Substantially improve the performance of your instrument: Pre 1993 Model 306's and 307's with the serial numbers listed below can be upgraded to final production standards* for a modest price.

Performance Upgrade Package benefits include:

° Probe restrictions are removed (use any combination of probes)§.
° Eliminates all internal adjustments. Annual performance verification becomes a closed case procedure requiring no adjustments.
° Improves basic accuracy to better than 1%.
° Improves measurement technique to true RMS based rather than average based.
° Improved readout stability in all modes.
° Test current bar graph range extended from 40 Amps to beyond 50 Amps.
° Specified lower limit for the test current range is improved from 5 Amps to 2.5 Amps.
° Fresh NIST / MIL-STD-45662A performance verification certificate with test data and instrument date sticker included.

* The upgrade does not affect your instrument's test current duty cycle specifications (early instruments had lower duty cycle limits than final production instruments). For very early instruments with the round monolithic probe connector structure, the probe connection system is not modified to the current square modular connection style, but the probe heads or cables will be upgraded or replaced depending upon condition. Safety certification listing status is not altered. For Model 307 owners whose instrument was upgraded from a Model 306, the larger main digital readout is not replaced by the flush mounted type (used in instruments originally ordered as Model 307s).

Briefly, the Performance Upgrade Package consists of the following work:

The entire main circuit board assembly is replaced with a new, final design circuit board assembly. A new internal current sense resistor assembly is installed, replacing the probe head mounted current sense resistor assembly. The digital panel meter, 5V power converter (Model 307) and sense connector board are modified to the final electrical design. A front panel information revisions label is attached to the top of the cabinet. The Model 100 probe is modified to the current Model 105 design. Dielectric withstand and ground integrity tests are performed. The performance verification procedure is performed. Support documents are generated, including a new NIST / MIL-STD-45662A performance verification certificate with test data and instrument date sticker. The original one year warranty is renewed.

Upgrade Prices:

Model 306: $125
Model 307: $150

Review our rigorously strict credit terms before ordering.

20 December 2005**: The following serial numbers have not yet been upgraded (leading zeros removed). Red text indicates a Model 307, all others are Model 306's: 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 18, 19, 20, 21, 22, 23, 24, 25, 26, 29, 30, 32, 33, 34, 35, 36, 38, 42, 43, 44, 45, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 66, 67, 68, 75, 77, 79, 80, 81, 83, 84, 87, 93, 95, 100, 104, 106, 107, 110, 111, 112, 113, 115, 116, 118, 119, 122, 123, 124, 126, 127, 128, 131, 137

19 Upgrade kits remain in our inventory. Upgrades will become unavailable when these kits are exhausted.

**The serial number list above is always up to date. The indicated date represents the last date the list was changed.

§Note: Serial numbers 4 through 34, but excluding 27, use an obsolete monolithic probe structure with round connectors. The Performance Upgrade Package does not include an update of the probe connection system for these instruments. However, the probe heads or cables will be upgraded or replaced depending upon condition.

Transit packing instructions

Include the Model 100 probe with your instrument as it must be modified.

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78 Instruments total not yet upgraded as of 18 February 2001