E8257D/67D, E8663D PSG Signal Generators Service Guide
Troubleshooting
Troubleshooting Assembly–Level Problems
1-57
• If the +1.9 VD supply voltage is bad on the A31 Motherboard, check the +3.4 VD supply at the A19 Power Supply.
— If the +3.4 VD supply is good at the A19 Power Supply, replace the A31 Motherboard.
— If the +3.4 VD supply is bad at the A19 Power Supply, troubleshoot A19 Power supply.
1601 Apps 1 <–> Apps 2 Comm
• If the +1.8 VD supply voltage is good on the A31 Motherboard, replace the A14 Baseband Generator
• If the +1.8 VD supply voltage is bad on the A31 Motherboard, check the +2.6 VD supply at the A19 Power Supply.
— If the +2.6 VD supply is good at the A19 Power Supply, then replace the A31 Motherboard.
— If the +2.6 VD supply is bad at the A19 Power Supply, then troubleshoot the A19 Power supply.
1602 Apps 1 <–> SH4 Comm
• Replace the A14 Baseband Generator
1603 Apps 2 <–> SH4 Comm
• Replace the A14 Baseband Generator
1604 FLiegan <–> Apps 2 Comm
• Replace the A14 Baseband Generator
1605 SRAM Test
• Replace the A14 Baseband Generator
1606 SDRAM Test
• Replace the A14 Baseband Generator
1607 Paren <–> SH4 Comm
• Replace the A14 Baseband Generator
1608 VCO Tune Test
• If the +32 V, ±15V, –5.2 V2, and + 5.2V supply voltages are good on the motherboard, use an oscilloscope to check
the 10 MHz signal on the A31 Motherboard at P161 pins 26 and 91. The signal should have a period of 100 ns
with an amplitude greater than 0.4 Vpp.
— If the 10 MHz signal is good, replace the A14 Baseband Generator.
— If the 10 MHz signal is bad, check it at the A7 Reference.
• If the 10 MHz signal is bad at the A7 Reference, refer to A7 Reference troubleshooting.
• If the 10 MHz signal is good at the A7 Reference, replace the A31 Motherboard.
• If the +32 V, ± 15 V, and +5.2 V supply voltages are bad on the motherboard, check the origin of the supply.
— If the supply voltage is good at the origin, replace the A31 Motherboard.
— If the supply voltage is bad at the origin, troubleshoot the A19 Power Supply.
• If the –5.2 V2 supply voltage is bad on the motherboard, check the –7 V supply voltage at the A19 Power Supply.
— If the –7 V supply voltage is good at the A19 Power Supply, replace the A31 Motherboard.
— If the –7 V supply voltage is bad at the A19 Power Supply, troubleshoot the A19 Power supply.
1609 IQ DAC Output
• Replace the A14 Baseband Generator
1610 PLL Test
• Replace the A14 Baseband Generator
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