[Mesa 2x10"] Problem with disappearing highs during play

[byacey]

Thx for your comments. I'm glad that this is not an ear fatigue after all.

Solder splash on the wire was removed simply by scratching and the wire under the splash was in good condition.

At this moment everything I can do only by myself is to change the diaphragm in the tweeter. I don't have an audio oscillator and my soldering skills are poor.
My hope has gone... If diaphragm change does not bring any positive results, I will have to give the cab to the technician but I doubt that there is a competent one in my area.

Last thing. What is the yellow capacitor, with solder splash on it, responsible for? I checked it with multimeter and its impedance could't be measured (pikes on both sides).

Not wanting to confuse the issue, but depending on the horn driver, many have to be adjusted by ear, shifting the diaphragm slightly, and may even require adjusting the torque on the diaphragm screws to minimize the low order harmonic distortion. This is best done by an experienced reconer, as they know what to listen for, and are experienced in how to make the required adjustments.

For now though, swap out the diaphragm and see if that solves the intermittent issue.

 

[agedhorse]

These drivers have locating pins that lock in the diaphragm. The gap tolerances are wide enough that it's not a problem unless the part has been mechanically damaged.

 

[Pioter]

Thanks for replies. When new diaphragm is installed, I will let U know for sure.

 

[Pioter]

Hi to all.

Diaphragm replacement did not give me any positive result. I'm forced to give it to the technician... :/

 

[Pioter]

Hello once again.
Final update (I hope so).
Mesa is working correctly now! There were some "bad connections" in branching filter (?) and/or crossover electronics. Connections were fixed, re-soldered and ready to use. Technician said that he haven't had that sort of issue earlier in his career. Every speaker is in good condition. It is possible that due to changing frequencies connections were "floating" and the filter was freaking out.

Once again thank You all for time and comments!

Good luck guys!

BTW it looks like @agedhorse was right in this case

 

[agedhorse]

Sometimes, simple seeming problems end up being trickier than first imagined. This is where experience and knowledge plays a role in getting it fixed properly IMO.