Specifications

7
Installation with a DSP Daughterboard
1) Skip this step if Eprom U7 on the DSP daughterboard is ver. 7.3. If Eprom U7 is ver. 7.2 or lower,
locate and remove U7.
2) Use an IC removal tool if you have one. If not, slide the flat blade of the screwdriver under one end
of the chip and elevate carefully. Do the same thing at the other end of the IC and it will pop out
cleanly. BE SURE the screwdriver is between the IC and the chip socket, NOT between the chip
socket and the board.
3) Install the new 32 pin eprom in the U7 socket on the DSP daughterboard. Be very careful to orient
the notch in the end of the chip to match the notch in the outline on the circuit board. Make sure all
pins are straight and fit direcltly into the Eprom socket before you carefully press the new eprom
into the socket. All pins should be inserted directly into the socket with no pins curled under the chip
or bent outside the socket.
4) Follow the next steps to remove components from the main PC board.
5) Locate and remove C40 near J1 (see figure B).
We recommend that you remove the capacitors and resistors by desoldering them from the back of
the board. Remove the solder from the holes with a solder sucker tool or solder wick. Use care not
to overheat the board. You may burn the board or damage the pad or barrel in the hole. When hole
and the lead are clear of solder, gently remove the component from the top of the board. In some
cases, it may be easier to remove the component by clipping the leads of the component close to the
body of the component before desoldering it.. Then while holding the lead with the needle nose
pliers, CAREFULLY heat the solder just until the lead can be removed without force. Be very
careful not to pull the barrel from the board by pulling before the solder flows. DO NOT OVER-
HEAT. The hole can then be cleaned with a solder sucker tool or solder wick.
You will also need to clean the solder from the C40 pads. Observe the same precautions as above
and do not overheat the board.
6) Locate and remove the wire on the pad on the DSP daughterboard labeled “C89 Rear”. Remove the
other end of the wire from the rear pad of C89 on the PK-900 main board. Discard the the removed
wire.
You will also need to clean the solder from the C89 rear pad and the daughterboard pad labeled
“C89 Rear” Observe the same precautions as above and do not overheat the board.
7) Remove R253, if it is installed on your PK-900. See Figure A.
You will also need to clean the solder from the R253 pads. Observe the same precautions as above
and do not overheat the board.
8) Re-install the main board on the chassis using the screws you saved when you removed it.
9) Reconnect the front panel connectors to the main board.