Yamaha cr-620 bass is lost in one channel

[YAKI]

Hi,
I have an old Yamaha cr-620 reciver. It sounds great for me, but one channel lost it's bass. I have only the high tones. Can you kindly help me with potential reasons for it? It is a problem in the reciver as swithing the speakers does not change the faulted channel. Thanks! Yaakov

 

[Mooly]

A few posibilities. A dried out electroylitic in the audio path, usually it's small value ones used as coupling caps that give trouble. Depending on the circuit it could be a faulty pot in the tone controls for example the wiper open circuit.
If the sound is extremely quite as well a very very tinny it could be open circuit print somewhere.
Caps are favourite Do you have a circuit ? What it's not, is semiconductors etc.

 

[Nico Ras]

Have you tried swapping the speakers, maybe the woofer coil is burned and it is stuck so you will only hear treble from it.

 

[Nico Ras]

Sorry I did not see you switched speakers. Mooly is right, look at changing electrolytic caps at the input. Also dry joints on the bass control. Have you got a tone defeat or bypass, try switching tone controls off and see if bass returns.

 

[YAKI]

Thanks

Hi,
Thanks for your kind help! I will chack it out. The schematics are here if it helps:

http://www.upload-il.com/?d=E863D4701
http://www.upload-il.com/?d=A0B665181

I will try to look for these capacitors. Hope I will locate them in the diagram. It is easy to me to find it in the circle, but I need to find them first in the drawings.

P.S. - When I turn the loudness knob to the maximimum, the bass comes back. Is it helpfull? Does it suggests a probelme with the Bass knobe?

Thanks,
Yaki

 

[Mooly]

What schematic ??
When you say you turn the control and it comes back, does it suddenly come correct --- that amy be the pot--- or is it gradual, as you turn the pot it increases.

Can you not scan the circuit and post that

 

[Nico Ras]

What schematic ??
When you say you turn the control and it comes back, does it suddenly come correct --- that amy be the pot--- or is it gradual, as you turn the pot it increases.

Can you not scan the circuit and post that

Hi Mooly,

I also tried to look for the schematic and only found some lovely Israeli girls.

Nico

 

[Mooly]

I was going to say check them out for bulges ( The caps of course ), but that could be taken the wrong way

 

[Nico Ras]

I was going to say check them out for bulges ( The caps of course ), but that could be taken the wrong way

I like nice tight butt, er.. bass I mean.