Popular vintage transistor power amplifier in the 1990s INKEL AX-7RA

Описание: This is a once popular transistor INKEL AX-7R audio power amplifier produced in 1994.
A few months ago, I found a broken amplifier on a second-hand trading site.
The breakdown of this amplifier, which has been more than 30 years old, is that one channel does not work.
I analyzed the cause of its breakdown in detail.

I found out that the mechanical cause of the breakdown is the frequently used parts.
For example, the power switch, the volume control for adjusting the sound, and the input selection switch.
It could also be caused by dust that has accumulated over 30 years.

There were several causes of the breakdown.
1. The dust in the RCA jack had been left for 30 years, so I
cleaned it with a dry cloth soaked in alcohol.
2. I opened the inner cover. The inside was full of dust.
I used a vacuum cleaner and a small brush to remove the dust, and washed the attached dust with alcohol to remove it.
3. Elimination of causes of selector switch and main volume contact failure.