Videotek TVM-821D, Руководство по эксплуатации и инструкции, Страница: 25 / 29

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Troubleshooting Procedure
Unit appears to be dead (no LEDs on, graticule lights off, and no
CRT display)
. Ensure power switch on front of unit is in the “I”
position.
1. Make sure power source to unit is live.
2. Check that power cord is firmly seated into rear of unit
3. Check external fuse. If blown replace with fuse of same type.
4. Check low voltage power supply. The fuse on this supply has
been bypassed to ensure only the fuse on the outside of the unit
will need to be replaced.
a. Check that AC switch on front panel is allowing AC to the
low voltage power supply.
b. Check for +5V, ± 12V from this supply
c. Disconnect the three DC power cables from the supply.
d. Recheck the +5V, ± 12V from this supply. If one or more of
the voltage from this supply are missing with no load, the
power supply is damaged.
i. Reconnect each of the power cables one at a time.
Connect the power to the TVM-850 board first, the
TVM-851 board next, and the power cable to the high
voltage block last. As each is reconnected, monitor the
+5V, ± 12V from the supplies.
ii. If one of the cables causes the loss of a voltage, the
board or high voltage block may be damaged.
Front LEDs on, no CRT display. Make sure intensity is not turned
down.
1. Press CAL button. If vector centering dot appears in middle of
CRT, use the H. POS. and V. POS. knobs to return calibration
waveform to its proper position on screen.
2. Make sure that low voltage supply 12V output is operating pro-
perly.
3. WITH UNIT OFF, ensure that all cables inside the unit between
the boards are properly connected. Ensure that CRT anode cap
is on the tube and that the tube wiring harness is properly con-
nected.
4. Test points on the TVM-850 board can be used to monitor the
waveform and vector analog outputs. The signals may be traced
through the TVM-851 board.
IT IS NOT RECOMMENDED THAT
THE TVM-852 BOARD BE PROBED AS HIGH VOLTAGES
(>2000V) ARE PRESENT ON THIS PCB!
5. High voltage power supply may be damaged.
CRT display on, no LEDs. Cycle power to unit.
1. A CPU cold start can be executed by holding the CAL button
while power is applied to unit.
Note: cold starting a unit will clear the user memories.
2. Ensure that all cables are connected to the front panel PCB
(TVM-853). This board uses on +5V to operate. It communi-
cates to the TVM-850 board’s micro via a 16 pin ribbon cable.
Check that the socketed ICs on the TVM-850 board are firmly
seated in their sockets.
Serial input connected to INPUT A and or INPUT B, but CRT
display only flat lines.
Ensure that the proper input is selected on the front panel.
1. If data error light is flashing and the EQ lights for the selected in-
put are at maximum:
a. Check to ensure the cable BNC at the rear of the unit is pro-
perly connected to one of the serial inputs.
i. Check that the signal generation equipment is powered
on and connected correctly.
ii. Ensure that the looping input is properly terminated at
the end of the cable.
b. If data error light is flashing and the EQ lights for the select-
ed input are not at maximum.
i. Check to ensure that digital data is 601 video. This
scope will only display 601 serial component data
(525/625).
ii. Source of 601 data is providing data which may be
missing proper timing signals.
c. If a known valid input signal is applied to an input, but only
flat lines are displayed, check the input sections of the TVM-
850 board.
CRT display is rolling.
1. If external reference in ON and if both 525 and 625 reference
LEDs are OFF:
a. Make sure that external analog reference is applied to refer-
ence input on at rear of unit.
b. Make sure that external analog reference is properly termi-
nated at the end of the cable.
c. Ensure that the minicoax cables are properly connected to
the TVM-851 board.
d. Check that the analog reference is genlocked to the input
signal(s).
2. If external reference is OFF and if both 525 and 625 reference
LEDs are OFF:
a. Ensure that input data is 601 serial component data (-
525/626).
b. Check the input section for the selected input on the TVM-
850 board.
3. If viewing two inputs (A and B), the unit will always sync on
INPUT A, the B input can roll if not genlocked with the A input.
CRT display is not starting at beginning of screen.
1. Adjust horizontal position control knob.
2. If external reference in ON and if both 525 and 625 reference
LEDs are OFF:
a. Make sure that external analog reference is applied to refer-
ence input on at rear of unit.
b. Make sure that external analog reference is properly termi-
nated at the end of the cable.
c. Check that the analog reference is genlocked to the input
signal(s).
3. Unit may simply be showing the timing difference between the
serial data and the analog reference.
4. If INPUT A and INPUT B are selected, the CRT will use the A in-
put as the reference (external reference OFF). The B input will
be display the timing difference between the two inputs.
5. Unit may need to be calibrated.
6. High voltage power supply (100V) may be damaged.