Fluke 5500A, Service Manual

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5500A
Service Manual
4-10
1040 (DDE:FR ) A5 interface fault
Is the A5 assembly installed? If so, suspect circuitry includes A5 digital ICs U14, U12,
or CMOS switch U7, relay K15, and driver IC U15.
1041 (DDE:FR ) A5 X1 input amp fault
Suspect ICs on the A5 assembly include U34, U20, U8, U7, Q4, and Q3, as well as the
+17, and -17 V supplies and their associated circuitry.
1042 (DDE:FR ) A5 lo comp amp fault
Suspect ICs on the A5 assembly include U3, U37, U4, U5, and U7.
1043 (DDE:FR ) A5 coarse ZDAC fault
Suspect ICs on the A5 assembly include U25, U1, U24, U39, and U4.
1044 (DDE:FR ) A5 fine ZDAC fault
Suspect ICs on the A5 assembly include U22, or U23, and U4.
1045 (DDE:FR ) A5 inverting amp fault
Suspect ICs on the A5 assembly include U24, U1, and relay K16 (and respective relay
driver U30).
1046 (DDE:FR ) A5 X2.45 input amp fault
Suspect ICs on the A5 assembly include U20, Q3, Q4, and noninverting amp U34 in
X2.45 gain mode, as well as U3, and U10.
1047 (DDE:FR ) A5 X3 input amp fault
Suspect ICs on the A5 assembly include U20, Q3, Q4, and noninverting amp U34 in
X3.08 gain.
1048 (DDE:FR ) A5 X13.1 input amp fault
Suspect ICs on the A5 assembly include U20, Q3, Q4, and noninverting amp U34 in
X13.1 gain mode.
1049 (DDE:FR ) A5 input leakage fault
Suspect ICs on the A5 assembly include Q3, Q4, U34, and analog MUXs U26, U27, and
U29.
1050 (DDE:FR ) A5 offset comp fault
Suspect components on the A5 assembly are IC U4 and resistor R17.
1051 (DDE:FR ) A5 input voltage detect fault
On the A5 assembly, suspect circuits are the +/- 17 V supplies (Zener diodes VR4 and
VR3 may be regulating too low but may be withing tolerance). Suspect ICs are U16 and
U5. Check the voltage threshold levels on U16.