I was hoping you would reply when I made the first post. I knew you had the background and the stock to know about it.
Yes, they couldn't just throw away everything that didn't say "ON' or "Freescale."
I have some tube testers from repairman businesses and they are emissions testers. One has "Nash TV" painted on the side. All of these bad tubes I find test like new for emissions. It is gm where they fall down. The emissions tester would tell them if it was dead or shorted and they used trial and error to find one that would work in a TV. This is probably one reason why the typical caddy has so many used tubes in it..........trial and error method.
The testers at the convenience stores, radio shack, etc were only emsisions. There were companies that sold seconds and used tubes in boxes with micro-writing on them. They checked fine for emissions.
What you said about the 6V6GTs rings a bell. I read a manuf. service sheet from the early 60s in the library that said the shelf life of a tube was only meant to be 3 years due to potential air leaks. I have wondered if the pin seals have anything to do with the situation. Possibly, they just made them and sold them in hopes that no one would check them for gm.
Some of these 5-packs all have the same date code so maybe they are just factory duds. I doubt that they all went bad together. I don't see this sort of thing with Euro tubes.
The Asian invasion began in 1964 and by 1968 the transistor had taken over in audio and radio. This is why there has been so much distributor stock laying around. There was a drastic reduction in quality control and then a massive market shift. Solid state TV took many more years.
I was told by a counterman in the late 1990s that in the late 1960s the manuf. dropped the quality control and went to an honor system where the repairman/customer just brought it back for an exchange. This opened the door to a situation where there was a market for visually acceptable tubes. He said he just took the tubes and the rep would swap for new ones.
I also recall someome saying that when he serviced mobile radios he would never use an RCA tube because they simply would not work. This hints of lack of quality control, poor gm.
There are transceiver websites that talk about how a Sylvania power tube is the only way to go. I was also told that the Zenith TO works much better with a Sylvania 1L6. This probably has to do with the factory tolerances for gm.
There are many former WE phone employees that post on forums. I found one last night that said the conversion to solid state switching system cut the failure rate drastically. These were WE tubes.
There is a very good website that tells about large lots of defective 5965 (computer rated 12AV7 with no quality control for noise or microphonics) tubes in an old mainframe computer. Some sort of inferior coating caused an emission that shorted the tube. This sort of thing could get expensive.
There was a large line-up of late color tubes like the 6LU8. Perhaps they were designed and applied in haste.
All-in-all it looks like tubes are difficult to make properly without a high defect rate. The employees sat all day and did something similar to sewing.
What is tragic now is that people evidently piled up crates of factory rejects for one reason or another and are now putting them into the market place. There was a market for them all along for reboxers like Standard Brand ("this tube may be used or a factory second") and other similar "suppliers.".
I bought some $1 ea 25L6GTs from AES in their tube sale a few years ago. Not a $5 tube for a dollar, a 25 cent tube for a dollar. They were branded SUMMIT and many were shorted and weak for gm. I have no doubt that these were factory rejects. Summit is still in business and has a website.
Motorola tubes are usually premium GE. They are some of the best tubes from what I have seem. Motorola and JAN military are almost always excellent.
One redeeming factor: I have found that many new tubes will come to life with 20-30 seconds of filament overvoltage. This is a B&K 707 that has enough of a power supply to put enough current through them to get them going. Hold the test button down for the last few seconds of the overvoltage and the hold it down until the gm starts to come up. It works about 25% of the time, on new tubes with both gm and emissions problems.
I read last night that when they flash the getter they use RF heating. It is conceivable that some of it gets on the grid.
