Please watch the youtube for repair: https://www.youtube.com/watch?v=xdTP5gev3Ew
The failure mode is cannot power up. Root cause is due to supply to digital board supply NG. Changes D15, Q10, R77, R37 and Q16 (no need change as it still working). and set back to normal.
Note the cover is rusty and remove it and polish it to remove rust, then paint it with silver pen.
This is a faulty subwoofer and need repair, after check the pcb, it has been repair trial and see regulator transistor poorly soldered and loose joint. PCB trace on the pcb is weak and need careful repair and touch up all joints. First attempt is power amp board working but oscillation after plug in the pre and crossover boards. Later identified that the capacitors of +/-15V supply weak or not function properly. Thus replace all the E-cap on this subwooder and all working fine. Lesson learn is that Harman use cheap China capacitors and cause the problem not able to last.
You can see from the photo the tweeter has damaged foam but it does not affect the function! The the bass unit, the coil is open circuit and all 4 units (brought two more spare) are due to the corroded connection at the flex wire to the paper cone. Thus this is not internal open circuit and thus I try to reconnect them using a wire as shown. After repair, the driver can be used without any issue!
After I sold my Tannoy Turnberry, I buy a pair of smaller speaker from China. It was a ProAc 2.5 clone. The price is wonderful and I use this speaker till today! I have modified the internal film capacitors (3.4uF and 4.7uF) to Rifa film capacitors and it seems improve a bit in the mid and high frequency.
This is the biggest speaker I ever own so far. Due to its size and small room in Hong Kong, I have to gave it up after 3 years use in 2006. I use 300B to drive it but with its 90dbslp sensitivity, it is still unable to drive it to satisfactory sound level and quality. Later I build a Aleph 60 and it sound much better but the booming is still there due to small room effect. So I have to gave it up and sold it for 10k HKD!
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