jrkirkish Posted May 4, 2007 Report Share Posted May 4, 2007 Pins 1 and 12 on IC 1 don't give me 5v. it's more like 250mV. I tried IC1-pin 12 to ground, and that gives me the same 250mV. I don't get it. Everything seems like it's soldered well, it's just that it's not working. Grrrr.And as an aside, my IC3 is getting really warm. Really warm. is that normal? Quote Link to comment Share on other sites More sharing options...
seppoman Posted May 4, 2007 Report Share Posted May 4, 2007 Pins 1 and 12 on IC 1 don't give me 5v. it's more like 250mV. I tried IC1-pin 12 to ground, and that gives me the same 250mV. I don't get it. Everything seems like it's soldered well, it's just that it's not working. Grrrr.Pin 12 is ground, so no wonder if you don´t get significant voltage in relation to ground :)If Pin 1 does not have 5V, there´s not many places that can be responsible for it. Look at the schematic - Pin 1 is connected to 5V via R1 (100 Ohm). So first check if the other side of R1 has the 5V, then measure the resistance of R1. If the resistance is ok, there has to be a short around R1, Pin 1 or in the 5V rail.And as an aside, my IC3 is getting really warm. Really warm. is that normal?The 7805 is supposed to get warm, but only when ICs and a LCD are connected. If it is getting warm without ICs and other boards/LCD connected, you probably have a short between 5V and Gnd somewhere. That would also explain the above problem.Do you measure 5V across IC1 Pin 11/12, IC2 Pin 5/8 or anywhere else?Seppoman Quote Link to comment Share on other sites More sharing options...
jrkirkish Posted May 4, 2007 Author Report Share Posted May 4, 2007 Wow, I'm a dumbass. I was counting the pins from the wrong corner. ::)But now I've got a similar problem: Pins 31 and 32 only read 11mV. All the other readings (taking into account that I'm now measuring the right pins) are good. Quote Link to comment Share on other sites More sharing options...
seppoman Posted May 4, 2007 Report Share Posted May 4, 2007 hmmm, it´s really unlikely that 11/12 are good and 31/32 are not - when you look at the board you see that the respective pins are directly connected below the IC. So if 11/12 are really showing 5V, then measure 31/32 again from below the board and check if you didn´t break/bend one of the 31/32 pins on the socket. You could also measure resistance (or if it has one use the beeper function of the meter) between 31/12 and 32/11 to see which of them are not connected.Seppoman Quote Link to comment Share on other sites More sharing options...
jrkirkish Posted May 4, 2007 Author Report Share Posted May 4, 2007 alright. I have infinite resistance between 31/12 and 32/11.This is not good.... maybe I should just order another CORE kit.... sigh... Quote Link to comment Share on other sites More sharing options...
seppoman Posted May 4, 2007 Report Share Posted May 4, 2007 starting over would be kind of an overreaction :) There´s almost no failure that can´t be fixed!Did you already measure on the bottom side of the board? Look at the schematic and layout pic of the core on ucapps - there are direct traces between these pins, so even if something´s wrong there it´s really unlikely that _both_ have no connection! Perhaps you started counting the pins from the wrong side again?You could post high-res closeup photos of front and backside of your board, so we could get a clue what´s the problem?Seppoman Quote Link to comment Share on other sites More sharing options...
jrkirkish Posted May 4, 2007 Author Report Share Posted May 4, 2007 Even better than photos - I have a scanner! Quote Link to comment Share on other sites More sharing options...
jrkirkish Posted May 4, 2007 Author Report Share Posted May 4, 2007 I don't believe it. I managed to screw up counting the pins AGAIN. But this time I've got it right. I have 5 V on pins 1-12, 11-12, and 31-32. Everything's golden there.I looked at this: http://www.ucapps.de/howtodebug/mbhp_core_extract_measuring_vdd.gif, and everything is good except for pin 25. that reads about half a volt.I also checked this: http://www.ucapps.de/howtodebug/mbhp_core_extract_measuring_gnd.gif and everthing seems alright.I'm just hoping somebody can look at my scans and say, "Well there's your problem"Thanks for the help, and yes, I too am surprized that I was able to put this together with such little knowledge... Quote Link to comment Share on other sites More sharing options...
stryd_one Posted May 4, 2007 Report Share Posted May 4, 2007 Give it a try mate... See if you get an upload request at power-on... Quote Link to comment Share on other sites More sharing options...
jrkirkish Posted May 4, 2007 Author Report Share Posted May 4, 2007 no, nothing. And I know it's not my computer because I tried the LED thing on the MIDI out port on the board.... it doesn't light up.I was looking at some other threads where people were having problems and I saw this:Compaired to this guys CORE, my C1 and C2 are transposed with C7 and C8. Could that be the problem? Quote Link to comment Share on other sites More sharing options...
jwillans Posted May 4, 2007 Report Share Posted May 4, 2007 The core you show is mine, and it seems to work (although I have not connected external modules yet). C1 and C2 should be 33pf and C7 and C8 should be .1uf. I'm fairly sure mine are the correct way around.James Quote Link to comment Share on other sites More sharing options...
stryd_one Posted May 5, 2007 Report Share Posted May 5, 2007 my C1 and C2 are transposed with C7 and C8. Could that be the problem?Yep!!The core you show is mineHahaha how the hell did you spot that?! I think you might have spent too much time with that thing man ;D Quote Link to comment Share on other sites More sharing options...
seppoman Posted May 5, 2007 Report Share Posted May 5, 2007 Compaired to this guys CORE, my C1 and C2 are transposed with C7 and C8. Could that be the problem?Yes! When c1/c2 are wrong value, probably the oscillator istn´t running at all -> PIC not running -> unknown behaviour/voltage of pin 25!In general I´d say most of your solder joints look ok but a little bit more soldering tin wouldn´t hurt.Seppoman Quote Link to comment Share on other sites More sharing options...
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