TECHNICAL BULLETIN                                   COPYRIGHT   1985





DATE:                   March 14, 1985

REVISION DATE:          July 15, 1986

BULLETIN NO.:           200:2

PRODUCT:                26-3860   Tandy 200

SUBASSEMBLY:            AXX-7103   Nicad Upgrade Kit

SUBASSEMBLY REVISION:   All Revisions

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PURPOSE:   To describe installation procedures for nicad upgrade.
_________________________________________________________________________

DISCUSSION:
An option to allow the use of rechargable nicad batteries is available for
the Tandy 200.  Installation procedures are outlined below.

PROCEDURE:

Note:  The customer should be advised that this modification allows only the
use of nicad batteries in the Tandy 200.  If the customer should decide to go
back to the use of non-rechargable batteries, the modification for the use of
nicad cells will have to be removed. Both procedures are outlined below.

To install nicad batteries:

Turn the Tandy 200 over onto its top side.  Turn the memory power switch to
the "off" position;  remove any existing batteries by opening the battery
hatch cover and extracting the cells.  Remove the four (4) screws holding the
front cover to the back cover.  One is present in each corner of the back
case.  Gently remove the top cover by springing the fingers located on the
sides and the front of the machine.  Carefully detach the short spectra strip
connecting the LCD display unit to the main CPU board.  Set the top of the
machine to one side.

Move the keyboard so that the insulator and boards located below it are
exposed.  The board to be modified is the option RAM/ROM board;  this board
can be identified by the three empty sockets present on it.  To remove the
option RAM/ROM board, gently spring the two fingers holding it in place and
detach the spectra strip and cable connected to it.







                                  TB 200:2
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   TECHNICAL BULLETIN                                   COPYRIGHT   1985





Towards one end of the board is an empty switch position with two
silk-screened lines connecting two pairs of feedthroughs.  There should be a
silk-screened "Ni-Cd" in the immediate area.  Using the wire provided in the
upgrade kit, connect the pairs of feedthroughs indicated by the white
silk-screened lines.

Reassemble the computer in the reverse order of the disassembly steps.
Install the nicad batteries in the battery compartment.  Using a punch, open
the pre-stamped screw opening in the battery hatch cover.  Install the battery
hatch cover and screw it down using the screw supplied in the kit.  Install
the orange warning sticker over the screw.

Charge the batteries by attaching a DC power adapter to the computer with the
memory power turned on.  The memory power must be on in order for there to be
a complete circuit to charge the batteries.  Once the batteries are charged
check to see that the computer functions correctly using both the DC adapter
and battery power only.

To remove nicads and convert back to alkaline cells:

Turn the memory power off. Disassemble the machine as outlined above. Remove
the two jumpers installed on the empty switch position on the option RAM/ROM
board (they will be installed near the silk-screened "Ni-Cd"). Re-assemble the
machine and install alkaline cells. Remove the warning sticker from the
battery hatch cover. After turning the memory power back on, check to see that
the computer functions correctly using both the DC adapter and battery power
only.
























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