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ART WITH TUBES
Dear Sir,

I am a collector of vintage TV cameras, test equipment and the like. I have purchased many items which became or were disassembled or incomplete. as part of my interest i am desiring to take some of the old tubes and create an art object -- a light -- out of them. please forgive my desire to take the original purpose from the tubes and apply a different one to them. I hope you don't consider it blasphemous. nevertheless, i do believe them to be quite lovely and elegant. it makes me proud of American ingenuity.

Here are my questions:

Q
Are there any dangers i should be aware of in dealing with vacuum tubes?
A
If you don't break the tubes there are no dangers what ever. If in the process of creating art you do break the glass there could be. Many tubes used toxic metals and other substances which have been found to be toxic and/or carcinogenic. Some rare tubes contained mercury and some others not so rare but not really common had radio active material inside. Even this is not dangerous unless the tube is broken and the insides disassembled.
Q
Is there any glue that marries glass to glass (glass tube to glass box)
that will withstand a not so great amount of heat
(the heat would come from incandescent bulbs under 100 w)?

A
I'm afraid I'm not an expert on glues. I remember something from my youth we called airplane glue, as in model airplanes, that would glue about anything to anything. I think it was clear after drying which is likely what you want.

Thank you for your consideration.
Very interesting. I'm not going to be judgmental about your art activities.
Best Regards.
Max (Tube Man) Robinson
To see the tube lamp click here
GENERAL INTEREST:
Some of these questions were asked about Silvertone wire recorders but they have applications to any tube electronics device. Just ignore the references to wire recorders and take it as applying to your problem.
Q:
I replaced the cord already, but not with a fusible end. Does it need the fuse?
A:
If I were you I would put a fuse in the line cord if there isn't one in the radio chassis somewhere. In the best case a fuse can keep you from having to buy a new rectifier tube and in the worst case it can save you from having to build a new house. Fuses are well worth the few cents they cost.
Q:
Do you have any idea where I might find a needle for my phonograph? I have tried several places. Oh well the search continues.
A:
For Phonograph cartridges try this URL
http://www.metcoelectronics.com/astatic.htm
I am fairly confident in saying that you need the whole cartridge not just the needle.
Q:
I am getting shocked sometimes on my radio. What can I do to correct that problem?
A:
That depends on whether your unit has a transformer or is line connected. Without a transformer (they were omitted to save money) one side of the AC power line is connected right to the chassis. If the plug is inserted in the socket so that side is neutral everything is fine but if you happen to plug it in the other way LOOK OUT! The chassis is connected to the "hot" side of the line and there is 120 volts between the chassis and anything that happens to be grounded such as a water faucet. You can actually light up a standard light bulb by connecting it between the chassis and the water pipe. If YOU happen to get in that position you might light up too. It's really nothing to joke about, it's DANGEROUS!
If you get a shock Reversing the plug in the socket may not do any good because in most AA5 radios the chassis would be hot when the set was turned off. I STRONGLY recommend a permanent fix such as replacing the line cord with one that is polarized and rewiring the power switch as described in the final section on the All American 5. You can buy polarized 6 foot extension cords for about a dollar at chain discount stores. Cut off the outlet end and replace the original line cord with it. Here I think safety is more important than authenticity.
If your radio, phonograph, or what ever has a transformer there may be small capacitors from each side of the line to chassis. One of these is likely leaky or even shorted. Find them and cut them out. You may want to replace them later if you experience interference from electric motors or a CB radio.
Q:
How can I test filter capacitors?
A:
A shorted filter capacitor can burn out a rectifier tube. Since many tube types are no longer being manufactured we need to conserve the ones we have. In a set I recently worked on there was a shorted filter capacitor which burned out one of the 35Y4 rectifiers. If you replace the tube and the capacitor is shorted the new tube will just burn out again. There is a fairly simple way to find out. With everything as it is put in a new number 47 dial light. They don't cost very much. It will come on bright for an instant and then dim down. As the rectifier tube cathode starts to emit electrons the light will brighten up again. If it continues to get brighter and brighter until it burns out, TURN OFF THE POWER IMMEDIATELY!!! The filter capacitor may be shorted. I say "may" because it may have become unformed and may need to be reformed. If on the other hand the dial lamp goes off like a flash bulb burning out as soon as the power switch is turned on the heater in the rectifier tube is open and the tube must be replaced. If you think you have a shorted capacitor, the only way to tell for sure is to test the capacitor under full voltage of 150 volts. If you have or can borrow a capacitor checker such as the old Heathkit IT-11 or IT-28 it has the perfect leak test built in. For details on how to use the Heathkit tester to test and reform capacitors click here. If you want to learn how to reform capacitors even if you don't have a Heathkit capacitor tester click the above link.
Q:
...good site for tubes radios etc.
I was a mechanical engineer for 38 years, the last 3 years I have studied electronics for my hobby. I am trying to make things with tubes especially radios but I don't know how . I have asked in my college but now-a-days few people know how to make things with tubes. Can you tell me how to do that? Thank you I am sorry if I bothered you
A:
It's no bother, that's why I am here. I'm sure you understand that no one could tell you in a few words how to build radios out of tubes. That is why my web site exists. The crystal radio is just a start. There are plans for building a number of one, two and three tube radio circuits. I suggest you start collecting old radio sets. They don't have to work but you can take them apart and use the parts to build your own radios. I am afraid that using tubes may soon become a lost art. That is the reason for my site. Good luck and keep me advised about your progress. Best Regards.
Q:
Sorry to bombard you with all these questions... I am going to either borrow or buy a tube tester as well.
A:
That's alright. I'm retired and have lots of time to help people.
Keep the electrons flowing and the tubes glowing.
Comment:
I am really enjoying your web site. I too built crystal radios, starting around 1943. My parts came from one Alva L. Allen, Clinton, Missouri. The crystal cost all of 25 cents and a single high impedance headphone was $ 1.25. By the way, the old lead mounted galena crystal is still available from Antique Electronic Supply in Arizona. 2000 ohm headphones are available also. I am a licensed amateur operator, W8TBK, and was licensed in 1954 while I was in the Army at White Sands Proving Grounds, New Mexico.
Also, I do use old braid for removing solder by heating it slightly and touching it into soldering paste. It works better than the commercial stuff as it will pick up much more solder. I also like working with tube equipment and have quite an assortment of old tubes. Thanks for a fine site.

