Hello, I have 5Y3GT Raytheon tube that only has four pins and when I test it on my B&K tube tester it reads beyong good, but all of the other 5Y3 tubes I have ever seen have 5 pins. Is there something special with this tube?
Thanks
david

Dave

Nothing special, only 4 pins are used on a 5Y3GT. Most have a 5th but it's not connected.

What do you mean by beyond good? If a tube reads very high could be gassy? Do you see a purple color when the tube is operating? If not it's just a good tube.

Norm

:Hello, I have 5Y3GT Raytheon tube that only has four pins and when I test it on my B&K tube tester it reads beyong good, but all of the other 5Y3 tubes I have ever seen have 5 pins. Is there something special with this tube?
:Thanks
:david

You do, of course, mean there is an octal socket with only 4 meetal pins attached to the socket, right? If so, that's fine bicause like Dave said, you only need four, and with the keyway on the socket, you can't put it in wrong. I'll wait for your answer on the "beyond good" and see about that when I get it.

Lewis

:Dave
:
: Nothing special, only 4 pins are used on a 5Y3GT. Most have a 5th but it's not connected.
:
: What do you mean by beyond good? If a tube reads very high could be gassy? Do you see a purple color when the tube is operating? If not it's just a good tube.
:
:Norm
:
::Hello, I have 5Y3GT Raytheon tube that only has four pins and when I test it on my B&K tube tester it reads beyong good, but all of the other 5Y3 tubes I have ever seen have 5 pins. Is there something special with this tube?
::Thanks
::david

Hello, I am using a calibrated B&K 707 tube tester and when I tested a bunch of other 5Y3 tubes they all would fall in a range from poor (30) to good (90) on the meter that goes to a hundred. This particular tube that only had four pins pegged the meter on the good scale. Did not show any shorts or grid emmission. I just thought it was odd.
DAvid

Hi David

Does the tube look the same inside as other 5Y3's? Some modern ones were being built differently with a cathode, more like a 5V4. If it's built this way voltage drop between plate and cathode will be less and test higher. Try testing your 5Y3 as a 5V4.

Although only 4 pins are needed most 5Y3's in the US were built with 5, one no connection. Maybe this tube was made in another country?

Norm

:Hello, I am using a calibrated B&K 707 tube tester and when I tested a bunch of other 5Y3 tubes they all would fall in a range from poor (30) to good (90) on the meter that goes to a hundred. This particular tube that only had four pins pegged the meter on the good scale. Did not show any shorts or grid emmission. I just thought it was odd.
:DAvid
:

If a tube is brand fresh unused new, it'll sometimes test really well. I have an 80 (5Y3) that is my only unused tube of this kind. I bought it new years ago. All other tubes I have acquired used. The tube pegs on the tester, and also shows emission almost instantly (hold down button while applying filament voltage).....a characteristic of a new cathode. As cathodes wear out, they take longer to emit electrons (require more heat).

Also, rectifiers don't have grids, so any mention of grid emission given by your tester is meaningless with such tubes. It should be disregarded.

Thomas