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Conference 7.286::atarist

Title:Atari ST, TT, & Falcon
Notice:Please read note 1.0 and its replies before posting!
Moderator:FUNYET::ANDERSON
Created:Mon Apr 04 1988
Last Modified:Tue May 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1433
Total number of notes:10312

350.0. "Don't put anything into the mouse port!!!" by UHAINA::VUJNOVIC (Slobodan Vujnovic IED/Valbonne) Fri Dec 23 1988 12:59

I plugged a LOGIMOUSE into the mouse port on my 1040, just to see what 
will happen. After all, it has the same 9-pin connector, I thought.

When I booted the machine, the mouse was dead, as well as the 
keyboard. I tried the original ST mouse, no luck.

I have probably short-circuited something. The LOGIMOUSE connector is
for the RS-232 port, but I had no idea it could do any damage. 

Has anyone tired this experiment? How bad is the damage? I would like 
to know before I take the machine to a repair shop.

Thanks in advance.
T.RTitleUserPersonal
Name		DateLines
350.1Good news and bad news.PRNSYS::LOMICKAJJeff LomickaSun Dec 25 1988 19:5624
The Logitech mouse, and also the DEC round mouse, are serial RS232 mice.
The Atari mouse is a Quadrature encoded TTL mouse.  What this means to
you is that you sent + and - 7 volts into a circuit designed to accept 0 to
+5 volts.  The negative voltage is the most likely culprit.

Now, here's the good news and the bad news:

The bad news is that the mouse port is connected directly to the pins of
the "keyboard processor", which is a separate microprocessor with mask
programming by Atari for the keyboard control.  Therefore, Atari is the
only supplier of this part.  Also, I'm not sure about this, but the
programming may be keyboard-specific.  You might need to get the FRENCH
version of this part!  I was able to get this part from a local
atari-only dealer (before he went bankrupt).

The good news is that the part is socketed, and is easily replaced by
almost anybody that can turn a screwdriver.  The part in question is the
40-pin package that is on the underside of the keyboard.  You remove the
7 screws that are in the "square-ish" holes on the underside fo the ST,
carefully separate the two halves of the case.  The keyboard is now
loose and you can easily access this chip on the underside of the
keyboard.  With a small screwdriver, you carefully pry loose the old
one, and even more carefully insert the new one.  Watch that you don't
bend any pins o allow them to slip under the chip instead of into the socket.
350.2I am ready to pay for my foolishnessUHAINA::VUJNOVICSlobodan Vujnovic IED/ValbonneMon Dec 26 1988 03:3811
Jeff, thanks for the quick answer. It doesn't sound as bad as I 
thought!

>				Also, I'm not sure about this, but the
>programming may be keyboard-specific.  You might need to get the FRENCH
>version of this part!  

In fact, the machine is a UK one; I'll try ordering the part from 
somewhere in the UK.

Regards                                          Slobodan