Hot U21-U15 270ohm

[henmyr]

Hi. I've rechecked B3 and B6 without finding any errors. The resistances measure as they should and I find no shorts.

However, I then measured the resistances with the 6080 in place. The resistance at 9 was as it should be, but the resistance at 7 was close to 0 ohm.

The resistance from 3 to 7 is 3K without the 6080 in place, as is 3 to 9.
When I put in the 6080 the resistance is still 3K from 3 to 9, but now 0 ohm from 3 to 7.

Then I measured the 6080 pins 7 to 6 and it shows nothing, but 7 to 3 show 0 ohm.

My guess is that the 6080 is faulty?

[Paul Birkeland]

Hi. I've rechecked B3 and B6 without finding any errors. The resistances measure as they should and I find no shorts.

Are you 100% sure that you don't have B3/B6 wired to 5 or 10 by accident?

However, I then measured the resistances with the 6080 in place. The resistance at 9 was as it should be, but the resistance at 7 was close to 0 ohm.

That's unusual.

My guess is that the 6080 is faulty?

I would go ahead and contact replacementparts(at)bottlehead(dot)com and request a replacement tube.  Be sure to include your name and paste a link to this thread in the e-mail body.

-PB

[henmyr]

Are you 100% sure that you don't have B3/B6 wired to 5 or 10 by accident?

Between B6/B3 and 10, I have 5.47K ohm.
Between B6 and B3 I have 5.94K ohm
Between B6/B3 and 5 I have * ohm (rising ohm up above 100K ohm)

I would go ahead and contact replacementparts(at)bottlehead(dot)com and request a replacement tube.  Be sure to include your name and paste a link to this thread in the e-mail body.

-PB

Thanks, I will do that.

[henmyr]

I've installed the new tube and the amp works now:)

I still have to deal with a little bit of scratching noise, but the original problem of this thread is solved now!