
8712ET/ES and 8714ET/ES Troubleshooting and Block Diagrams
RF Network Analyzers Category 1 Failures: Dead or No Display
Service Guide 4-15
15 CPU Support
Circuitry
Errors: Stuck interrupt.
Tests interrupt circuitry.
Replace CPU board, or check U106, U109, and U110.
16 Analog Bus Errors:
CPU +5 V supply is out of range!
Vpp Flash Supply is out of range!
Tests analog bus ADC on CPU board.
Replace CPU board; check power supplies, or check U300,
U338, and Q300 voltage regulator chips for Vpp. Also check
the analog bus ADC chips U223, U222, and VR201.
17 Real Time Clock Tests ability to write/read to real time clock.
18 Front Panel Interface Errors:
Front panel keyboard FAILED.
Command write timeout.
Read input timeout.
Clear input buffer failed.
Echo byte test failed.
Tests front panel control processor. Replace CPU board or
check U510, U511 and U507.
19 Floppy Disk
Controller
Error:
Floppy Disk controller FAILED.
Error number <num>
Tests controller chip, accesses registers, writes commands,
and verifies response.
Replace CPU board or check U607, U603, U604, and U606.
20 GPIB Interface Error: GPIB test FAILED.
Data bit error on these bits: (followed by list)
Tests GPIB interface, writes to chip and verifies response.
Test not performed if anything connected to GPIB. Replace
CPU board or check U524-U526.
21 RS-232 Interface Errors:
RS-232 interface test FAILED.
Bus error.
Cannot access.
Data bit error on these bits: (followed by list)
Tests RS-232 portion of the Super I/O chip, accesses registers
on chip, and checks for clock input.
Replace CPU board or check Super I/O chip, U607, or its
clock, U606.
Test Test Name Applicable Error Messages and Notes
Note: Tests numbered: 8, 11, and 14−17 are not run during power-up.
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