orbitalgun Posted June 30, 2013 Report Share Posted June 30, 2013 Group, Thanks for reading this. Is there a troubleshooting thread, if so please re-diriect aka bump, I've noticed many bits and pieces here and there but wonder if I'm overlooking the obvious. In building my second GMx5x5, I cannot get the main LED to light, however all others do. It seems there may be a short somewhere on the main lines but tracing continuity doesn't concur. Caps are properly polarized as are diodes. Hex converters and iso opts are proven tested in first unit, which works perfectly. I'm concerned I may have a bad main chip. This is a rev 1.12 board. Suggestions are welcome. I also notice a chip replacement order up but very slowly filling. If anyone has a spare chip for sale I might be interested. Best regards, Jon Pyre, Orbitalgun. Quote Link to comment Share on other sites More sharing options...
TK. Posted June 30, 2013 Report Share Posted June 30, 2013 Hi, you could use another LED to test this. See also this schematic: http://www.ucapps.de/mbhp/mbhp_usb_gm5.pdf Just connect the cathode via a 220 resistor with ground, and the anode with pin 13 of the GM5 chip. You don't need to solder this connection, just tap it on the pin while GM5 sends some data. Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
orbitalgun Posted July 1, 2013 Author Report Share Posted July 1, 2013 Thanks for your response Thorsten, Sorry for being vague, I know the main power LED is good. I proved it out of circuit. All RCV LEDs are constantly lit. Nothing blinks, no comms, no recognition of GMx5x5 in Windows 7 or Windows XP device managers. I'm doing hard node by node this week to see if I have a bad trace somewhere, but the board looks really clean, I still think it's the main chip. Will post results as found. Best regards. JP Quote Link to comment Share on other sites More sharing options...
TK. Posted July 1, 2013 Report Share Posted July 1, 2013 Ok, I misunderstood the term "all others do" and thought, that this is only a problem with a particular LED. In fact it seems that the chip is not booting. Not so nice - it's indeed probably better if somebody could give you a replacement. 1750 GM5 chips have been sold, I don't believe that nobody could give you a spare part! ;) Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
orbitalgun Posted July 8, 2013 Author Report Share Posted July 8, 2013 Got a pair of new chips on they way. Quote Link to comment Share on other sites More sharing options...
orbitalgun Posted July 13, 2013 Author Report Share Posted July 13, 2013 That was it, I replaced the main chip and even tore a pad but was able to get the unit up by soldering the lead to the conjoining via. Thx to everyone who helped make this work out for me. I'm stoked! Now I have the excuse to possible mount both these in a single rack. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.