A "What the..." moment
 

When I started testing the tubes from my CT-100, I found this one, the 6CD6 horizontal output:

http://70.36.238.5/ct100/IMG_0930small.jpg


I had heard that Radio Shack relabeled other brands for their "Lifetime" tubes, but this one was a bit unusual anyway, I thought. Then, I couldn't find the number anywhere on the tube, until I found this dim label (enhanced here):

http://70.36.238.5/ct100/IMG_0931small.jpg


Okay... It is not a 6CD6 after all, though it tests good as one. There was something rattling around in the base of the tube, so I decided to try to remove it and here is how it looked:

http://70.36.238.5/ct100/IMG_0932small.jpg


No wonder the Tung-Sol label was so obvious. It wasn't the original base at all! (The rattling was a loose blob of solder in there.) I cleaned up the pins, and now I have a good spare 6JE6 for my newer color roundie sets (though it is missing a few of the pins):

http://70.36.238.5/ct100/IMG_0934small.jpg


I wonder why someone would have gone to all that trouble. Do you suppose 6CD6s were either hard to find, or more expensive at one point (maybe in the late 1960s or the '70s)? Certainly now, with all of the ham radio (and illegal CB radio) amplifiers that use the newer sweep tubes, 6JE6s are much more expensive than 6CD6s.

Good grief...Talk about desperate! :yes:

Wow... someone went thru a lot of trouble there!

Would be very bad if that blob of solder shorted something out.

thats a first for me , that must have taken some time, might have been faster useing another socket creating your adapter and just plug the tube in .

To solder those pins and not crack the envelope is a feat, but Radio Shack did advertise those gold-plated pins, which probably helped.

I recall that RS tubes had a lifetime guarantee. Wonder if this qualified?

I actually cashed in on that lifetime guarantee a couple of times.... I'd say it was about 6 or 7 yrs ago. You could still get "long-life" tubes thru Radio Shk in the blue box. I brought in two 6GH8's that failed to run the color section in a set. Just happened to have two NOS Lifetime tube boxes... put the weak ones in there and brought them back. After the sales guy read the guarantee on the box, he ordered two new 6GH8's and had them mailed to me.

If I remember correctly, the guarantee is only valid if the item is used in the manner it was meant for... something like that in so many words. I doubt the above HO tube would qualify.

Well, this 6JE6 still tests good, so I will keep it as a spare. I am impressed that RS could still order new tubes for you only a few years ago, and for "free" as well!

One set I've been tinkering on is loaded with those Lifetime tubes, maybe half of them. Guess the original owner was a do-it-yourselfer. I carried a few weak ones in to my local Shack a few months ago and waited in line to talk to the oldest guy in the store (my age). Eventually he came back with the answer that, indeed, they would replace them for free...all I had to do was produce the original receipt! But, others (including several on the ARF) have mentioned getting free replacements, no questions asked, fairly recently. Probably depends on who you talk to.

That sure was a lot of trouble for that tube! The 6CD6, of course, is dime-a-dozen.

I thought for sure that the set used a 6CB5 originally, but I looked up the schematic. Maybe the later production sets used it, as the 6CD6 is a little taxed in that circuit. I know for sure that the 21" model uses a 6CB5, as well as the CTC4 & CTC5.

Really interesting when somone can hack a fix. CHris, buzz me on New phone, can blog when mobile!:scratch2:

I can verify that you can still get free replacement tubes from Rat Shack, but the new tubes will NOT carry the lifetime replacement guarantee. You also need to be persistent about it, and talk to the store manager, not the cellphone salesdroid behind the counter.

About 3 months ago, I was able to exchange a pair of gassy "Lifetime" gold pin 6L6GCs for a new pair. The manager had to call the regional office, who said that the warranty was still valid WITHOUT the original receipt, but that tubes were now a "special order item" and might take a while. It took almost 6 weeks to get the new tubes, which were Russian "Sovtek" branded.

6L6GCs are one of the relative handful of tube types that are still in production, however. You might have a bit more difficulty having RS replace a 6CD6 or a 6BK4.

If the tube specs were the same, and the pins were properly rerouted I'd have left the hack in unless I had the right type laying around in my parts bins.

I can imagine doing something like that if I didn't have the correct type on hand, and was strapped for cash. It is really amazing just how many ways there are to work around not having the correct part, and the resourcefulness that goes to finding those ways!

Wouldn't CT-100s have been shipped with 6CD6Gs? I was under the impression that larger straight-sided tubes were not introduced until later that year beginning with the 6CU6.

The Radio Shack “Lifetime” tube warranty brings back some G-Rated high school memories. Our radio club built (with a big assist from the CE of a local AM) a low power AM transmitter. With two 6L6’s and two 6LQ6’s… And, we used RS tubes from the very beginning. Two sets worth. Between our audio levels (We were Top 40) and the obscene:1 VSWR the output was seeing as a load, we were popping tubes at the rate of at least one a month! But, RS always replaced them for free. As for the “normal use” of these tube types…!