I bought a CR-820 from eBay a while back and about a month ago, I got around to cleaning it up and giving it a De-Oxit treatment. That went well and it has worked great for the last month or so. The other day I go to turn it on and it lights up but there's no protection relay click after a few seconds like usual and no sound comes out from the speaker or headphone outputs from any of the inputs. I opened it up and none of the fuses are blown and nothing visually looks damaged. Anyone have any ideas about what the problem could be? It's in great condition so I'd like to get it working again. Thanks
No Sound From Yamaha CR-820
- Thread starter jjwl89
- Start date
lixaudio
Active Member
Hi,
I had the same problem with my CR620.
There is a transistor on a small silver heatsink close to protection relay. I think it drops the voltage for the coil and because of the heat it looses the connections with pcb. No current to relay, no clicks, no sound. Check that first, put a bigger heatsink and try to glue it on a pcb with silicone or epoxi.
LIX
I had the same problem with my CR620.
There is a transistor on a small silver heatsink close to protection relay. I think it drops the voltage for the coil and because of the heat it looses the connections with pcb. No current to relay, no clicks, no sound. Check that first, put a bigger heatsink and try to glue it on a pcb with silicone or epoxi.
LIX
dancingbear
New Member
Hi there,
This is my first post here - please excuse my lack of knowledge. I have been lurking for a while, picking up what I can, but it would seem, not enough!
I have a gorgeous CR1020 - apart from a couple of bulbs, works perfectly. Recently a CR820 appeared for sale 5 miles away, described as "not working". Having read this thread I figured for £5 or so, I might have a go at fixing it - then I would have 2! The foolishness of this is obvious - when I am into double figures on amps and tuners and receivers - and I have no technical knowledge.
Anyway - I picked it up - it looks beautiful, and powers up OK, but no sound. So I begin looking for the problem described above - and can see nothing physically wrong. What do I do now? Abandon? (take the bulbs and put them in my CR1020 if they fit!) Find a technician? Or could I learn to do this myself? Do I need anything apart from a screwdriver and solder? I fear I may be out of my depth.
All help gratefully received - especially from anyone who lives in the Hertford, UK area!!!
This is my first post here - please excuse my lack of knowledge. I have been lurking for a while, picking up what I can, but it would seem, not enough!
I have a gorgeous CR1020 - apart from a couple of bulbs, works perfectly. Recently a CR820 appeared for sale 5 miles away, described as "not working". Having read this thread I figured for £5 or so, I might have a go at fixing it - then I would have 2! The foolishness of this is obvious - when I am into double figures on amps and tuners and receivers - and I have no technical knowledge.
Anyway - I picked it up - it looks beautiful, and powers up OK, but no sound. So I begin looking for the problem described above - and can see nothing physically wrong. What do I do now? Abandon? (take the bulbs and put them in my CR1020 if they fit!) Find a technician? Or could I learn to do this myself? Do I need anything apart from a screwdriver and solder? I fear I may be out of my depth.
All help gratefully received - especially from anyone who lives in the Hertford, UK area!!!
merrylander
AK Member
Ok guys, if you do not have a multimeter you are at a definite disadvanrage, that said here we go:
! Plug it in and switch the power on.
Does the power LED light?
If so the main fuse is good. if not either blown fuse or transformer
Do the dial lamps light?
The low voltage is good (need this for the preotection relay also.
Do you hear a soft click about 5 - 10 seconds after the power goes on?
If so then it is probably a dirty switch somewhere
If not this is where you need a meter to see if the outputs are shot.
That is the basic starting point, after that you can Deoxil switches and controls and see what happens.
Of course it could come out of protection but still have no sound. On many Yammies the Muting switch and the coupler switch (in back if it has one) are possible suspects. Beyond simple dirty contacts it could have a bad transistors somewhere and this is where a signal tracer pays for itself in time and lost hair.
! Plug it in and switch the power on.
Does the power LED light?
If so the main fuse is good. if not either blown fuse or transformer
Do the dial lamps light?
The low voltage is good (need this for the preotection relay also.
Do you hear a soft click about 5 - 10 seconds after the power goes on?
If so then it is probably a dirty switch somewhere
If not this is where you need a meter to see if the outputs are shot.
That is the basic starting point, after that you can Deoxil switches and controls and see what happens.
Of course it could come out of protection but still have no sound. On many Yammies the Muting switch and the coupler switch (in back if it has one) are possible suspects. Beyond simple dirty contacts it could have a bad transistors somewhere and this is where a signal tracer pays for itself in time and lost hair.
dancingbear
New Member
Thanks. I get to the "lights on, nobodies home" stage. I will try again, but I am pretty sure there is no soft click. So it is likely I need to get a multimeter?!
Simon
Simon
dancingbear
New Member
Well, I have spent the afternoon fiddling around inside this thing, and found a few things out, but am also slightly puzzled by an invisible transistor.
It is getting radio reception, and when I move the relay switch (under the plastic cover) there is sound from one channel (only a hum from the other).
According to the circuit diagram the transistor that was likely to fail a "2SD234" is number TR806 - but I can't find this one. I assume it is in the same area. Can anyone point me in the right direction here?
Many thanks,
Simon
***EDIT - just found the B*gger - now for testing it!***
It is getting radio reception, and when I move the relay switch (under the plastic cover) there is sound from one channel (only a hum from the other).
According to the circuit diagram the transistor that was likely to fail a "2SD234" is number TR806 - but I can't find this one. I assume it is in the same area. Can anyone point me in the right direction here?
Many thanks,
Simon
***EDIT - just found the B*gger - now for testing it!***
Last edited:
merrylander
AK Member
The 2SD234 is the one near the power transformer with the U shape aluminium heatsink.
dancingbear
New Member
Many thanks, Merrylander. I found the 2SD234, and have removed it. I have ordered a replacement - fingers crossed!
If this works, is there anything else you would advise could be easily checked, before I put it into service?
Many thanks
If this works, is there anything else you would advise could be easily checked, before I put it into service?
Many thanks
merrylander
AK Member
Somewhere here on AK is the proceedure for adjusting the idle current.
Instead of starting a new thread, I figured this one would do since I have the same problem.
• When I test the CR-820 on the dim bulb the bulb doesn't light at all. Tested the DBT with another receiver and it works fine.
• Rolled the dice and powered the 820 on w/o DBT and the lights & meters work, but no relay click or sound.
• Re-soldered the pins of TR806 (I believe), the transistor with the heat sink near the two 1A/250V fuses, but no change.
• Pulled TR806 (?) and it tested good, but my Peak tester has only called one transistor bad (short) in its career, so I'd like to replace the transistor. Trying to find a sub.
Any thoughts.
• When I test the CR-820 on the dim bulb the bulb doesn't light at all. Tested the DBT with another receiver and it works fine.
• Rolled the dice and powered the 820 on w/o DBT and the lights & meters work, but no relay click or sound.
• Re-soldered the pins of TR806 (I believe), the transistor with the heat sink near the two 1A/250V fuses, but no change.
• Pulled TR806 (?) and it tested good, but my Peak tester has only called one transistor bad (short) in its career, so I'd like to replace the transistor. Trying to find a sub.
Any thoughts.
Need to verify if there is any DC voltage present at the amplifier outputs somewhere before the protect relay.
Sounds good, but the pointer & meter lamps are out, at least one of them is dead.