WIRE RECORDERS:
Q:
My table model set is dead except for the wire/phonograph part. What would you suggest I try on that? All the tubes are in tight and I did take it apart and could see no obvious problems except for where someone tried to remove the black cardboard thing #C30 and cracked the base a little bit. When I went to pick this set up from the seller tubes were falling out of it and it didn't have the needle in it that he told me was there. Plus he said it turned on and lit up , but it doesn't.
A:
In these sets the motor is turned on and off by the turntable control switch only. This is so that if a user should forget and turn off the power switch on the radio while the wire is rewinding the motor will keep running and not stop causing a major wire tangle.
The black thing identified as C30 is a filter capacitor. They don't come out like tubes, they are soldered in place. In Silvertone wire recorders the tabs around the base are bent over and soldered to the steel chassis. In some other equipment the tabs are pushed through slots in a metal or phonolic mounting plate designed for the capacitor. The tabs are twisted to lock in place and wires are often soldered to them. You usually don't take one out in tact. Be sure you have a replacement before trying to remove it.
The first one or two digits of a tube number, before the first letter, are a guide to the heater voltage of the tube. If all the tubes have the same leading number such as 6 or 7 the set most likely has a transformer. If the leading numbers are 50, 35, 14, 12, 7 or 6 you have a set with series string heaters. These are like the old Christmas tree lights, when one burns out they all go out. You don't need hi tech equipment or rocket science to find a burned out heater. An ohm meter or if you don't have one a single flashlight cell and bulb can be used to test tube heaters. Their cold resistance is anywhere from 1 to 20 ohms. By the way if a tube tester shows a given tube down in the red that's not necessarily a bad tube. If the pointer moves at all the tube will most likely do something in the circuit. A tube has to be pretty far gone to stop a circuit from working completely. Another point, if the dial light is burned out by all means replace it. With it missing there is too much current running through the heater of the 35Y4 35Z5 or 35W4. If your unit has a different rectifier such as a 7Y4, 5Y4 or 5Y3 what I just said does not apply.
Good Luck.
Q:
I also just got a Heathkit it-11 cap checker like you suggested. which cap do I start with? How do I identify the filter capacitor?
A:
The filter capacitors are those round aluminum cans that are 2 or 3 inches tall and 1 and 3/8 inches in diameter. In some cases the metal can is covered with black or brown cardboard. There is more than one capacitor in each can. The large solder lugs connect to the positive side of each capacitor. The negative sides of all capacitors connect to the can and the company that made the electronics chassis for Sears bent the mounting lugs (around the perimeter of the can) over and soldered them to the chassis. One of the 35Y4s connects to an axial lead capacitor. It is a tube about 1 inch in diameter and 2 or 3 inches long and covered with yellow or brown cardboard. There is only one capacitor in this unit. Pin 7 of the 35Y4 connects through a thing which looks like a heavy braid cable which is actually a resistor. (Tube pins are counted clockwise starting at the key way.) The other end goes to an unused pin of the 35Y4 socket. From there a wire goes to a capacitor. A resistor will go from there to another capacitor and so on.
Q:
I put in a #47 lamp and it didn't turn on or burn out.
A:
That indicates no current in the heater chain containing that 35y4. There are two separate heater chains in a Silvertone wire recorder so some of the tubes may be lighting up and others likely are not. You can check tube heaters with an ohm meter or even a flashlight cell and bulb. The heater pins are 1 and 8. Those are the pins on either side of the key on the large center pin. You will likely find one of the tubes has an open heater.
Q:
Also, do I have to disconnect capacitors to check them?
A:
qualified no. You can check them for leakage in the circuit. Be sure the line cord is not plugged in. Connect the negative lead of the checker to the chassis and the positive to one of the capacitors. Set the lever on the left of the checker to "ELECTROLYTIC" and the one on the right to "DISCHARGE". After the checker has warmed up set the voltage switch to 150 and move the lever on the right down to "LEAKAGE". If the eye stays open, all of the capacitors are open, rather unlikely but possible. Most likely the eye will stay closed. After about a minute flip the lever back to discharge. The eye will flicker as you change the switch but should close for a few seconds then open. Go back to "LEAKAGE" and after about a minute turn the voltage down one step at a time until the eye opens. That is the voltage the capacitor can take right then without burning out. The checker gently urges the capacitor to tolerate higher and higher voltages until it reaches the value set on the voltage switch. This is a process known as reforming the capacitor. Leave it on over night. A capacitor which might have burned out if put into service at night can be good as new in the morning. I call this a Lazarus Capacitor and plan to put an article on my web page about it soon.
Q:
