Yamaha cr-620 bass is lost in one channel

YAKI · 11th December 2008, 10:10 PM

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 · 12th December 2008, 04:27 PM

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 · 12th December 2008, 06:53 PM

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 · 12th December 2008, 06:57 PM

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 · 13th December 2008, 01:39 PM

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 · 13th December 2008, 04:12 PM

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 · 13th December 2008, 04:52 PM

Quote:

Originally posted by 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

Hi Mooly,

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

Nico

Mooly · 13th December 2008, 05:02 PM

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

Nico Ras · 13th December 2008, 05:26 PM

Quote:

Originally posted by Mooly
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.

11th December 2008, 10:10 PM	#1
YAKI diyAudio Member Join Date: Jun 2008	Yamaha cr-620 bass is lost in one channel 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

13th December 2008, 01:39 PM	#5
YAKI diyAudio Member Join Date: Jun 2008	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

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12th December 2008, 04:27 PM	#2
Mooly diyAudio Member Join Date: Sep 2007	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.

12th December 2008, 06:53 PM	#3
Nico Ras diyAudio Member Join Date: Nov 2005 Location: Amanzimtoti - East Coast of South Africa	Have you tried swapping the speakers, maybe the woofer coil is burned and it is stuck so you will only hear treble from it.

12th December 2008, 06:57 PM	#4
Nico Ras diyAudio Member Join Date: Nov 2005 Location: Amanzimtoti - East Coast of South Africa	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.

13th December 2008, 04:12 PM	#6
Mooly diyAudio Member Join Date: Sep 2007	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

13th December 2008, 05:02 PM	#8
Mooly diyAudio Member Join Date: Sep 2007	I was going to say check them out for bulges ( The caps of course ), but that could be taken the wrong way

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