Teledyne API Model 200AH NOX Analyzer Instruction Manual, 06492, Rev. G2
8-14
8.8. Prom Replacement Procedure Preparation: If any setup changes such as RANGE, AUTOCAL, ON/OFF etc. have been made,
record the changes because all settings should be checked after the PROM is changed. See
Figure 9-2 for location of prom on CPU card.
1. Turn the machine off.
NOTE
The PROM is static sensitive, be sure that you are properly
grounded before handling any of the electronics.
2. Remove the hold down screw that holds in the V/F-CPU assembly to the motherboard.
Disconnect the J9 power connector from the motherboard. Gently lift the assembly far
enough out of the instrument to remove the connector to the display and the RS-232
connector.
3. Locate the CPU board, which is attached to the larger V/F board.
4. Remove the CPU-V/F board assy, laying it down on an insulating surface such that the board
edge pins on the PCB are on the left. The PROM chip will be at the top center. See
Figure 9-2 for prom location. Gently pry the chip from its socket and replace it with the new
chip. Install the chip in the left end of the socket with the notch facing to the right. Make sure
that all of the legs insert into the socket correctly.
5. Re-attach the CPU board to the V/F board, re-connect the RS-232 and front panel display
cables, and then re-attach the assembly to the motherboard.
6. Turn the M200AH ON and observe the front panel display. As the machine goes through the
setup the version number will be displayed on the front panel. It should read the same as the
version number printed on the prom.
7. Check and re-enter if necessary any non-default settings such as RANGE or AUTOCAL. Re-
enter the SPAN value. Check all settings to make sure that expected setup parameters are
present.
8. Re-calibrate the machine so that the default slope and intercept are overwritten with the
correct values.