From: joe@user.com   
      
    I may be wrong (heck, I can't remember lunch yesterday let alone this   
   stuff from 25 years ago!) but the resistor packs were not needed when   
   the controller boards had short fixed runs of cable.  Something you   
   could do with the drives in the case when there wasn't a common   
   'daisy chain' that hung outside the case.  Just put the pull-up on the   
   FDC card and it was fine.   
      
   The move to split the 'daisy chain' was probably somewhat influenced   
   by the Model II which originally kept everything on one cable, internal   
   as well as external, and had that 'terminator plug' which was actually   
   a wire-loopback.  Customers had a LOT of problems with that.  Just   
   forget to turn on the expansion disk bay and boot the machine...   When   
   attached, the bay provided the pull-ups.  However if it was 'off' then   
   the bay had 'pull-downs'.  Which included the 'write' signal and as soon   
   as you closed the door on your main drive to boot the floppy...   
      
   When the Model II FDC card was redesigned, the floppy 'chain' was   
   split into 2 isolated chains, and configurable as either 1-3 or 2-2,   
   depending on whether the card was to be used in a Model II or 16.   
      
   Mike   
      
      
   "Ian Mavric"  wrote in message   
   news:f4r5oo$2601$1@otis.netspace.net.au...   
   > Neither the Model III or 4 have internal drives that are terminated.  For   
   > whatever reason its not needed (Frank Durda IV?), only the external drives   
   > need termination.   
   >   
   > Frank - is there any benefit from adding termination to the internal drive   
   0   
   > in a Mod 3 or 4?   
   >   
   > Ian.   
   >   
   >   
   > "eugene"  wrote in message   
   > news:1181288169.072533.93560@n15g2000prd.googlegroups.com...   
   > >I just rescued a Model 4 in sad shape from an electronics recycler.   
   > > It won't boot from drive 0 and the motor is acting really strange.  I   
   > > pulled both drives out and neither one of them is terminated!  I put   
   > > in a Teac FD-55BV just for testing and it boots.  So the machine is   
   > > working.   
   > >   
   > > My question is this, I know that one of the lines that is terminated   
   > > by the resistor network is the Drive Motor Enable.  Since it isn't   
   > > being terminated this could explain the strange motor behaviour.  I   
   > > don't have a termination resistor network.  I'm assuming that it's   
   > > just a 150ohm network wired straight through?  That is, 150ohms   
   > > between pins 1 and 16, 2 and 15, etc.  I couldn't find specifications   
   > > for the resistor network in any of the TM100 documentation other than   
   > > a web site which claimed it to be 150ohms.  That seems small to me.   
   > >   
   > > Does anyone know the specifications on the termination network?   
   > >   
   >   
   >   
      
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