Due to high workload on my primary job, I prefer to leave my serious listening session for a while. So if you are waiting for my Gainclone Project initial impression, perhaps you must wait a little bit longer. Sorry to say. Also my Duelund CAST Silver delayed to mid of March. It makes me also miss the Duelund sound so much. That’s also another reason to stay away from serious listening session, for a while.

I prefer to do simple pending task, like disassembly my Hickok 539B Tube Tester. This heavy tube tester really consumes my energy more than I expect.

Below is the general appearance inside the tester. Two rectifier, one is the “deadly” #83 Mercury Vapor Rectifier and the other is 5Y3GT Rectifier.


High quality and heavy transformer. Dark color lamination indicates high quality vintage material. Probably Z11 or even better (M6?).


The transformers appearance from the top. So many secondary taps, usually for the filaments. Some high Wattage resistor also laying around.


Hickok’s name is related with high quality build tester. As you can see, the resistors are all 1% tolerance.


Neatly build, perfectly soldered parts. I believe some parts value already drifted from the original one. Must check one by one and replace the necessary one.


The roll chart and the spring-test buttons.


Another view at the resistor behind the bias meter. I haven’t checked the function of this parts.


The VR Volt adjuster. Used when testing the VR Tubes.


Most of the cables are protected by the ferrite bead. This to improve the test result and stability. As you know, many cables are hanging around. Potential for interferences are everywhere.


The rectifier socket. One is UX4 for #83 and the other is Octal for 5Y3GT.


Another complete shoot from the top-side view.


The multi-jog-dial appearance from the back. The function is to select the parameter of tested tube. Thinking of number combination to open your safety box 😉 Wrong adjustment means wrong parameter and it means wrong result (lucky if it doesn’t blow away your tube) 😉


The short test selector. I could see at least 4 or 5 gangs on the selector. I don’t really want to know how does it work 😉


The function switch to select the MHOS/signal scale is even more complicated. If I remember correctly, the selector is 6 gangs and 8 positions. I do really don’t want to screw up this one.


High quality and nicely build transformer. The cables are arranged so neat, protected with some black sleeve. You can see that date marking showing Dec 1960. Now is 2010. So you are 50 years old tester!


The power adjust trimmer. Simple function, to adjust your input voltage to match the required value to run the tester accurately.


The Raytheon #83 Mercury Vapor Rectifier and RCA 5Y3GT Rectifier. The #83 is hardly used, I think. Need replacement soon, with Solid State one 😉