Yamaha CR-2040 Troubleshooting Help

[Rick F]

Hello! I recently came into possession of a CR-2040 due to it being in the garage of a house we just bought. Having an (admittedly rusty) EE background I thought it might be a cool project to get back up and running. The behavior I'm seeing is that the unit seems to power up normally (you can hear the click of a relay after a second) but I'm not getting any sound on the right channel and very low volume on the left channel. This seems to be consistent for both A and B speaker outputs. Also, the left level meter does not move but the right meter behaves like one might expect when there's audio. I'm currently using the tuner as the audio input since I'm still scrounging for something that has RCA audio out. I've got the service manual and my next steps are going to be checking voltages on transistors. I wanted to check here though if anyone had any obvious first things to examine when working on one of these units.

From a quick inspection I would suspect the unit's been re-capped and there's a resistor mod of some sort on the tuner board. I don't see any obvious cold solder joints or shorts on the back of the PCB's.

Any guidance would be appreciated! Also, I'm not an audiophile so I apologize in advance if I ask some stupid questions.

Thanks,
Rick

 

[clinic-audio]

Hello Rick

Welcome on AK

The CR2040 is a very goof piece !

Do you have the service manual ?

 

[mr_light]

Manuals can be found here. May need to register, free.

https://www.hifiengine.com/manual_library/yamaha/cr-2040.shtml

 

[Rick F]

Hello Rick

Welcome on AK

The CR2040 is a very goof piece !

Do you have the service manual ?

Hey! Yes I do have a copy of it and was going to be double checking the expected output voltages in the power and amp boards. I was hoping there might be some common culprits for the symptoms I described.

Thanks,
Rick

 

[avionic]

Hello! I recently came into possession of a CR-2040 due to it being in the garage of a house we just bought. Having an (admittedly rusty) EE background I thought it might be a cool project to get back up and running. The behavior I'm seeing is that the unit seems to power up normally (you can hear the click of a relay after a second) but I'm not getting any sound on the right channel and very low volume on the left channel. This seems to be consistent for both A and B speaker outputs. Also, the left level meter does not move but the right meter behaves like one might expect when there's audio. I'm currently using the tuner as the audio input since I'm still scrounging for something that has RCA audio out. I've got the service manual and my next steps are going to be checking voltages on transistors. I wanted to check here though if anyone had any obvious first things to examine when working on one of these units.

From a quick inspection I would suspect the unit's been re-capped and there's a resistor mod of some sort on the tuner board. I don't see any obvious cold solder joints or shorts on the back of the PCB's.


Any guidance would be appreciated! Also, I'm not an audiophile so I apologize in advance if I ask some stupid questions.

Thanks,
Rick

Welcome aboard Rick... First investigate the possibility of a dirty switch or control..Input Select switch would be a good place to start.

Dave

 

[Rick F]

Welcome aboard Rick... First investigate the possibility of a dirty switch or control..Input Select switch would be a good place to start.

Dave

Hey thanks for the info. I picked up some contact cleaner from a guitar shop and will try it out tomorrow.

Rick

 

[Rick F]

Welcome aboard Rick... First investigate the possibility of a dirty switch or control..Input Select switch would be a good place to start.

Dave

Hey Dave, you were right on with this direction. I cleaned the select switches and the pots and sure enough it started to work! Any other areas that would be good to give some attention since I have it cracked open?

Rick

 

[avionic]

If one or two switches were dirty, they are all just as dirty. Which is to be expected with a unit this old.Usually I remove the switches from the unit . Disassemble them and thoroughly clean the actual switch contacts.