mercury rectifier tube

[timmy]

is there anyone that knows the right way to replace the mercury rectifier tube in a tube tester with diodes and a dropping resistor without damaging the tester. these tubes are expensive and if this tester will work the same without it then why not upgrade it with the diodes and resistor.

[bob91343]

You have a tube tester with a mercury vapor rectifier tube? That is strange. What is the type number?

Mercury vapor tubes are used because they have a low drop, so they more nearly approximate a silicon diode than a vacuum rectifier would. So in general, there are no precautions other than make sure you have sufficient voltage rating. To be on the safe side you can add a series resistor to drop about the same as the original tube.

[timmy]

the tube is a sylvania number 83 thats all it has on it. i inquired about this tube on ebay seen a tube listed 83 volt and he told me its not the same tube, it looked the same but he tells me mine is a rectifier tube but still says its different because its mercury and i can see just that inside and that mine dont mean its 83 volt and said i can use diodes and a dropping resistor to replace the tube.i dont know but i guess i have to take voltage measurements of the 4 pins i would assume 2 are ac and the other 2 would be rectified dc but i need to know how many volts.

[timmy]

well then again i just found on ebay a solid state replacement rectifier that plugs right in place of the rectifier tube and thats it, seems easier for 20 bucks saves me time and i certainly dont want to burn this tester up by accident.

[Reece]

Mercury rectifiers are used in certain tube testers, like HP. I have such an HP from around 1939 that works perfectly, and has the original big ST style 83 in it along with another original metal rectifier tube that I forget the number of.

[bob91343]

If I remember correctly, you could buy an 83 either vacuum or mercury.

I think $20 is a bit much, but if that floats your boat, go for it.

[bandersen]

Several of the early Hickok testers use an 83 and a 5Y3 like the I-177. I tried a solid state replacement in mine, but couldn't get the line adjust set properly. I suspect there aren't any dropping resistors in the SS device though since it runs cool. I ended up putting an 83 tube in there and it works fine. It sure does get hot though.

[timmy]

so would there be a difference between vacuum or mercury rectifier tube, would they work the same? if i tried a solid state what line is to be adjusted or how would this be done. thanks

[Reece]

Mistake: I said HP when I meant a Hickok T-53 is the tester I have. Brain freeze in this weather. It has a mercury 83 and a metal 5W4, both Raytheon brand.

[timmy]

the tester i have has both the mercury and a 6at6 tube as well.

[timmy]

i dont know what the 6at6 tube does so i have a spare coming as well as the solid state diode to replace the expensive mercury tube then i guess ill be ok for awhile.

[Tim]

Type 83 is Mercury and 83-V is vacuum. They are not interchangeable. The 83 has a constant voltage drop due to the mercury vapor and is why it was chosen to be used in this application.

Regarding the SS replacement - without the filament load of the 83 tube, the line adjust may not be able to be adjusted low enough to compensate for today's higher line voltages. One method to correct this is to run the tester from a variac to reduce the voltage to it.

[timmy]

there are a few pots for adjustments inside but i dont know what they are for. well ill see how the ss replacement does by checking a tube against the tube versus the ss replacement, comparison.

[bandersen]

Most testers have a line adjust control right on top. It's a big rheostat used to compensate for varying AC line voltages where you plug it in. There will be a line on the meter labeled line adjust too.

[timmy]

no theres no line on the meter for that adjustment.