Tek 2465B DMM Test failure

[SteveRosenlund]

Hello,

On my Tek 2465B DMM, i'm getting an error on startup regarding the DMM.  The error is "DM Test 76 Fail 01".  This means that most likely one of the two fuses on the DMM has opened.  One is external and one is internal.  Do any of you know where the internal fuse is?

From the service manual: DMM FUSES

The DMM has two fuses, in series with the HI input
connector, to protect the DMM circuitry from current over-
load. One of the fuses is on the DMM front panel and the
other is inside the instrument cabinet. Only the front-panel
fuse is operator replaceable; if the internal fuse opens,
refer the instrument for fuse replacement or repair to a
qualified service technician.



If the DMM does not make measurements after a
potential current overload condition has occurred, turn off
the instrument, remove the probes, and check the front-
panel fuse. If it has opened, replace it with a fuse of the
same type and rating. Otherwise replace the fuse in its
holder and turn on the instrument. If the internal fuse has
opened, the message DM TEST 76 FAIL 01 will appear on
the crt readout during instrument power-up. In this case,
refer the instrument to a qualified service technician for
repair.

[med6753]

I have a 2465 with the DMM and according to that manual a Test 76 Fail 01 is defined as "Malfunction of DMM, or if this is the only failure, V/F Input Multiplexer U5020 input, pin 2".  So apparently there have been changes/updates with the 2465B.

Anyway, the 2nd fuse right there on the front of the DMM board. 

[SteveRosenlund]

I fixed the issue. Turned out to be just a loose ribbon cable from the dmm board.