E8257D/67D, E8663D PSG Signal Generators Service Guide
Troubleshooting
Troubleshooting Assembly–Level Problems
1-14
Symptom: RPG not working properly
1. Ensure that the front panel green power on LED is on. If it is not on, refer to “Power Supply Troubleshooting” on
page 1- 14.
2. Check the front panel operation by checking random hardkey operation.
3. Check P13–12 for +5.2 Vdc. If the voltage is not present, refer to “Power Supply Troubleshooting” on page 1- 14 for
troubleshooting.
4. Press the Frequency hardkey on the front panel.
5. Using an oscilloscope, monitor P13–14 and P13–10 while rotating the RPG knob. The LCD frequency value should
change, and both signals at P13 should pulse to a TTL high. If either signal does not pulse, replace the
A1 Keyboard.
6. If the signals pulse at P13, check the signal at P221 pins 57 and 17 of the motherboard. If the signals pulse at
P221, replace the CPU board.
Symptom: Screen saver not working properly
The screen saver delay can be set for any integer from 1 to 12 hours. The CPU board controls the screen saver by
pulling the LIGHT_EN line low.
1. If the delay time elapses and the display does not go dark, check the LIGHT_EN signal at P12–3.
• If the signal is a TTL low, replace the dc to ac inverter.
2. If the signal is a TTL high, check it at P221–16 of the motherboard.
• If the signal is high at P221, replace the CPU board.
Power Supply Troubleshooting
The power supply is a switching supply with automatic line–voltage and frequency selection. Because of this, a switch
is not required to set 115 VAC or 240 VAC operation. The input power line is fused, but the fuse is not replaceable; if
the fuse opens, you must replace the power supply.
NOTE For the E8267D, if the red PS–FAULT LED is off (see Figure 1- 5), troubleshoot the power supply.
WARNING After unplugging the instrument, wait 30 seconds to allow the supplies to discharge before removing
or installing an assembly.
Tables 1- 5 through 1- 7 list the motherboard test points (connector and pin number) and power supply voltages for the
E8257D. See Figure 1- 2 on page 21 for connector locations.
Tables 1- 8 through 1- 12 list the motherboard test points (connector and pin number) and power supply voltages for
the E8267D, beginning on page 1- 17. See Figure 1- 3 on page 22 for connector locations.
Table 1-5 E8257D/E8663D Power Supply vs. Assembly Matrix (1 of 3)
Motherboard test points: +32 Vdc +15 Vdc +10 Vdc +8 Vdc +9 Vdc +5.2 Vdc
A1 Keyboard P13–12
A2 Display P11–44
A3 Power Supply P231–1, 41 P231–3, 4,
43, 44
P231–6, 7, 46,
47
P231–15, 16,
18, 19, 55, 56,
58, 59
A5 Sampler P22–7 P22–6, 21 P22–20, 5 P22–14, 29
A6 Frac–N P32–7 P32–6, 21 P32–20, 5 P32–14, 29
A7 Reference P42–7 P42–6, 21 P42–20, 5 P42–14, 29
A8 Output P52–7 P52–6, 21 P52–20, 5 P52–14, 29
A9 YIG Driver P112–6 P112–5, 30 P112–15, 16,
40
P112–17, 18,
42
P112–3, 28
To Next Page
Loading...