KPC3.1

This information amplifies a packet already sent out by KC4TMT @ W8SP.

The KPC-3 can be upgraded to 128K and a real-time clock added for about
$30 (shipping included) based on the following limitations.

1. Memory chip should be a Hitachi HM 628128LP-10, or Toshiba TC551001APL-10. 
   with a speed of 100 ns.  A faster 8f ns chip may be used but the user
   would probably never see the difference.  It is possible that a 
   Samsung KM681000/681000L-10 may work but this has not been verified. 
   Cost should be under $20 

2. The clock chip is a Dallas Semiconductors DS1215.  Cost is under $8

3. The DS1215 requires a 32.768 kHz crystal.  The load capacitance SHOULD
   be about 6 pf. for best accuracy but there is a way around this.  
   Values higher than that will cause the clock to gain or lose time.  
   Dallas Semiconductors suggests crystals from Daiwa Crystal Corporation.  
   6 pf is available, but not directly from the manufacturer.  Cost will 
   be about $1 for a 12.5 pf (like I was able to get).  6 pf are more 
   difficult to come by, but give it a try.  a 9 pf crystal is available
   from Digi-Key for about $3.

   A crystal with about 12.5 pf load factor can be compensated for using the 
   DAYTWeak command.  Over the course of several weeks, a DAYTWeak factor of  
   11 found to make the clock run fast by about .0531 seconds per hour, or 
   about 1.275 seconds fast per day.  A DAYTWeak factor of 12 made the
   clock run slow by a factor of about .093 seconds per hour, or by about 
   2.23 seconds per day.  Your may differ but it is not hard to determine
   the best setting for your crystal.

The options were purchased from JDR Microdevices 800-538-5000 as individual
pieces.  You have to order them as discrete parts.  If you request an
'update the KPC-3', they will have no idea what you are talking about.  
The part numbers are listed above.  The approximate cost was:

        SRAM        $16.95
       Clock chip    $7.95
     Crystal          $.95
         S&H         $5.00

Delivery took about 1 week.  I was unable to find a 6 pf crystal and was 
not going to order just a $3/9pf crystal from one manufacturer and the 
memory and clock from a second.  The cost of two shipping charges would have
wiped out any savings I would have realized, and I was able to compensate
for the 12.5 pf crystal using the DAYTWeak command.  

I am in no way connected with any of the distributors or manufacturers 
listed in this file. 

If anyone has any further mods, info, etc regarding the KPC-3, I would 
appreciate it if you would share it with me.  

Thanks de Bob, N1EDM @ N1KBT.#EMA.MA.USA.NA