components around the RS232 transceiver (U2), especially the capacitors.

Another way to verify if the processor is basically 'alive' is to see if it controls ignition advance while the engine is running. If you have a running EDIS installation and you have the Megajolt connected to the system, you can put a timing light and observe whether ignition advance changes as you vary RPM.

Please keep us posted-

Regards,
Brent Picasso
CEO and Founder, Autosport Labs
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tr3abob
Posts: 2
Joined: Sun Feb 01, 2009 12:18 am

Post by tr3abob »

Brian,
Thanks for the tips. However, I had a senior moment, maybe 60 isn't the new 40. Anyway I had the ULN2003 and the processor swapped. Apparently I didn't hurt anything because I can now talk to the processor and see the map and I get no errors. It will be a while before I will be able to test it on a live system. Having the processor in the wrong socket would have put 5 volts on pin 9 which is labeled "PTA2/IRQ/KBI2/TCLK" on the data sheet. In my defense both socket labels end in 1. I don't know if I damaged the ULN2003 either. Any advice?
Triumph TR3A

brentp
Site Admin
Posts: 6282
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Hello,

I believe you should be OK. Once you have it on a running engine verify it's controlling ignition advance; if so, then you should be good to go.

Best regards,
Brent Picasso
CEO and Founder, Autosport Labs
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