Fluke 2625A User Manual

Service Manual

5-18

A3R11 HI

Input

A3K1 through A3K14, A3U4, A3U5, A3U11, A3U12
A3L1, A3L2, A3L3

A3Z3 pin 1

Input

A3R11, A3C31, A3K15

A3U6 pin 13

Amplified (X 2.5) input

A3U7, A3Z3, A3Q3 through A3Q9, A3C15, A3C16,

A3R24, A3A25, A3R26, A3R27, A3R28, A3C23,
A3U6, A3Q13, A3U8

A3Z1 pin 2

DC equivalent of original input

A3Z1, A3U8, A3R20, A3C6, A3C7, A3C10, A3R16,
A3R17

A3U8 pin 61

DC equivalent of original input

A3Z1, A3U8, A3R20, A3C6, A3C7, A3C10, A3R16,
A3R17

Setup a channel with an open input for the desired ohms range and place the instrument
in monitor mode on that channel. Use a meter with high input impedance to measure the
open-circuit voltage at the channel input for the ohms range as listed in Table 5-6. If a
high input impedance meter is not available, only the 30-k

Ω

 and lower ranges can be

checked.

300

Ω

3 k

Ω

30 k

Ω

300 k

Ω

3 M

Ω

10 M

Ω

3V
1.3V
1.3V
3V
3V
3V

If the proper voltage is not measured, setup a channel on the 300

Ω

 range (open input),

and have the instrument monitor that channel. Check for 3V dc with respect to A3TP9,
and work through the HI SOURCE and HI SENSE paths as described in Table 5-7.

If the HI path works correctly, trace continuity through the LO path. Check among A3L4
through A3L24, A3K1 through A3K14, A3R35, A3U8 pin 11, A3R43, A3K16, A3R34,
and A3U8 pin 13.

A3U8 pin 14

Ohms Source

A3U8

A3R10 HI SRC

Ohms Source

A3R10, A3K16, A3RT1, A3Z4, A3Q10

Channel HI

Ohms Source

A3K1 through A3K14, A3U4, A3U5, A3U11, A3U12, A3L1,
A3L2, A3L3

A3U8 pin 23

Ohms Source

A3R11, A3K17, A3R42, A3C32

A3U8 pin 58

Ohms Source filter output

A3U8, A3Q2