I opened TRIO/TW-31 and checked the inside as I showed here last week.
I can not understand it completely as far as I checked inside. First, I removed the largest capacitor and measured it. The measured figure was almost same as specified. I put it back and soldered it. I tried to remove another capacitor and took same procedure. The result was same and I could not understand what was wrong. I called the manager of Hi-Fi Do and asked the manager about it. He said, "Reparing cost might be JPY 30,000 to JPY50,000 ." His advice seemed irresponsible for me.
It might be better to give it up if you are not able to repair it. I turned it on. 17 ohm and 18 ohm were both leaking. The manager told me that the speaker will be broken in some day. I tied to carry out an experiment. I turned on power switch but no sound was generated. I turned on volume and I could hear the sound slightly. The position of 8 o'clock can generate good sound. I changed the position of 9 o'clock. The volume of sound is getting better and turn it more, then it did not sound at all. It was broken. I regretted that I should obey the manager's advice. I was disappointed to break one speaker.