SOLID STATE REPLACEMENTS
There are some things to consider when using solid state solid state replacements for the #83 & 5Y3 tubes in Hickok tube testers. If this is done with no load on those tube's filament supply, the test readings will be inaccurate. Plus the DC voltages provided by the solid state devices will be higher as well. The increased voltage provided by the solid state replacements is not so much of a problem in and of itself because all the applied voltages will be a bit higher with respect to each other. However since there is no voltage regulation in these tube testers the lack of filament current draw (of the now missing tubes) will cause other voltages to rise significantly affecting all the test readings. The #83 filament draws 3 amps, the 5Y3 another 2 amps. That's a significant amount of current not to compensate for the lack of.
I have successfully replaced the tubes using solid state devices without altering the test readings by installing power resistors across the filament supply of the #83 tube to compensate the for tube's filament current. Adding dropping resistors in the plate circuit for the increased B+ were also installed. That's a lot of work for tube substitutions, 5Y3's are common and cheap. The #83 is more expensive but not rare. The resistors needed dissipate a lot of heat, so their location is an important consideration when making such a modification. Also, the resistor values are important. I will add that some use a 5Z3 as a sub for the 83 -not a good idea, there is a good reason the Hickok engineers choose the #83 tube to use in their circuit design.
I question the statements made by the internet sellers of the replacement solid state replacement for the No. 83 tube. These statements are miss-leading! and there is a difference in the test results. One example I've seen on eBay; the seller shows the test results with a photo of the meter clearly showing a higher reading when the solid state rectifier is used!? :(
BOTTOM LINE! - You can use solid state rectifier replacements provided you re-calibrate your tube tester. Calibration can be a tedious process on some models. If you are not sure how to do so and you value accuracy in your tube testing, save yourself some grief, it's best to use the tubes.