In Bill Garber wrote: >> Don't think it's that simple... I have a //c mouse that doesn't work >> on my //c, but my IIe mouse does. Both work on the IIe and Mac Plus. >> Whether it matters or not I don't know, but if you look at the model >> number of the mouse some start with "A2" and some with "M" -- >> presumably this would indicate Apple 2 or Macintosh. I've always >> suspected the problem (in my case) is with the mouse port on the //c... >> since it doubles as the game port maybe there's bug. > > Possibly ones with an A2 number will work but I also > was under the distinct impression that since the IIc's > game port doubles as a mouse port that the mouses > were wired differently. All I know for sure is that all > the M0100 mouses I have don't work and all the ones > marked IIe don't work and all the ones with IIc on the > label do work. So, IMHO, if you get one that is marked > IIc you run a better risk of it working. I also read about > a hack where you add a resistor or diode, can't remember > which now to the IIc motherboard and it allows either > one to work. There is also a paddle thing you can do, but > I'm not so sure I would mess with that. ;-) I now have 2 > IIc mouses that work, and 3 IIc's so I'm looking for one > more. Very little I need now but much more WANTS. On a Mac's mouse socket pins 1 and 3 are labelled as ground, and I assume the Apple mouse card is the same. On the IIc mouse/joystick connector pin 1 is used for Mouse ID (mouse) or pushbutton 1 (joystick) and pin 3 only is ground. On the third-party mouse I have pin 1 is connected directly to pin 3. This mouse works with my IIc, and is advertised to work with a Mac and Apple II mouse card as well. So it would seem for the IIc to work with a mouse, the mouse has to pull pin 1 directly to ground. I suspect that the early mice didn't have this link, and it was only added after the Apple IIc was released. A quick test with an ohmeter will verify if pins 1 and 3 are connected in the plugs of the mice you have that don't work, versus the ones that do work. From Rubywand's FAQs: What is the pinout for the IIe, //c, Laser and similar 9-pin mouses? The IIe/IIc/Mac Plus mouses can plug into the //c or IIc+ Game/Mouse Port or, on a IIe, into the 9-pin socket of a Mouse Card. When plugged into the // c or IIc+, several Game Port pins are redefined for use with a mouse.      Dsub-9 Female Socket on Computer    Dsub-9 Male Plug on Mouse      ,---------------------.          ,---------------------.      \  5   4   3   2   1  /          \  1   2   3   4   5  /       \   9   8   7   6   /            \   6   7   8   9   /        `-----------------'              `-----------------'    Mouse         Usual //c, IIc+ Game Port Function 1  MOUSE ID      Pushbutton 1 2  +5V           +5V 3  GND           GND 4  XDIR          no Game Port function on //c, IIc+;                  this TTL-compatible input can be read at $C066 5  XMOVE         Game Control 0 or PDL0 (Joystick X-axis) 6  n.c.          (no Game Port function on //c, IIc+) 7  MOUSE BUTTON  Pushbutton 0 8  YDIR          Game Control 1 or PDL1 (Joystick Y-axis) 9  YMOVE         no Game Port function on //c, IIc+;                  this TTL-compatible input can be read at $C067 -- Roger Johnstone, Invercargill, New Zealand Apple II - FutureCop:LAPD - iMac Game Wizard http://homepages.ihug.co.nz/~rojaws/ ________________________________________________________________________ "All parts should go together without forcing. You must remember that the parts you are reassembling were disassembled by you. Therefore, if you can't get them together again, there must be a reason. By all means, do not use a hammer." IBM maintenance manual, 1925