Many tubes have multiple sections, that 6BN8 is a dual diode and a triode, so the tester has multiple settings for the tube to test each section. You might consider always running the tester on a VARIAC so you can control the line voltage accuracy as you noticed the readings are sensitive to input voltage. A small 240:120 step-down transformer will work for your voltage conversion, looks like there is room to put it inside the case.
2 місяці тому+1
That is a basic emissions tube tester that works well for occasional tube testing. I started out with a tester similar to yours that was a kit that I built when I was probably 15 years old. I still have that tester but haven't used it years. I now have Hickok 539B, 600A and 6000 tube testers along with B&K 707 and 747 tube testers that are more accurate when testing for shorts, gas, grid emission and will test for transconductance.
for the switch have you looked at what we used to call "make a switch" RS sell a range called "NSF Rotary Switch" you just need to know the max number of switch positions to get the right head. worth a look
3:33 That looks like cadmium powder to me. Sometimes found in equipment from that era. If so, you want to be careful with it as it's really bad for your lungs.
I prefer fine FRP for repairs like that switch. You can even improvise if you can't find fine enough glass matting; ladies tights and any 2-part resin will do the job, at a push
This is a emission type tube tester. That means that it will test for internal shorts and that the cathode can still emit electrons. This is done by testing the tube as a diode and measuring the emission current. nothing more. The short test was the most useful function of this type of tester. A very basic tube tester to say the least. This type of tester was primarily made to sell tubes. I would not waste my time trying to convert it to work on 240 volts.
I wonder if the mains frequency affects the accuracy. As that's 120V, probably from N. America, it probably expects 60hz. Operating at 50hz "might" have a neg. effect???
You talk about adding a transformer from 240v to 110v, why not replace the existing transformer with a 240V to 6v +6v as the output would be 6v for the filament & a Nixie Tube PSU module with 150v to 240v? It would be safer for both yourself & the tube under test as the insulation on the fitted unit . Also less bulky & more flexible due to the voltage range available allowing testing of different tubes not already supported. Plus more accurate.
The existing transformer has many filament windings (common filament voltages are 5, 6, 12, 35, 50 and 117 volts). Finding a replacement would be difficult and expensive.
You could 3D print a star shaped clamp that clips over that broken switch between the various connections and holds the phenolic pcb together.
If nothing's going on on the other side just bond a rigid disc to it?
Many tubes have multiple sections, that 6BN8 is a dual diode and a triode, so the tester has multiple settings for the tube to test each section. You might consider always running the tester on a VARIAC so you can control the line voltage accuracy as you noticed the readings are sensitive to input voltage. A small 240:120 step-down transformer will work for your voltage conversion, looks like there is room to put it inside the case.
That is a basic emissions tube tester that works well for occasional tube testing. I started out with a tester similar to yours that was a kit that I built when I was probably 15 years old. I still have that tester but haven't used it years. I now have Hickok 539B, 600A and 6000 tube testers along with B&K 707 and 747 tube testers that are more accurate when testing for shorts, gas, grid emission and will test for transconductance.
It's nice to have a tube tester handy. I use mine once in a while. 😎
for the switch have you looked at what we used to call "make a switch" RS sell a range called "NSF Rotary Switch" you just need to know the max number of switch positions to get the right head. worth a look
3:33 That looks like cadmium powder to me. Sometimes found in equipment from that era.
If so, you want to be careful with it as it's really bad for your lungs.
Possibly zinc powder from degrading passivation too. Still, better safe than sorry; don't snort it!
I prefer fine FRP for repairs like that switch. You can even improvise if you can't find fine enough glass matting; ladies tights and any 2-part resin will do the job, at a push
BW-100 is recommended for all Electronic Switches and Contacts. It is not flammable and is completely Plastic Safe.
This is a emission type tube tester. That means that it will test for internal shorts and that the cathode can still emit electrons. This is done by testing the tube as a diode and measuring the emission current. nothing more. The short test was the most useful function of this type of tester. A very basic tube tester to say the least. This type of tester was primarily made to sell tubes. I would not waste my time trying to convert it to work on 240 volts.
@@johnlehman2157 too late
I wonder if the mains frequency affects the accuracy.
As that's 120V, probably from N. America, it probably expects 60hz.
Operating at 50hz "might" have a neg. effect???
You talk about adding a transformer from 240v to 110v, why not replace the existing transformer with a 240V to 6v +6v as the output would be 6v for the filament & a Nixie Tube PSU module with 150v to 240v?
It would be safer for both yourself & the tube under test as the insulation on the fitted unit . Also less bulky & more flexible due to the voltage range available allowing testing of different tubes not already supported.
Plus more accurate.
The existing transformer has many filament windings (common filament voltages are 5, 6, 12, 35, 50 and 117 volts). Finding a replacement would be difficult and expensive.