[DSP-10] DC voltages not right

Gene Hightower gene_q_hightower at yahoo.com
Fri Mar 17 21:15:11 EST 2006


I received a new MAR-3 in the mail from Daniel Schultz, so I was able
 to finish my DSP-10 main board today.
 
 Thanks Daniel!
 
 I put 11V into the thing and...  well, no smoke, anyhow.
 
 First thing I noitice is that it's drawing only 230 mA -- so I know I
 have issues.
 
 Checking the DC voltages I find a few problems:
 
 U14 pins 2&13 read 5.37  (maybe close enough to 5.5?  dunno)
 U1 and U2 pin 3 are both 0.013V (should be 3.5 and 4.7)
 R110 reads 1.75V (should be 0.23)
 U105 pin 3 reads 2.5V (should be 3.5)
 U106 pin 3 read 4.77 (close enough to 4.6?  dunno)
 R59 reads 1.4V (should be 0.91)
 U8 pin 3 reads 2.5V (close enough to 2.8?  dunno)
 U9 pin 3 reads 3.2V (close enough to 3.6?  dunno)
 
 Everything else was spot on.
 
 I'm still new to radio and kit building, so I'm sure I've done
 something silly.  I'm going to quit for today and take a look at
 things with fresh eyes tomorrow.
 
 Any and all suggestions are welcome.  Thanks!
 
  -- Gene
 



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