It's oscillating.
If you aren't a technician (nice 'scope by the way), I don't recommend you try to fix the amplifier yourself. It also will suffer from leaky capacitors that makes an invisible film on the board and components that eats the leads, eats the copper traces and is conductive. There are two things you can do. There are some new driver boards that were designed, just replace the old boards with these. The other path is to remove all the electrolytic capacitors and components in those areas and begin cleaning the board. The last one I did required 5 cleaning cycles and if those new boards had been available, I would have used them.
-Chris
If you aren't a technician (nice 'scope by the way), I don't recommend you try to fix the amplifier yourself. It also will suffer from leaky capacitors that makes an invisible film on the board and components that eats the leads, eats the copper traces and is conductive. There are two things you can do. There are some new driver boards that were designed, just replace the old boards with these. The other path is to remove all the electrolytic capacitors and components in those areas and begin cleaning the board. The last one I did required 5 cleaning cycles and if those new boards had been available, I would have used them.
-Chris
The fluid can be detected with a hot soldering iron tip. The smell is memorable. It is also going to coat the parts, so you must either clean or replace those too. Replacement is probably the safer plan.
This fluid is extremely difficult to remove. It can cause extremely high DC offsets at the outputs, therefore on the speaker. It can easily cause a fire in the speaker. These amplifiers should be serviced by someone trained for audio amplifier repair, and hopefully trained on Adcom.
You may not be helping your friend by insisting on servicing this amplifier.
-Chris
This fluid is extremely difficult to remove. It can cause extremely high DC offsets at the outputs, therefore on the speaker. It can easily cause a fire in the speaker. These amplifiers should be serviced by someone trained for audio amplifier repair, and hopefully trained on Adcom.
You may not be helping your friend by insisting on servicing this amplifier.
-Chris
Hi.. after some work now the amplifier work good without final transistor.. From input to the pilot working fine.. I have a question. I have mount ONLY ONE PAIR final transistor.. to try it, with 3 amps fuse and without signal and without load.
I use in series to mains a 200 W lamps, when I turn on the mains switch, the voltage on power cable of the amplifier go on until 140 V and then you can listen the click of the bypass relays (power resistor in series to mains), and then the voltage go down until 90 V. Considered 200 W lamps, and the voltage on a load, 90V on 240 V total, the result is 150 V on the lamp and 90 V on a load and considered the power comsumption of the lamp 200 W 150 V, is how the amplifier to have a 300 W of comsumpion.. WITH OLNY ONE PAIR OF FINAL ??? It is possible ?????
Would you try without lamps ?? Or you remount all final transistor before ??
The voltmeter measure out voltage... see you my video.. YouTube
I use in series to mains a 200 W lamps, when I turn on the mains switch, the voltage on power cable of the amplifier go on until 140 V and then you can listen the click of the bypass relays (power resistor in series to mains), and then the voltage go down until 90 V. Considered 200 W lamps, and the voltage on a load, 90V on 240 V total, the result is 150 V on the lamp and 90 V on a load and considered the power comsumption of the lamp 200 W 150 V, is how the amplifier to have a 300 W of comsumpion.. WITH OLNY ONE PAIR OF FINAL ??? It is possible ?????
Would you try without lamps ?? Or you remount all final transistor before ??
The voltmeter measure out voltage... see you my video.. YouTube
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