Yamaha Natural Sound Stereo Receiver RX-750

[Carol2]

I have a Yamaha Natural Sound Stereo Receiver RX-750 (purchased maybe around 1992-1993?). The input selector switch doesn't seem to be working properly. No matter which input I select, the sound is fuzzy and static-y. If I jiggle the knob or press and hold it in tightly, the sound will clear up, but often goes right back to fuzzy as soon as I remove my fingers. I have to keep playing with the knob until I finally get clear sound.

It has been suggested that I repair this using a contact cleaner. I successfully removed the cover from the stereo and the knob from the front. However, with those removed, I am in unfamiliar territory. Where do I squirt the contact cleaner? I am assuming it would be on the front side of the panel where the knob was removed, not on the back side inside the box. However, looking inside the hole where I took the knob off, I'm not sure where to start squirting. Should I just set the stereo up on end and squirt all over the stem? What is the proper technique for applying the cleaner? Here are photos:









If that is not the right approach, can this be repaired on a unit so old? Is this unit worth repairing? (It was quite expensive when I bought it.) Can I repair it myself if I get parts? How difficult? Inside and out, the unit looks immaculate.

Thanks so much!
Carol

[HayZee518]

take the metal plate off in your 3rd or 4th photo and look at the wafer switch that goes through the front panel. there is a center wiper and several contacts around a brown phenolic insulator. spray the cleaner on these contacts and rotate the wiper quickly back and forth. the cleaner will evaporate leaving a shiny surface for the wiper to travel on.

[Larry at Approved]

Cleaning the control may work ok, however Yamaha issued a replacement function selector switch with gold plated contacts to eliminate this problem. The new switches work great.

[Carol2]

Thanks! I still have not repaired this receiver. Is this part easy to install? Can you give me any tips?

[Larry at Approved]

You need to be able to disassemble the receiver to get the circuit board which the switch is soldered to out of the receiver, then unsolder the old switch, and solder in the new one. There are a lot of connections to unsolder, not so easy. We are a Yamaha authorized service center, have done a lot of these. We are Approved Audio Service in CT.

[Carol2]

Would you be able to recommend a good service center in the Jacksonville, Florida area?

[Larry at Approved]

I don't know of any. We get stuff shipped in to us from all over the US.

[HayZee518]

Larry, how good are you guys at repairing amplifiers? I got a mosfet karaoke amplifier that chit the bed. I sent it back to the company as it was in warranty and supposedly they repaired it. Upon receiving it, they changed the mosfet but I still get one channel - I need two!

[Carol2]

Hi Hayzee,

Would you please not hijack my thread and rather start your own new thread?

Thanks!
Carol

[Larry at Approved]

Originally Posted by HayZee518

Larry, how good are you guys at repairing amplifiers? I got a mosfet karaoke amplifier that chit the bed. I sent it back to the company as it was in warranty and supposedly they repaired it. Upon receiving it, they changed the mosfet but I still get one channel - I need two!

that's our business. what brand is it?