From: jasen@xnet.co.nz   
      
   On 2010-03-16, thermo102  wrote:   
   >>   
   >> Else you'll need to replace the DM7400N with someething stronger;   
   >> the DM7400N chip can only produce 0.4 ma so it's not going to work,   
   >> A SN74AHC00N chip can procude 8mA on the outputs which is probably   
   >> close enough to 20mA for it to work, replace the 1K resistors with   
   >> wire links.   
   >>   
   >   
   > Thanks for your help.  My power transformer only had a rating of 1 Amp, so I   
   > picked up another one today with a rating of 4 Amps.  While at the   
   > electronics store, I also picked up a couple of the SN74AHC00N chips you   
   > mentioned.  Is the logic the same as for the DM7400N?   
   >   
   > As soon as I get the new transformer mounted and wired in, I'll remove the   
   > 1K resistors and replace with some of smaller value to see what happens.   
      
   The "74" series of logic chips have been reworked several times in   
   different variations of power ratings and speed, they all have the   
   same pinout for the same base part number.  both those parts are   
   "7400" variants, I don't recall explicitly checking the pinpouts, but   
   I did compare the written descriptions and did glance at the pinout   
   diagram, but did not make a detailed comparison.   
   www.alldatasheet.com will find you the datasheets for both parts.   
   (or just google "SN74AHC00N datasheet")   
      
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