Problem with Audio Analogue Puccini stereo amp

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I've been having a problem with my amp for a while. Basically at times the left channel would seem to go mute. Sometimes it is, and sometimes it just plays at a really really low volume compared to the right channel. Well, it's not gotten worse, and seems to be happening "permanently". Earlier shutting down and powering up the amp would usually fix it, or tweaking the volume. Sometimes tweaking volume also caused some "scratching noise" to be produced by the amplifier via the speakers, I don't know enough about electronics to know if it is related.

So what could be causing this? Once or twice before I had a problem with blown small fuse or some such that I had to replace because it left the left channel horribly distorted, but this is different, there's no distortion or such, only low volume or no volume, and all the fuses appear intact.
 
By the sounds of it, you may have a dirty volume potentiometer (control) which needs cleaning. This is common on older amps and may also explain why one channel is much lower in volume than the other. Usually a squirt of electrical contact cleaner or DeOxit into the pot along with a few turns of the pot will loosen up the dirt and move it away.

With your amp, the volume control seems to be a sealed motorised type so cleaning might be a bit more difficult. Usually, you have to drill a small hole in the plastic casing and squirt some cleaner in there.

You will need to take the lid off it to do this and also may need to desolder the volume pot which may be quite difficult due to the fact that everything is attached to one board and trying to get one thing out will probably lead to having to remove or disconnect lots of other parts.
 
My version of the Puccini is the original, so the volume control isn't motorized, it's fully "manual" as it were. I'll look into getting some cleaner thingamabob, but I'm not sure what part of the volume control mechanism to clean exactly (yes, I'm really a noob with this stuff). I suppose I could take a picture of the thing as well, could be useful for any pointers.
 
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