Martel Electronics 135 - Manual (Page 64)

Fuse Testing
The calibrator employs fuses to protect the outputs and inputs in the
event the calibrator is improperly connected to external circuitry. It is
necessary to remove the covers in order to access the fuse panel. The
following tests should be performed BEFORE removing the covers to
determine if a fuse is actually blown.
Service Information
130/135 60
Fuse Type/
Location
Fuse
No.
Function Test
Input/
Output
Top PCB
130/135 F1 mA Input Connect an ohmmeter across the
input milliamps terminals. The
resistance should be approximately
5 ohms. If it reads open, the fuse is
probably blown. If it reads
significantly higher than 5 ohms, the
input dropping resistor may have
been damaged due to an overload.
Model 130
Model 135 F4
F2
Freq
Output
Check for normal operation on the
Volts output 10V scale. If this is
normal, but there is no output Freq
mode on the frequency terminals,
the fuse may be blown.