Rap 12: High-Speed Modem Test Failure - OKIDATA OF1000 Service Manual

RAP 12: High-Speed Modem Test Failure

START
Place the leads of your multimeter across the RJ-11C data terminals, TIP and RING (you will be
measuring rms voltage).
Perform the H-MODEM SEND TEST (transmitter) and the H-MODEM RECEIVE TEST (receiver).
NOTE:
You will need two Okifaxes to perform this procedure. However, they need not be at the same
location.
Are you troubleshooting the transmitting Okifax?
NO Go to POINT - A
YES Does the multimeter read approximately .27 volts rms?
YES Although the Okifax 1000 appears to be transmitting, the validity of the data transfer
cannot be assured by this voltage measurement. If you are encountering communication
error, replace the following in the order listed.
NO Place the leads of your multimeter across CN7 pins 1 and 4 of the NCU board.
Does the multimeter read approximately .27 volts rms?
YES Replace the NCU-U board.
Is the problem resolved?
YES End of procedure.
NO Replace the MCNT-150 board.
NO Is + 12 vdc present on CN1 pin 14 of the MCNT-150
board and is - 12 vdc present on CN1 pin 15 of the MCNT-15 board?
Is the problem resolved?
(1) MCNT-150 board
(2) NCU-U board
(3) LINE-JU board
NO Replace the PWU-150.
Service Guide OF1000
Chapter 4 Failure & Repair Analysis
Page: 143