How common is it to have a triode tube be "soft" or have low output several weeks or a few months after installation? (for instance the tube gives expected output at rated filament voltage but then cannot be saturated without increasing voltages in excess of of the rated filament voltage). Is this rare or common?
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Weak tube outputs?
- Thread starter radiofish
- Start date
The last set Eimac drivers that I put in were soft....fwiw. Never saw that before or with a different set of different make. They even "felt" differently before I put them...they just seem as "hefty" as the set I just removed.
K
kilowatt
Guest
Which tube??
> How common is it to have a triode tube be "soft" or have low
> output several weeks or a few months after installation?
> (for instance the tube gives expected output at rated
> filament voltage but then cannot be saturated without
> increasing voltages in excess of of the rated filament
> voltage). Is this rare or common?
>
> How common is it to have a triode tube be "soft" or have low
> output several weeks or a few months after installation?
> (for instance the tube gives expected output at rated
> filament voltage but then cannot be saturated without
> increasing voltages in excess of of the rated filament
> voltage). Is this rare or common?
>
K
kilowatt
Guest
I had been using nationals up until 8 years ago. Manufacturing was all over the place as far as China, France, etc.
After I spent a week with a McMartin in a cornfield (Linton) I gave up and ordered a set of Eimac drivers. Ugh. New tubes and fire out of the IPA because 1 of the pair wasn't right. Found out by placing the old drivers (weak) back in and getting output.
Another transmitter using two drivers and I went through two sets of Nationals until I convinced the owner to order Eimac tubes.
Now I am seeing the same type of problem with Eiamc tubes. Too bad Econco doesn't make these also.
Do you run at rated voltage for a week or so tyhen lower the filament until output drops. (Running below rated filament voltage. Gets longer life out of the tubes.
> The last set Eimac drivers that I put in were soft....fwiw.
> Never saw that before or with a different set of different
> make. They even "felt" differently before I put them...they
> just seem as "hefty" as the set I just removed.
>
After I spent a week with a McMartin in a cornfield (Linton) I gave up and ordered a set of Eimac drivers. Ugh. New tubes and fire out of the IPA because 1 of the pair wasn't right. Found out by placing the old drivers (weak) back in and getting output.
Another transmitter using two drivers and I went through two sets of Nationals until I convinced the owner to order Eimac tubes.
Now I am seeing the same type of problem with Eiamc tubes. Too bad Econco doesn't make these also.
Do you run at rated voltage for a week or so tyhen lower the filament until output drops. (Running below rated filament voltage. Gets longer life out of the tubes.
> The last set Eimac drivers that I put in were soft....fwiw.
> Never saw that before or with a different set of different
> make. They even "felt" differently before I put them...they
> just seem as "hefty" as the set I just removed.
>
C
CW
Guest
> Now I am seeing the same type of problem with Eiamc tubes.
> Too bad Econco doesn't make these also.
Twice in 816R5 CECs I tried Econcos.....both times were BAD out of the box (one never made licensed TPO, the other tripped all the breakers!)...
A NEW Eimac fixed it (YC130 which is a funky tube anyway!)
> Do you run at rated voltage for a week or so tyhen lower the
> filament until output drops. (Running below rated filament
> voltage. Gets longer life out of the tubes.
The correct way is run the filament at rated voltage (7.x or 6.x) for 200hours or more (I let it go for 9-10 days...easy to remember
then drop filament under power drop is noted, then raise fil voltage .2V and leave it..when power starts to drop off, you can then start to raise the fil voltage AFTER trying to raise the screen/plate voltage 1st! NEVER run the filament at below the rated voltage at start up..to do so poisons the tube and causes early failure.
> Too bad Econco doesn't make these also.
Twice in 816R5 CECs I tried Econcos.....both times were BAD out of the box (one never made licensed TPO, the other tripped all the breakers!)...
A NEW Eimac fixed it (YC130 which is a funky tube anyway!)
> Do you run at rated voltage for a week or so tyhen lower the
> filament until output drops. (Running below rated filament
> voltage. Gets longer life out of the tubes.
The correct way is run the filament at rated voltage (7.x or 6.x) for 200hours or more (I let it go for 9-10 days...easy to remember
then drop filament under power drop is noted, then raise fil voltage .2V and leave it..when power starts to drop off, you can then start to raise the fil voltage AFTER trying to raise the screen/plate voltage 1st! NEVER run the filament at below the rated voltage at start up..to do so poisons the tube and causes early failure.
K
kilowatt
Guest
I have had a problem with Econco tubes but here is why...using the same tube type...a tube for one transmitter will not work in another. You can't just call Econco and say send me a 3xc300a7. You have to specify the transmitter type. A 3cx3000a7 for a mcmartin won't work in a CCA. Wonder if this is the problem. Some folks stock the same type of tube for 2 different transmitters.
Now this is the final. Econco didn't rebuild 4cx250's. Is the r5 the 20K designation and is this a solid state IPA?
I have an older Continental 20k box and have had trouble with the solid state IPA retrofit in that it was stable for a year then became unstable. Tightening connections over and over during maintenance may or may not have solved the problem.
Thanks for the warning on low filament voltage in the first two weeks. have to say my lowering the filament voltage almost never takes palce as early as I hope. Do you get to your site every week if it is 2 hours away???
> > Now I am seeing the same type of problem with Eiamc tubes.
>
> > Too bad Econco doesn't make these also.
>
> Twice in 816R5 CECs I tried Econcos.....both times were BAD
> out of the box (one never made licensed TPO, the other
> tripped all the breakers!)...
> A NEW Eimac fixed it (YC130 which is a funky tube anyway!)
>
> > Do you run at rated voltage for a week or so tyhen lower
> the
> > filament until output drops. (Running below rated filament
>
> > voltage. Gets longer life out of the tubes.
>
> The correct way is run the filament at rated voltage (7.x or
> 6.x) for 200hours or more (I let it go for 9-10 days...easy
> to remember then drop filament under power drop is noted,
> then raise fil voltage .2V and leave it..when power starts
> to drop off, you can then start to raise the fil voltage
> AFTER trying to raise the screen/plate voltage 1st! NEVER
> run the filament at below the rated voltage at start up..to
> do so poisons the tube and causes early failure.
>
Now this is the final. Econco didn't rebuild 4cx250's. Is the r5 the 20K designation and is this a solid state IPA?
I have an older Continental 20k box and have had trouble with the solid state IPA retrofit in that it was stable for a year then became unstable. Tightening connections over and over during maintenance may or may not have solved the problem.
Thanks for the warning on low filament voltage in the first two weeks. have to say my lowering the filament voltage almost never takes palce as early as I hope. Do you get to your site every week if it is 2 hours away???
> > Now I am seeing the same type of problem with Eiamc tubes.
>
> > Too bad Econco doesn't make these also.
>
> Twice in 816R5 CECs I tried Econcos.....both times were BAD
> out of the box (one never made licensed TPO, the other
> tripped all the breakers!)...
> A NEW Eimac fixed it (YC130 which is a funky tube anyway!)
>
> > Do you run at rated voltage for a week or so tyhen lower
> the
> > filament until output drops. (Running below rated filament
>
> > voltage. Gets longer life out of the tubes.
>
> The correct way is run the filament at rated voltage (7.x or
> 6.x) for 200hours or more (I let it go for 9-10 days...easy
> to remember
then drop filament under power drop is noted,> then raise fil voltage .2V and leave it..when power starts
> to drop off, you can then start to raise the fil voltage
> AFTER trying to raise the screen/plate voltage 1st! NEVER
> run the filament at below the rated voltage at start up..to
> do so poisons the tube and causes early failure.
>
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