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Mahmood Elnasser
06/19/12 07:34
Read: 656 times
Sacramento
USA


 
#187792 - Hardware check
Responding to: John Papas's previous message
looks like you have a hardware problem. Is the circuit new?
Was the circuit working and it got broken? usually it is hard to repair broken boards from manufacturers.
Do visual test with a magnifier there might be bad track, two data bus tracks shorted together or open, bad soldering, dry joint, broken track, swollen or cracked ic, bad electrolytic capacitor.
Use your senses, does any chip get hot, measure total current consumption of the board and compare it to the good one, if it draws too much current then usually the bad component gets hot. Since your 5v drops to 4v that means either the power supply doesn't have enough current to power the board, or one or more of the components draw too much current loading the supply.
Once you are sure your hardware is good then you start writing debug software.
I just used a microcontroller development board as IC tester, made an adapter board with 16 pin socket on my cnc and wrote code to test DS7835 chips and if pass I get a steady LED on, if fail the LED blinks. Over the years I will have a big library of non standard chips that I can't test on my ic testers.
Good luck.
Mahmood


List of 14 messages in thread
TopicAuthorDate
circuit repair, high level of all adress bytes      John Papas      06/15/12 15:16      
   what's on P2 is not that intersting initially, ...      Erik Malund      06/15/12 16:46      
      oszi daten      John Papas      06/18/12 12:16      
         depends on the app, but still      Erik Malund      06/18/12 12:51      
      we'll need a schematic, I believe.      Richard Erlacher      06/18/12 19:38      
   general guidelines      Mahmood Elnasser      06/18/12 22:45      
   RE      John Papas      06/19/12 03:39      
      Hardware check      Mahmood Elnasser      06/19/12 07:34      
      anyhow this begs a question      Erik Malund      06/19/12 09:24      
         Replay      John Papas      06/19/12 15:52      
            It wouldn't hurt to know how you've connected your hardware      Richard Erlacher      06/19/12 17:03      
               new      John Papas      06/20/12 07:12      
                  Just curious...      Hal Albach      06/20/12 07:34      
                     I have to agree with Hal, it can't be done ...      Richard Erlacher      06/20/12 09:13      

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