TR-707 ROM Expansion Page 6
Installation
Reinstall the main PCB assembly in the top case, reconnecting the two cables that join it to
the panel board. Like the disassembly, this is easiest done with the machine on end. Plug
the ribbon cable into the expansion board.
Replace the screws that secure the PCB assembly in the top case, which you removed in
Step 5, also replacing the ground wire(s).
11.
Replace the cartridge connector and reconnect the at ex ribbon.
Re-solder the wires to the battery compartment.
12.
Replace the bottom cover, 7x case screws, and slider caps, and put the two AA cells
back in the battery compartment.
13.
When powering up the machine for the rst time after replacing the batteries, the
pattern memory will be scrambled and the machine may behave strangely until you
do a factory reset. To do so, power on the TR-707 while holding down the TRACK and
PATTERN GROUP A buttons.
14.
If the bank selection system appears to be functioning, but the sounds themselves are
playing back with digital distortion, or are scrambled, it is very likely that there is something
wrong with the connections between the expansion board and the IC35 socket. Check that
it is seated properly in the socket, and check for any solder bridges, dry joints, damaged
tracks or pads where you soldered the socket.
If the sounds are playing normally but the bank selection is not working as intended, check
the connections from the ribbon cable to the panel board. Check that the wires are tted in
the correct sequence and are connected to the right locations.
If the machine crashes at startup, you probably have a short between two or more of the
locations where wires 1-8 connect to the panel board, as these are the TR-707’s data bus.
Otherwise, check that no wires are getting pinched in the case or by screws, and also that
the various connectors inside the machine have been reconnected – especially the two that
join the top case and panel board to the main board, it happens to the best of us! :-)
Troubleshooting
