Yamaha Cr-1040 major issues Help

[Nik6667]

Hi all
I have just been given a cr-1040 free from a family friend who has owned this from new , no dust nothing has ever been replaced.
I turned it on, gets power the 3 uv meters light up the tuner lights across the top none of them go at all.
Have tried speaker ports with speakers making sure I connected before turning power on. 0 sound 1 had very faint sound but at near max volume.
The guy I got this from said to replace the 2 big capacitors.
And it should be fine? Does this sound odd I have read about the drivers but he assures me they are fine. Which I have 3 spare originals in case they ever do go (bonus) the fins got quite warm.
Also a few caps have yellow glue type stuff under them?

Thankyou

 

[clinic-audio]

Welcome on AK Nick6667 !

You will receive answer from CR1040 specialist soon , I personnally come back tonight

Do you hear the speaker relay making "click" 4 or 5 second after the first power ON ?

 

[chazix]

The guy I got this from said to replace the 2 big capacitors.

While he might have had some reason for suggesting this, it is very, very unlikely to cure a no-sound problem.

I second the suggestion to let us know if you hear the click. Also second the welcome to AK.

 

[Nik6667]

Hi guys no click at all. Thanks

 

[chazix]

no click

Then there is an internal problem that will need to be debugged. If you have a multimeter and are comfortable that you can work on opened-up, powered-up equipment while keeping yourself and the equipment safe, you can probably narrow down where the problem lies.

You'll want to get a service manual to start with. This one is kind of usable: https://elektrotanya.com/yamaha_cr-1040.pdf/download.html - except for the unfortunate page breaks. You could check the one from hifiengine.com, too, to see if you like it better.

The first debugging step I would suggest is to measure the DC voltage at test points TP1 and TP2 - see "Audio section adjustment" in the service manual to help locate those test points. The voltages should be very small if the power amplifier sections are working correctly. If they are very small, debugging will take a different direction. If the voltages are "kind of small", like 2V or less, you could try making the "DC offset voltage" adjustment in the service manual. If the voltage at one test point is large, then that power amplifier section has a problem. If the voltages at both test points are large, but about the same, then there is probably a power supply problem.

 

[Nik6667]

Both are quite high, when you say a power supply problem would that mean the caps? I'll upload a few photos

 

[chazix]

Both are quite high, when you say a power supply problem would that mean the caps?

If you mean the big caps, no, I still don't see any reason to suspect them, based on what's been discussed so far.

If both TPs read a high voltage, I would suspect the regulated power supply for the pre-drivers. The pre-drivers are the long 15-pin parts visible in your first picture. On either of those parts, pin 15 should have about +50V on it, and pin 6 should have about -50V. Be extremely careful measuring the voltages on those pins - a probe slip could easily be disastrous.

 

[Nik6667]

They are 15 (49) 6 (-50)

 

[chazix]

They are 15 (49) 6 (-50)

Oh dear - then, I'm kind of stuck at the moment. Do you remember what voltages you read on TP1 and TP2?

I probably won't pop in again today, but perhaps the next shift will come along with brighter ideas...

 

[chazix]

I haven't had any new ideas, but maybe I should say that I can only think of two ways that both TPs would show a large offset (when the power supply to the predrivers is normal):

• Separate failures in each of the power amp sections - seems relatively unlikely, but certainly possible
• Some sort of connection problem, like a broken trace, that screws up a ground path somewhere

It's probably worthwhile to check the bulk supply voltages - the voltages on the big caps - but even if one of the bulk supplies was missing, the power amps should still be able to maintain a low DC offset if they were working properly.

Unless a better idea comes along, I guess I'd suggest looking at the voltages on the inputs and outputs of the power packs. Those are the black boxes attached to the heat sink. Pins 1 and 10 (the outermost) are the inputs, and pins 3 and 8 are the outputs.

 

[Direct23]

Hi all
I have just been given a cr-1040 free from a family friend who has owned this from new , no dust nothing has ever been replaced.
I turned it on, gets power the 3 uv meters light up the tuner lights across the top none of them go at all.
Have tried speaker ports with speakers making sure I connected before turning power on. 0 sound 1 had very faint sound but at near max volume.
The guy I got this from said to replace the 2 big capacitors.
And it should be fine? Does this sound odd I have read about the drivers but he assures me they are fine. Which I have 3 spare originals in case they ever do go (bonus) the fins got quite warm.
Also a few caps have yellow glue type stuff under them?

Thankyou

Did you ever figure out what the problem was on the receiver? Dealing with kinda same issue at the moment thx.

 

[chazix]

Did you ever figure out what the problem was on the receiver? Dealing with kinda same issue at the moment thx.

Actually, the symptoms here differ significantly from the ones you've described in your new thread. I think you'll be best served by pursuing the new thread. The new thread seems to be converging on a theory that your receiver has a relatively simple case of a failed output pack, and I think that's very likely to be correct.