I'm thinking of hiding a switch behind the set which would cut off the heater voltage to the eye. I would then switch on the eye to demonstrate to visitors, etc. When the heater is switched off, there would still be plate voltage on the eye.
Another idea is to put the heater circuit on a rheostat, and run it a reduced voltage for everyday use. I assume this would reduce the brilliance of the eye's display and slow the depletion of the phospors.
Can anybody see a problem with either approach?
I see no problems with either approach. Cutting or removing the heater power supply should turn the tube off or reduce its capability, at least.
Hope it helps.
Now, about a half year ago I put a nice new Russian eye tube into my Silvertone phonograph. It was REALLY bright. My phonograph's transformer puts out a maximum of about 200 volts! That isn't much. Why is my eye tube at about half brilliance now???? My Crosley 1117 has gone through about 2 eye tubes since I got it back in 2001. I do use it sometimes for 3 or 4 hours at a time, but I don't use it every day. I do use my phonograph practically daily, and for many hours, so this may explain something. My mother's microwave has been plugged in almost continuously since 1986, though! Its display hasn't deteriorated even half as bad as these eye tubes!
Interesting idea with dimming the cathode. Let us know the results you achieve. Sometimes this can contaminate the cathode. I have an article from the late 1940s describing a 2 tube capacitance relay. They suggest running the filaments a bit dim if the unit is going to be used for long periods of time (such as for trick store window displays). I've heard of others speak of cathode contamination when the cathode is run dimly. All I can say is give it a shot and see what happens. I know that with any eye tube the display dims noticeably with only slight reduction in heater voltage.
T.
http://hem.passagen.se/communication/vfd.html
Rich
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:What gives with eye tubes anyway? The CRT display on my mother's 1986 Quazar microwave has been burning brightly all these years. It still is quite nice, though it does have some dim spots. Their VCR of the same make and slightly older vintage (1984) has a display that performs comparably. Many cars of to-day have CRT mileage displays (funny that they are using tubes so much for this in an era that prides itself in solid state technology...guess the beauty of the green display is still so irresistable just like the eye tube...they have other colors now, too....Chrysler has an orangish-red symbol that flashes for seatbelts, and a bluish one for the brights lights....all on a CRT!). Maybe they're not called CRTs....whatever they are, they have a phosphorescent display with little orange filament wires running in front, which obviously give off electrons.
:
:Now, about a half year ago I put a nice new Russian eye tube into my Silvertone phonograph. It was REALLY bright. My phonograph's transformer puts out a maximum of about 200 volts! That isn't much. Why is my eye tube at about half brilliance now???? My Crosley 1117 has gone through about 2 eye tubes since I got it back in 2001. I do use it sometimes for 3 or 4 hours at a time, but I don't use it every day. I do use my phonograph practically daily, and for many hours, so this may explain something. My mother's microwave has been plugged in almost continuously since 1986, though! Its display hasn't deteriorated even half as bad as these eye tubes!
:
:Interesting idea with dimming the cathode. Let us know the results you achieve. Sometimes this can contaminate the cathode. I have an article from the late 1940s describing a 2 tube capacitance relay. They suggest running the filaments a bit dim if the unit is going to be used for long periods of time (such as for trick store window displays). I've heard of others speak of cathode contamination when the cathode is run dimly. All I can say is give it a shot and see what happens. I know that with any eye tube the display dims noticeably with only slight reduction in heater voltage.
:
:T.
Another way would be to adjust B+ voltage on the target. With a new eye tube you could start out around 100 volts turning it up as brightness goes down.
Lower voltage will also cause the eye to be more sensitive. On a 6U5 - 22 volts closes the eye using 250 volts. It takes less AVC voltage to close the eye at lower supply voltage.
Norm
:Thomas,
:What you call a CRT is actually a VF... vacuum fluorescent display. Not really very different from the old eye tubes. The VFs have a filament and phosphor coated electrodes.
:
:http://hem.passagen.se/communication/vfd.html
:
:Rich
:^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
:
:
::What gives with eye tubes anyway? The CRT display on my mother's 1986 Quazar microwave has been burning brightly all these years. It still is quite nice, though it does have some dim spots. Their VCR of the same make and slightly older vintage (1984) has a display that performs comparably. Many cars of to-day have CRT mileage displays (funny that they are using tubes so much for this in an era that prides itself in solid state technology...guess the beauty of the green display is still so irresistable just like the eye tube...they have other colors now, too....Chrysler has an orangish-red symbol that flashes for seatbelts, and a bluish one for the brights lights....all on a CRT!). Maybe they're not called CRTs....whatever they are, they have a phosphorescent display with little orange filament wires running in front, which obviously give off electrons.
::
::Now, about a half year ago I put a nice new Russian eye tube into my Silvertone phonograph. It was REALLY bright. My phonograph's transformer puts out a maximum of about 200 volts! That isn't much. Why is my eye tube at about half brilliance now???? My Crosley 1117 has gone through about 2 eye tubes since I got it back in 2001. I do use it sometimes for 3 or 4 hours at a time, but I don't use it every day. I do use my phonograph practically daily, and for many hours, so this may explain something. My mother's microwave has been plugged in almost continuously since 1986, though! Its display hasn't deteriorated even half as bad as these eye tubes!
::
::Interesting idea with dimming the cathode. Let us know the results you achieve. Sometimes this can contaminate the cathode. I have an article from the late 1940s describing a 2 tube capacitance relay. They suggest running the filaments a bit dim if the unit is going to be used for long periods of time (such as for trick store window displays). I've heard of others speak of cathode contamination when the cathode is run dimly. All I can say is give it a shot and see what happens. I know that with any eye tube the display dims noticeably with only slight reduction in heater voltage.
::
::T.
T.
Thomas,
I think the modern phosphors may be more efficient and the spacing of electrodes is probably closer.
I have an old Heathkit signal tracer from the early 50s and the eye tube still works fine. I think the tube was WW II surplus. Heath bought a lot of MIL surpluse when they started out in business.
Rich
I've found the same thing with 1629's, WW2 surplus. They often have bright green even after a lot of use. 6U5's made in the 1970's still seem to lose brightness.
Originally thought equipment using 1629's wasn't on all the time like radios?
Norm
::Awesome....was wondering what their name was. Still, why do they last so much longer than eye tubes????? Interesting that they only run on 14 volts.
::
::T.
:
:Thomas,
:I think the modern phosphors may be more efficient and the spacing of electrodes is probably closer.
:I have an old Heathkit signal tracer from the early 50s and the eye tube still works fine. I think the tube was WW II surplus. Heath bought a lot of MIL surpluse when they started out in business.
:Rich
:
Thomas
Thomas