The Hickok 539B is considered one of the finest mutual conductance tube testers ever made. I restored and upgraded this tester for accuracy and long-term reliability. A true workhorse for any serious tube collector or technician. This is a perfect tube tester for tube matching – Gm and plate current.
Key Features:
- New Gm meter – Replaced failed original for more precise, reliable readings
- Updated roll chart – 1970 edition for expanded tube coverage
- New anode lead – For grid and plate tube connections connections
- Solid-state rectifiers – Replaced tube rectifiers for improved stability and reduced transformer loading
- Bias circuit protection – Bias fuse lamp added to guard against Bias circuit damage
- Plate current mod – Easily read plate current using external voltmeter; there is no need to use a milliamp meter
- Transformer balanced – Optimized for consistent operation and accurate test results
Condition:
There are NASA and “Government Property” stickers on the deck. I lightly cleaned and restored the case and it is in exceptional condition. There are a few scuffs as you’d expect on a tube tester of this age.
This restored and calibrated Hickok 539B is clean, calibrated, and ready for service.
The manual is available to download here



This is one of the cleanest cases I’ve seen.

This Hickok 539B tube tester is $1,875 plus shipping to the lower 48 states only because of the weight.
Contact Me if you are interested in this tube tester.