One of these is rather inexpensive, though it may go up at the end of the auction. Radio Daze and AES have them, but they're expensive. If you can't afford one, there are other routes to take. If both deflectors do the same thing--they aren't controlled separately, a regular 6U5-6E5-6G5 will do the trick, though it'll only deflect on half of the target. There is another double deflecting eye tube. I forgot its number, but I can look it up if you wish. It is rather short in length, and only has the target section. It has no controlling triode. It is rather inexpensive usually. You can build an adapter for this tube using a socket and a tube base and a bakelite tube. This will also allow you to lengthen this tube to the regular eye tube length. Inside the bakelite tube you can hide a transistorized control circuit. I do not have exact specifications for the transistor(s) and other required parts, but it should be simple. Just about any transistor will do if provided with suitable voltage dropping resistors, etc. It should be easy to construct on a small piece of perforated circuit board (found at Radio Shack). The circuit may be slightly time consuming at first, but after it's built, you can re-use the adapter over and over again for each new eye tube that you purchase.
Also, if stuff is rattling around in the base of the original tube, this is probably the glue that holds the base to the glass--nothing to worry about. If you are worried about shorts due to loose elements, what you can do is put the eye tube in your tube tester. Then do element to element shorts tests while banging on the tube with your fingers. If the neon shorts light doesn't flicker or light up, then the tube will probably work well in your radio. Also, eye tubes don't draw that much current. If you're really worried, place a 1,000-5,000 ohm resistor in series with the B+ wire. Use a resistor that doesn't affect brilliance or performance. The value is quite flexible unless the radio's B supply is rather low (say around 150 volts). The resistor should be a 1/2 watt or smaller. You probably shouldn't go below 1/4 watt. Place a 10 MFD condenser after this and wire the negative end of the condenser to B-. You may also place a .25 ampere fuse in series with the B+ line. You may use this alone or with the resistor. Use a fast blow fuse. Even if your power supply doesn't put out 250 mA, the juice stored up in the supply's filter condensers should be enough to supply a momentary jolt that'll blow the fuse--should a short occur in the eye tube. If you don't feel like making an adapter or modifying the eye tube socket for a 6U5, or feel like putting out $50 for a new 6CD7, the fuse and/or resistor may be a great option.
Thomas
I don't know how you perform an element to element shorts test with your tester, as I don't have a schematic, and I don't own your tester. With my tester, which is an emissions tester, with normal settings you get a shorts indication between the cathode and any other elements (all other elements, except for internally connected to cathode supressor grids, are connected together with the plate--emissions test). To perform an element to element shorts test on my tester, with the pin levers, up is where you put the plates and grids, center is for filament voltage, and down is the common return. If you want to see if there's a short between one element and all others, you leave all others in the down position and then throw the lever for the element in question up. Vibrate the tube if you wish. Then proceed to the next element. Throw all levers down except the one for this element. If you throw one of the heater pin levers up, the shorts indicator will light if the heater is good (an obvious short). It won't light if the heater is bad. Same holds true for elements that use more than one pin. If you were testing, say, a 50C5, you'd get a short indication if you threw up the lever for either pin 2 or pin 5. The control grid is connected to both of these pins. This would indicate that the internal connection between both of these pins is good. To test for shorts between this grid and all other elements, you'd have to throw up both pins 2 and 5.
If you wish to test for a heater to cathode short, for my tester you'd leave both heater pin levers down, and throw up the cathode pin lever.
Kind of get the idea? Lots of wording, but rather simple in practice. If your tester is wired at all like mine (even if it isn't an emissions tester), you should be able to check for element to element shorts in your tube. If you vibrate the tube rather hard and can get no shorts indication between any of the elements, then you can be pretty sure that your tube isn't going to short your radio. If you wish, leave the heater pin levers in their normal positions and apply heater current to the heater while performing shorts tests. This will keep the cathode warm. On rare occasion heating the cathode can move things around and cause a short. Normally it doesn't.
If normally both electrodes in the neon shorts indicator light for a short, seeing only one electrode light usually doesn't mean that the tube has a short. It just means that the tube is a strong conductor or that its elements are spaced closely. I have some tubes which light the shorts indicator on one side once warm. They have no measurable shorts, however, and function well. If you question your shorts indicator, it is best to consult an instruction manual or to test the tube by other means.
Thomas
Thomas
Try re-soldering the pins. You could have a bad filament connection. Stick to soldering just the filament pins for now, as resoldering pins can be difficult, and if any solder drops down into the base, it'll short things out. Make a neat job and polish away excess solder with steel wool.
If this still doesn't fix the problem, then the filament is broken internally, and is opening due to thermal expansion. Sad because this is an expensive tube.
Thomas
Sometimes you get an old radio with a burned-out or very dim eye tube. The radio really isn't worth the price of a replacement eye tube. But a dark, dead eye tube sort of ruins the appearance of the set.
My idea is to remove the glass tube from a dud with a glass cutter or something. Then fashion a translucent, green, fake eye target - and somehow stick it inside the glass at the "business end." Then install a small 6-V lamp behind the fake eye.
Of course, the eye wouldn't open or close with the AVC voltage, but if properly done, it might look better than a dud eye tube?