The wacky world of tubes...

[w3bny]

As all you boatanchor weenies and wanna be weenies know, the mystique of the boatanchor is in those glowing beauties we call vacuum tubes. Your cat calls them "a nice place to take a nap". Also, as we guys and gals know, we need a way to find out if these guys are bad or not. Enter the tube tester. Back in the day you could go into just about any shack (or Radio Shack for that matter) and get your suspect tested to confirm yes its bad or "sorry charlie, try again". Well I got a BK707 tester that I got a couple (about 8 ) years ago. I was gonna sell it but now that Im in the boatanchor business, discovered I needed it. Some FB OM out there said I needed to do the calibration on it. Ok looked it over and seemed ok. Put a tube on it and bad...lets try another...bad...wait a second...bad...every tube I have cant be bad...yeah that one was bad too! Then i remembered that someone gave me a Knight tube tester (the one with all the lever switches and the roll chart) anyway thats the only thing I had to even verify that all the tubes were indeed bad (or at least suspect) or that the 707 was FOOBAR.

Got it out, hooked it up to a Variac and slowly dialed up the voltage over 30 minutes till it came back to life without any arky-sparky or electrolytic caps going esplode! I must say its kind of a confusing beast but put a tube in and good....good again...hey this one is good....in all I have only 1 suspect tube but not for sure since the Knight is suspect as well. So now it looks like I might be able to get the Knight back in full calibrated service easier than that 707 so I can progress onward with the boatanchor referbs.

Moral of the story.... If you do not have a WORKING CALIBRATED tube tester. GET ONE because its all about the tubes baby.

PEH!

[n2ize]

Most of the time you don't need a tube tester. Most old tube rigs can be diagnosed better without one. For example a tube can show good on the tester yet be soft in the circuit. Very few of the old timers had tube testers yet kept their rigs running.

[K7SGJ]

Most of the time you don't need a tube tester. Most old tube rigs can be diagnosed better without one. For example a tube can show good on the tester yet be soft in the circuit. Very few of the old timers had tube testers yet kept their rigs running.

True, but tubes were a nickel ninety-eight back then, and you could afford to have many spares. I always said, the best tube checker was the device the tube was in. Well, I didn't ALWAYS say that...........now that I think about it, I never said that. Never mind..................

[XE1/N5AL]

...Back in the day you could go into just about any shack (or Radio Shack for that matter) and get your suspect tested to confirm yes its bad or "sorry charlie, try again"....

Even the corner drug store had a tube tester and an assortment of commonly used tubes. Then, all of that stuff quietly disappeared; and apart from ham radio operators, I'm not sure that anyone really noticed.

[K7SGJ]

Even the corner drug store had a tube tester and an assortment of commonly used tubes. Then, all of that stuff quietly disappeared; and apart from ham radio operators, I'm not sure that anyone really noticed.

All the drugstore tube checkers ended up stored in old phone booths, where ever they are.

[NQ6U]

All the drugstore tube checkers ended up stored in old phone booths, where ever they are.

Superman keeps all the phone booths in his Fortress of Solitude.

[K7SGJ]

Superman keeps all the phone booths in his Fortress of Solitude.

Well there ya go. Have that guy with the big red S check your tube.

[NQ6U]

Well there ya go. Have that guy with the big red S check your tube.

That would be super, man.

[K7SGJ]

That would be super, man.

Especially the kyrpton vapor regulators.

[w2amr]

I have a TV-7 military surplus tester from fair radio, and it works great. I don't know if they are available any more. Yeah I know, lots of knobs.
http://img692.imageshack.us/img692/7483/tv7utubetester.jpg

[K7SGJ]

I have a TV-7 military surplus tester from fair radio, and it works great. I don't know if they are available any more. Yeah I know, lots of knobs.
http://img692.imageshack.us/img692/7483/tv7utubetester.jpg

Now all you need is a civilian tube tester and you'll be set.

[NQ6U]

Now all you need is a civilian tube tester and you'll be set.

Or, his tubes could just enlist.

[kb2vxa]

He's a drug store tube testin' ham
He's the head of the Ku Klux Klan
When summer rolls around
He'll be lucky if he's not in town

Well he's got him a shack on the hill
He plays country records till you've had your fill
He's an AM Gangsta, and an all night DJ
But he sure does think different from the records he plays

[XE1/N5AL]

Or, his tubes could just enlist.
After an honorable service, they could study under the G.I. Bill to become transistors.

[kb2vxa]

They don't have to study, haven't you made any of those plug in transistorized tube replacement things? No, not rectumfryers, appleflyers.

[koØm]

I have a tube tester, the Eico Model 628, tests all the small tubes FB but,

https://forums.hamisland.net/attachment.php?attachmentid=12923&stc=1

It has a 12 pin compactron socket but, no data for testing sweep tubes like the 6LF6, 8950 or other tubes like 7581, 8908, or 8950. No information on 6JE6-6LQ6 either.

By looking at the details of the switch positions for a known tube like a 6BQ5, I determined what state the tester was placing the various elements of the tube at when testing, and, I transferred the extrapolated info to that of the tube I needed to test whose setting were not on the roll.

It just taking up space and collecting dust; it's going on the table of the next ham flea market.

.

[w0aew]

What was to prevent the Rat Shack & drugstore testers from being intentionally set to bad (or allowed to go out of calibration) to sell more tubes?

[K7SGJ]

What was to prevent the Rat Shack & drugstore testers from being intentionally set to bad (or allowed to go out of calibration) to sell more tubes?

You always tested the new tube to make sure the tester wasn't fubared. As I recall, most all of the tube testers I ever had, or worked, on didn't have any internal calibration pots. All the variable pots/switches were user controls to set filament voltage, grid, screen and plate voltages. I suppose an internal resistor in the divider could go bad, but if it did, you would catch a problem when testing the new tube, or even testing your other tubes, as they would most likely test bad as well. At that point, I would have had someone at the store pull out a tube or two from stock and test it.

[kb2vxa]

Rat Shack wouldn't fiddle with a tester, they sold Gold Line tubes with lifetime guarantee (not that of the tube smarty pants) and gold plated pins. I had a transmitter that ate finals and returned them every couple of months. It took over a year for bright boy Ed Krisko the manager to ask "You're not using them as sweep tubes, are you?" I don't know if he came in a can, I never asked.

[K7SGJ]

Rat Shack wouldn't fiddle with a tester, they sold Gold Line tubes with lifetime guarantee (not that of the tube smarty pants) and gold plated pins. I had a transmitter that ate finals and returned them every couple of months. It took over a year for bright boy Ed Krisko the manager to ask "You're not using them as sweep tubes, are you?" I don't know if he came in a can, I never asked.

Yeah, they lost their ass on me, too, with that lifetime guarantee crap.

[n2ize]

I have a tube tester somewhere in the back of my closet. mostly use it for checking small receiving tubes. large power amplifiers and final amp tubes are easy enough to test by just looking at how they perform in the transmitter.

[XE1/N5AL]

I don't have a tube tester. But, I do have a Sencore CRT tube rejuvenator, which is good for getting extra life out of an old oscilloscope, spectrum analyzer or network analyzer CRT. I'm not exactly sure where it is, though.