Tube Tester Service Upgrades

The following upgrades are available for many Hickok tube testers sent in for repair/calibration. Not all upgrades are available for all tester models. Please contact me to find out which options apply to your tester or if desired upgrades are available for your tester.

Hickok Upgrades (PDF)

The upgrade features I provide are for improving the performance of older testers. To allow for more accurate testing results, reliability, and for providing improved features to allow the user to perform additional tests not available on his model at the time!

SS-83 Solid State Rectifier

This replaces the 83 mercury vapor tube! This eliminates the hazardous material issue and reduces the typical problem of calibration drift in the tester. The 83 tube is the first and primarily the main cause of out of calibration and drift in the tester.
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SS-5Y3 Solid State Rectifier

Replaces 5Y3 tube! This tube is the second cause for out of calibration conditions in the tester!
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Digital Meters

Digital meters are important to improve the measurement accuracy of the tester. They are more accurate than the old analog meters and many of the old meters are further out of specification accuracy due to aging of the meters parts. These meters are designed to mount into the tester's rear compartment as additional meters.
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Higher Current 6.3 Volt Filament Transformer

This is useful for testing 6.3 volt heater tubes which require up to 4 amps of heater current. It also will allow for a lower load on the main transformer in the tester.

Precision Calibration

This calibration includes installing precision resistors and trim controls to allow for improving the measurement accuracy of the tester! The improvement is typically from the standard +/- 10% to 12% to that of +/- 5% to 7% This is a Labor charge which includes all the required parts to improve the calibration.

Tight Calibration and Calibration Trim Controls

This improves the calibration and also allows for the trimming of key calibration items rather than selectively installing a resistor close enough to the required value based on standard resistor values which is the standard calibration method. The tighter calibration is about +/- 8% to 9% rather than the +/- 10 to 12% of the original factory calibration value. This is a Labor charge which includes all the required parts to improve the calibration.

Calibration for using a Variac (Auto-Transformer) to control the AC Line Set Voltage

This is where the unit will be calibrated for allowing the customer to use a variac to adjust the line set on the tester. This greatly reduces the large line sag voltage that reduces the accuracy of the mutual conductance Gm measurement. Testers which have a separate line set meter like the 539A, 539B, and 539C already have improved capability because the ac line can be set separately and at the actual test load. The use of the variac provides even better accuracy over the adjustable resistor used in these testers which is in series with the primary of the power transformer.

Addition of Bias Fuse Lamp Protection for units without Bias Fuse

Early Hickok units did not have a bias pot protection circuit. If an error is made in testing a bad tube there is a good possibility to burn out the bias control which are no longer available. This upgrade installs this devise as a circuit protection and it can be installed on the top panel, or inside the tester.

Standard Reference Tube

This is a 6L6 reference tube that is burned in and then tested to laboratory standards. The tube comes with a manual containing detailed data charts for use in checking, or calibrating most any tube tester. All data for accurately testing Hickok testers are provided. Data for most other makes and models are also in the manual. In addition the tube test results are compared to the tube manual (tube specification data sheet).
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Custom Upgrades

If you have specific requirements contact me for a price quote to develop an upgrade for your needs!
See some examples