Triplett 3444 Tube Tester from NASA Johnson Space Center
The meter and the tube chart now have LED bulbs installed.
The electrolytic capacitors have been changed and upgraded.
A new modern bridge rectifier replaces the old tubular bridge rectifier.
The original keys for the lock on the case are included.
The 3444 was calibrated by NASA and is still calibrated.
Included is the verification that this was purchased from NASA.
Serial Number 8250
The serial number is important and refers to this being a later model with all the upgrades that include (above 2000) the center pin of the loctal socket connected to pin 9 of the 9-pin miniature socket for use with the CG Adapter, (above 3000) has the nuvistor socket in the panel and a cathode cap jack, and above 5000 have bias voltage applied to both control grids of all dual section tubes such as the 12AX7.
Tests Most Old and New Tubes and Nuvistors
Tests for Mutual Conductance (Gm), Noise, Shorts, Leakage, Plate Current, and Life Test
Capable of Testing to Tube Manufacturer's Voltages
Filtered Plate and Screen Voltages to 250 VDC and Bias to -50 VDC
Tests Both sections of Dual Section Tubes Without Resetting Selectors
Noise Tests Jacks
Measures Plate Current up to 50 Milliamps on Main Meter
Measures Gm up to 30,000 Micromhos
Gm Check Self-Calibration Feature
Illuminated Main Meter and Roll Chart with LED Bulbs
Includes a DVD with the manual, tube data, and calibration information.
Includes a plate cap and grip cap connectors.
I did find an error on the tube data chart currently on the tube tester in regards to the 6L6. I corrected the error on the tube chart after verifying the correct information. The bias setting on the current tube chart called for 14, but should be 18 as it calls for on other tube charts and in the actual manual for this 3444 (see the last pictures). When testing a 6L6 using 14 for the bias the Gm was over 6000. The 6L6 being tested usually tests 500 over the NOS average value, or what Triplett calls a bogie value. At the correct bias setting of 18, the 6L6 tested at 5200 for Gm. The Bogie value per the Triplett chart is 4700. So the Gm results matched perfectly. A 12AX7, both triodes tested in the pictures, had the same perfect Gm test results, as well as a 6AQ5 as compared to Triplett bogie values.
This 3444 was more than likely in use at NASA at the time of the Apollo missions. “Houston We Have A Problem”
The socket savers all worked with no issues as did the plate current reading, gas, shorts and leakage.
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Triplett 3444 Tube Tester from NASA Johnson Space Center
Bought directly from NASA in 2021.