I have been working on my wire recorders. Is there any way of tightening the mechanism So that the wheels make better contact with each other? I just bought one on eBay and there are many things wrong with it. The set does not turn on. The wire part turns on but the wheels aren't spinning off of each other correctly.
A:
The wheels seem to be quite a problem in Silvertones. I now have two of them and one Pentron. Sears never made anything for its self. They always contracted out the manufacturing. They did have their own staff of design engineers. Pentron made wire and tape recorders for Sears to their specifications. Both Silvertones have plastic idler wheels. There MUST have originally been a coating of rubber on the rims and it has disintegrated over the years. The Pentron used conventional metal wheels with rubber tires on them. These have held up. I have gotten one of the Silvertones running by taking the rubber-rimmed wheels out of the Pentron and putting them in the Silvertone. In both Silvertones the original plastic idler wheels that drive the turntable had notches worn in them from being allow to run for a long time without turning. My brother has a lathe. I am going to send them to him to see if he can turn them round again. Because it is an idler a change in its diameter won't change the speed.
I've figured out the plastic wheels. They have to be very, very clean. First use a file to remove the surface layer of imbedded grime. Be careful not to get it out of round. Perhaps the safest way to do this is to use your electric drill to spin the wheel while holding the file on the edge of it. To get the drill to hold the wheel use a 10-32 screw and nut. Run the nut all the way down to the head of the screw. put the wheel on the screw and clamp the end in the chuck of your drill. This will ruin the threads on the screw but so what. Remember the nut is on the same side of the wheel as the head of the screw. After tightening the chuck as tight as you can, use a small end wrench or pliers to tighten the nut against the wheel. Now spin the wheel and use the file on the driving surface. This is the toughest plastic I have ever seen so don't be worried about taking off too much of the wheel. It can be damaged by high temperature so don't let it get too hot. If there is a notch worn in the wheel from being left to run without turning for a long time you need to find a friend who owns a lathe. OK let's say you don't need a lathe. Take the screw out of the drill chuck and the screw out of the wheel. Clean the rim of the wheel with a degreaser such as Orange Clean. In fact clean all of the driving surfaces with the cleaner. Put it together and see if it doesn't work better than you ever thought it could. As a matter of fact I spray some of the Orange Clean on a corner of a paper towel and apply it to a driving wheel while everything is running. The liquid will cause some slippage so you may have to help the turntable or rewind spindle a little to keep it turning. The liquid will dry fairly quickly and after it does the turntable will take off like Gangbusters. I think the Orange Clean must leave some kind of residue which is beneficial. Good luck. Hope it works as well for you as it did for me.
Although this makes things turn they are still quite noisy. It must be true that there was originally a rubber rim on these plastic wheels. I knew of three families who had these machines in the 50s. The recorders all ran very quietly.
Q:
I took apart the table model again and realized that the cam spring and lever are missing. Would that affect the alignment of the wheels at all? I don't really think so, but I thought you might know. It does affect the switch because when you turn it from off to on it doesn't "click" into position like it should. it works though. If you turn it from rewind to play, it just kind of skips by and goes into the off position. The only reason I knew that the cam spring and lever should be there is because my other one has it and I can see faint mark that it used to be there. Someone has worked on this before because it is extremely clean inside and it looks like a new motor was installed. I have been spending all my free time on these things. At least I am learning, huh?
Take care,
A:
These two parts are not absolutely necessary. The spring makes sure the rewind idler is not in contact with the motor wheel so it won't make noise during playback and record. The cam makes sure that the play/record drive idler gets in contact with the motor shaft when needed. You might try to make one out of aluminum. I don't think there is a lot of force on it so aluminum should work. I don't know about the spring where you could get one. Actually I think there is an advantage to going directly from rewind to stop. Less of a jerk on the wire. Maybe it was designed that way although none of mine do that. The rewind/play rocker mechanism won't work right unless all of the wheels are installed. You probably already knew that. By the way I have a Silvertone tape recorder from 1956. My parents bought it for me and I have kept it in working condition. It is in a portable carrying case. My brother has a 1958 model in a wooden cabinet about the same size as the wire recorder. He doesn't want it anymore so he is going to give it to me. He has kept it in working condition. The motors in the wire recorder and the tape recorder look the same.

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This site begun March 14, 2001
This page last updated October 22, 2003.