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You know you're old when

T

Tom Wells

Needed to check that a full wave rectifier had opened the filament, opened the tube tester.
Found a couple stray tubes in there. Couldn't see the numbers.

There's a 6K6, theres a 5U4, theres some 6SN7 or L7s.

You know you're old when you know tubes by their shapes, and can look inside and read the construction.
 
Tom Wells said:
Needed to check that a full wave rectifier had opened the filament, opened the tube tester.
Found a couple stray tubes in there. Couldn't see the numbers.

There's a 6K6, theres a 5U4, theres some 6SN7 or L7s.

You know you're old when you know tubes by their shapes, and can look inside and read the construction.
Click to expand...

Ouch.

If you're having trouble reading the numbers on a glass-envelope tube, try sticking it in the freezer for an hour or two. When you pull it back out, sometimes the frost will be slower to melt off the number, making it briefly legible.
 
I could see 'em if they were there. This were the kind where the marking really does come off.

The freezer trick is good for the faded octal-badge and such old tubes.
 
I just suck in, hold my breath, and slowly fog up the glass to read that dissapearing stamp.

But Tom, you know you're really getting there when those tube designs are known by sight, but, they're Type 80, 42, 26...AND you know the filament connections to test with a VOM.
 
amfmsw said:
I just suck in, hold my breath, and slowly fog up the glass to read that dissapearing stamp.

But Tom, you know you're really getting there when those tube designs are known by sight, but, they're Type 80, 42, 26...AND you know the filament connections to test with a VOM.
Click to expand...

That's exactly what struck me, I didn't need the numbers on them or dozens of other types.
I don't even need to grab the substitution book for most old receiving types.

Shucks, all them old ones are easy. The filament or heater has the fatter pins.

I always liked the mesh plates of '32s and 34's with the grid cap on top. I'm old.
 
Shame on me

Pt 15 tube AM with Van der Bijl (grid mixing low level ) modulator.
Not only had the full wave 5U4GB died, within thirty minutes the spare opened filament.
I worried for 3 seconds and plugged in the new one.
Main fuse which is set real close to draw hadn't blown.
NEW one worked great, and solved mystery of lowered output.
I should have been paying attention to the ever decreasing size of the "conduction spot" inside the VR tube on the oscillator.
Or I should be logging some hour charts.

The '34 voltage amp tube is 70 years old and has been on over well 99% duty since the early 90's.
Spect I oughta check tubes more often? I run them real conservatively on purpose.

It's hard for me to check the oldies, cause the oldie tester has the row of levers to flip up or down, not rotary knobs.
The oldie has a chart recogizing the number-letter-number designations, but not all the mid-30's number types?
Then I have to get out the subs booklet and read the chart for the newer designation.
And then it's emission test onlly. Newer checker is transconductance, but lacks 4, 5, 6, 7 pin sockets. :(

I run brake shoes until they just touch the backing and almost gouge the drums. Depression era mentality, I guess.
 
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