Joined: Jan Thu 01, 1970 1:00 am Posts: 1158 Location: Willington, CT USA
I have an old balloon style 80 rectifier tube with white "flakes" rolling around inside. Is this normal, or is it not safe to use? My tube tester doesn't test these old style tubes, so I have no way of testing. The filament checks good with a meter though.
Glenn
Joined: Jan Thu 01, 1970 1:00 am Posts: 28982 Location: Livermore, CA
Glenn
This is cathode coating that has flaked off. Some emission will be lost with that much flaking. If the tube still has enough emission it's safe and usable. Since you can't test an 80 try it in a radio.
Joined: Jan Thu 01, 1970 1:00 am Posts: 6187 Location: Minneapolis, MN USA
The number 80 in shoulder style (ST) is common as dirt.
The number 80 in globe style (S) can be rather spendy if you need to purchase one from a vendor.
Joined: Jan Thu 01, 1970 1:00 am Posts: 1158 Location: Willington, CT USA
I assume the newer "ST" type is backward compatible with the older "S" type tubes. I guess it just doesn't look right in a set of this time period.
Glenn
Joined: Jan Thu 01, 1970 1:00 am Posts: 8657 Location: Chesapeake VA
As far as the radio operation, it makes no difference...
I have one that has even more flakes than yours, works fine in a Radiola 18 and a Philco 610(yea It's too old for that one)... It does test a little weak and voltage(B+) in the radios is down slightly(vs a strong tube), but they don't seem to care...
Joined: Jan Thu 01, 1970 1:00 am Posts: 1158 Location: Willington, CT USA
Come to find out, my tester does have the 4 pin sockets for these old tubes.
Norm-
You were right, the tube tests around 50% for one half, and 55% for the other. It's a little low, but it should still work.
The good news is that all the other tubes in the radio test okay. I guess I got my money's worth for $20.
Thanks again everyone.
Glenn
