INTL 3:770/1 3:770/3   
   REPLYADDR felix@palmen-it.de   
   REPLYTO 3:770/3.0 UUCP   
   MSGID: d80f964e   
   REPLY: <95da5d03-5f32-4bdc-a10c-d64d5b033ae1o@googlegroups.com> 60de5949   
   PID: SoupGate-Win32 v1.05   
   * PaulM :   
   > Recently my C-128 has started acting very oddly, it throws random   
   > characters as if I were typing them but I'm not. Sometimes it acts   
   > like I press keys even when my fingers aren't on the keyboard, and   
   > sometimes it will add random keys among the actual keys I am typing.   
      
   I'm a software developer with only "basic" hardware knowledge, and,   
   although I own a C128, I know the C64 better, so, take the following in   
   this context…   
      
   The C128 has most of its keyboard matrix wired to a CIA (MOS 6526) I/O   
   chip called CIA #1. This chip also has all its data lines directly wired   
   to the control ports #1 and #2 (for joystick and/or mouse), therefore it   
   is directly exposed to any electrostatics on these ports. It's known to   
   break quite easily because of that. From what you describe, a broken CIA   
   #1 is kind of likely. The board has two identical chips, CIA #2 controls   
   the serial bus for peripherals like floppy drive, printer, etc -- IIRC   
   on the C128 only in C64 compatibility mode. So, a common way to be sure   
   is to exchange the two chips. If the result is keyboard/joystick/mouse   
   working perfectly while peripherals start to have problems, you know   
   your CIA chip is broken.   
      
   The problem is that many boards don't have these MOS 6526 chips   
   socketed, and unsoldering them without destroying them isn't a simple   
   task…   
      
   --   
    Dipl.-Inform. Felix Palmen ,.//..........   
    {web} http://palmen-it.de {jabber} [see email] ,//palmen-it.de   
    {pgp public key} http://palmen-it.de/pub.txt // """""""""""   
    {pgp fingerprint} A891 3D55 5F2E 3A74 3965 B997 3EF2 8B0A BC02 DA2A   
      
   --- SoupGate-Win32 v1.05   
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)   
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