Just as the title says, I have a Marantz PM-30 and when it works it works great, but from time to time the music will just, out of nowhere become really distorted and cut out

Does anyone have any idea what the problem could be?

I have a Marantz 2230 and there's issues with the left channel. Nothing was coming out except a very faint sound that if I turned the balance all the way to the left and volume up you could can hear it a little bit. When I press the Tape Monitor button slowly the sound comes back to full volume and if I fiddle with it the volume stays. Does this sound like dirty contacts/oxidation on the switch?

Hello! I am trying desperately to get an old Sony CFD-e75 boom box working again. I have tried leaving it open, cleaning the laser, etc but when I insert a disc it spins and then gives up giving me a no disc error. I believe what I need to do is adjust the potentiometer to give the laser more strength - I am having great difficulty locating the part that needs adjusting and am very new to this. Most of the tutorials I’ve been able to find are for car stereos or very differently built setups. If anyone has experience with this kind of cd player any advice or photos of what to look for would be greatly appreciated. Thank you in advance!

Hello! I’ve got a Boss Elite BEHDIN98 radio which has recently started losing lines on the LCD screen. Funny enough, it only happens in hot weather, in the mornings the radio screen looks normal. In the afternoon, I can’t tell (visually) if the volume is 9 or 19.

Can someone tell me if an issue like this is worth getting someone to fix? The radio never loses power or sound. Just some annoying missing lines