REV DEC 1986 6-35
4. If the Phase Clock Array is working, the problem is the Time Base. See the Time Base
troubleshooting chart located in the "Diagrams" section of this manual.
2. If no outputs, the problem is probably U470 or the input circuit to U470 at pins 65 and 67; Le.,
CR580, C580, or C462.
3. If U470 is replaced and outputs are obtained, do the following test: turn the 2430 to the setting 5
ns/div, REPET ON, NORMAL acquisition. Insert a 30 MHz sine-wave into CH 1. Watch the waveform
as it is created on screen. Make sure no misplaced samples occur 20 ns after they should (this will
be
obvious by the appearance of spikes on the screen within about one minute). If this happens,
replace gate array again until the problem goes away.
1. Check A1OU470(Phase Clock Array) at pins 13, 14, 15, and 16 for output clocks.
NO SIGNAL Phase Clock Array Outputs A1OU470(schematic diagram 11)
ACQUISITIONS
4 OPERATIONALPROBLEMS(Not detectable by diagnostics)
1. If aUthe power-on tests pass, go to Procedure 4. If not. then go to Procedure 7.
NOTE: THIS IS NOT SELECTABLE, IT EXECUTES AT POWER-ON.
POWER-ONDIAGNOSTICS
3
If the menus are normal (can focus, adjust intensity, etc.), then go to Procedure 3.
If there are no displays then go to Procedure 5.
If there is a display, but the display is incorrect (no intensity control, out of focus, etc.), a dot only,
a vertical or horizontal streak, then it is an analog problem. Go to Procedure 6.
If portions of the readout are missing or wrapped over, but the power-on test runs, the front-panel
controls and the EXT DIAG menus may still be useful. Attempt to use the diagnostics to determine
the failed tests. Also, read the binary code of the first failed test that is flashed by the Trigger
LEDS during the power-on sequence. Use that information as a starting point for troubleshooting,
using the steps indicated for the failed test in Procedure 7, "EXTENDED DIAGNOSTICS". The
most probable cause of a failure of this type is a bus problem or bad IC on a bus causing a stuck
bit in Display circuitry of the Time Base/Display board (schematic diagrams 16 and 17). The
busses to suspect are the ones connected to the IC indicated by the failed test.
CRTDISPLAYCHECK
Are TRIGGER LEDs flashing? If all lights are flashing, suspect Waveform /-LPROM U480 or U490
(diagram 2) or their selects.
Is there activity from GPIB LEDs during turn-on? If the three LEDs above the 2430 crt (LOCK,
SRQ, and ADDR) all light then go through a binary counting pattern (test number 2170), the diag-
nostics are working, and the instrument is alive. Go to Procedure 2.
After 30 seconds of turn-on, press MENU OFF and cycle the SLOPE switch. If the + and -
Slope LEDs light alternately, the System J.l.Pis alive, and the operating system is active. Go to
Procedure 2.
Did the attenuator relays click? If the relays clicked, the power-on self tests were running.
If any of the signs-of-life occurred, then assume that there is some "life in the box" and go to Pro-
cedure 2; otherwise, go to Procedure 8.
TESTS FOR
1.
LIFE
2.
3.
4.
5.
2
1.
2.
3.
4.
INITIAL INDICATIONS
Table 6-6
2430 Troubleshooting Procedures
Maintenance-2430 Service
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