Aesthetix Io strange behaviour

I got it back today, working fine. Morten said he could find no other fault, except for blown internal fuses. The were "fast", and he said, even if the amperage is larger, such fuses often blow before "slow" fuses. As far as can be seen, the new regulator and the EL34 tube work fine, and there is no problem with the Synergistic active shielding cable.
So, the mystery has been cleared up, it was one bad tube (only), the second time it was wrong fuses (my fault).

Let me add that Glenn, at Aesthetix, has been of help through email.
In conclusion, this thread should not be seen as negative for Io or Aesthetix, but a user discussion of problems that can occur in all tube preamps, and how to solve them in this specific case.

Hi O holter
Yes, Glenn said they repaired and are on burnt in mode, should be getting my IO next week.
Yes my dealer said must use the same part otherwise it will degrade the sound, is all about right measurement of resistant and so forth.
Yes, is so painful but i am still enjoying my Sony xa-9000es cd/sacd .

Call Glenn , you could replace bigger said a 5 amps or direct the internal fuse with hard wire solder. My Callisto sgn. Also have internal fuse but my 2011 io do not have internal fuse. Yes my Callisto fuse blown too,
But since replacement is fine.
Chris

I am following this up, and will inform later. I am considering a Io upgrade in a larger context, named "chasing out distortion from my system". Happily my Io is back on line.

Although the Io now works fine, I have decided to ship it to the factory for an upgrade. Having to do without it during the repairs, and using replacements, made me realise that an upgrade will most probably be well worth it in my system, even if it is costly.