Subject: Internal Speaker for 800XL

For anyone who'd like to put the clicker speaker back into the XL/XE, here's
how I did it on an 800XL.  It shouldn't be too hard to apply this to an XE.

1st open the machine.  If it's an 800XL, you can follow these directions.  If
yu have an XE, you'll have to ignore the component designations and track it
down yourself (post your findings for others) and come up with a place to put
the speaker where it sounds nice & loud.

The click sound comes from pin 15 of GTIA and is fed to C23 (to the right of
electrolytic C24).  To remove the click from the TV signal, remove this
capacitor.  For the internal speaker, pick the signal off the front pad of C23
with a 1K resistor (I lifted the front leg of C23 and wired an
internal/external SPDT switch). Next, you will need a small (2.5") 8ohm
speaker.  Solder a small signal diode across the terminals (RS 276-1122 or
276-1123).  To the terminal on the side of the diode with the black band,
attach a 10ohm resistor and a wire fron the other side of this resistor to +5v
(I picked 5v from the left side of decoupling capacitor C26). Next get a
2N2222 or 3904 transistor (RS 276-2009 or 276-2016) and a .001uF capacitor
(RS 272-126).  Looking at the transistor with the pins down and the flat side
facing you, solder one leg of the capacitor on the leftmost pin of the
transistor (emitter), and the other to the middle (base). Now also solder a
wire from the leftmost pin to ground (I used the right side of C26), and a 
wire from the middle pin to the 1K resistor at C23).  Connect the rightmost pin
(collector) to the terminal of the speaker that faces away from the band on the
diode. Making sure you have no shorts, power up the computer and see if you
have speaker clicks from the speaker (I reccommend heatshrink tubing around
conenctions to keep everything isolated).

Assuming everything works, continue with mounting the speaker. I placed the
speaker to the right of the cartridge slot (next to U5, the OS ROM) and stuck
it down with a couple squares of double sided foam tape (stuck to the back of
the magnet) to raise it until it just slightly pushes against the back of the
top RF shield when it's replaced.  The speaker will be noticably louder once
the shield is in place against it (8-bit acoustics).

Here's a quick diagram.

                         bottom half of speaker:
                           |   | 8ohm |   |
                           |    \____/    |
                            \            /
                              \ o-|<-o /   diode between terminals
                               /      \
               wire to 5v  ___/   ___  |
                                 |   | |
                      transistor |ebc| |
           to gnd  ______________/ | \_| collector to speaker terminal
                            |      |
                            = .001 |
                      1K    |      |
       to signal (C23 or GTIA pin 15)

Craig Lisowski (