Yes, the speaker had been burnt. I had to connect another spare speaker.
The speaker problem is now sorted. It turns out that the pins on the input power socket at the back, the some of the wires were bent, and they were shorting each other. I put the torch on, and separated them with flat screw driver, and the 13.5VDC on the speaker wire has disappeared.
And connected a spare speaker I had, into the speaker wire, powered on, and it worked.
But the new spare speaker was too large at the back, and it wouldn't fit into the casing, and I had to connect it from outside of the casing. It looks not neat, but it is working.
I did some tx testing. CW works OK, but ssb tx is problem. When mic keyed up, the output keeps jumping up and down making whining noise from the speaker. It looks like it is outputting some FM or AM modulation with carrier but it cycles on and off while making noise.
And 40m and 80m band output is very low, about half a watt. I tried to tune it with the Tune knob on the front facia of the FT7, but it only peaks another 100mW.
Problem after problem with this FT7.
