Section 4
TM9340-G-00
15 August, 2019
4-1
4. OPERATION AND MAINTENANCE
4.1.
OPERATION
The Model 9340 series of decade boxes are calibrated at the front panel red and black
binding posts. The accuracy specification is determined as the resistance value offset
from the zero selection resistance value.
Above 1 k
selection the zero resistance value is negligible. Below the 1 k
selection
the zero resistance value of the decade box needs to be taken into consideration to effect
the specified accuracy.
The green binding post case ground terminal may be used to reduce susceptibility to
electromagnetic and electrostatic influences.
4.2.
MAINTENANCE AND CALIBRATION
The Model 9340 series of decade boxes require minimal maintenance other than periodic
calibration and ensuring the front panel terminals are clean. Cleaning may be
accomplished by wiping with ISO-propanol and allowing to dry over a 12 hour period
before use.
Calibration should be performed using a 6½ Digital Multimeter with a minimum
accuracy specification of better than ±20 ppm over the range of 1
to 10 M
. A
suitably accurate Teraohometer is required for models with resistance ranges above 1
G
.
4.3.
REPAIR
Although the Model 9340 series has been designed to operate for may years without the
need of repairs, circumstances beyond the control of the manufacturer may require
replacement of specific resistor elements or entire decade switch assemblies.
The screws in the top panel may be removed to allow access to the switching circuitry by
carefully lifting the top panel assembly out of the bottom portion of the enclosure.
Careful soldering so as not to overheat the switch terminals is required when replacing
specific resistance elements. It is recommended that the defective resistance elements be
cut out of the circuit and that the replacement element be attached to a short portion of
the element lead left in contact with the switch terminals. This method will reduce any
effects from applying heat to the circuit elements.
It is recommended that the decade box be returned to Guildline Instruments if it should
be necessary to replace an entire decade switch.
