CA-1010: don't you hate when someone brings you a ...

nerdorama

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broken piece of audio gear and just assumes you are accepting donations today? A couple of years ago I sold a Yamaha integrated, much newer than this, to a fellow that wanted it for his shop. His amp had died and he just wanted something else that worked. I had forgotten about the details of this exchange other than I now remember telling not to throw it away as it was a nice amp. He is a cabinet maker and I kept his contact info because I thought I would be remodeling my kitchen sometime soon. So, I called him about a week ago and he came yesterday to talk over my project AND he brought the old Yamaha with him. It was a bit ratty with a few chips to the veneer and some sort of smutz spilled on the top rear of the case.

Anyway he said one channel was out, so I assumed it would be a power amp section. I wiped the case with a damp rag and the smutz seemed to soften so a taping knife scraped it right off. There is a bit of a darkened/stained area but not so bad. I had some hope that maybe the amp/preamp bridging switch or another control might be the culprit for the "no signal" in one channel. So far I've found that the power amp works fine so I guess I'm looking in the preamp section. I still hope it will just be a dirty control. Might also be a power supply issue but I assume this would be common to both channels.

I'll clean all the controls of course, but anyone have any other common issues with the preamp section to recommend? As with so many things like this, I don't need it (already have one actually) but how can you just let something like this go without attempting to make it right. I offered to fix it for him but he said he didn't need it. I should just turn it around and move it along, but I have a hard time doing that. I want to fix every piece of audio gear that lands in my lap. It's sick. I'm really a tube guy but I love to see things get fixed and remain useful and enjoyable.

Thanks for listening,
John
 
Sounds like a nice problem to have and good karma to boot. It certainly is a nice looking integrated amplifier.
 
Drop it off to me and I'll save it.


Check the power supply for proper voltages, working fuses.
 
Thanks for the comments. Obviously I'm not at all upset about this but it was fun to write up. I listened to the power amp section for a couple of hours yesterday. It was very nice. One of these days I'll crack into it and do some signal tracing and voltage checks and see where it leads.

I just wish someone in the past of this amp hadn't put their driver's license on the front panel. Sheesh, some people's children.
John
 
Did a little digging in the tone board section tonight. I've got signal all the way through to just before the mute switch and muting relay. It's a relief since it means all the amplifying electronics appear to be ok. I'll give the mute switch a cleaning tomorrow and check the relay. Almost there I think. I'm glad it didn't end in the dump.
 
I just wish someone in the past of this amp hadn't put their driver's license on the front panel. Sheesh, some people's children.
John

Quite the theft deterrent 35-40 years ago. I would bet campus cops had a hand in it.
 
So my final problem is a bad reed relay. It's mounted next to the volume pot, a Fujitsu RL-6442-H132, and seems to one of the muting relays. This is 12VDC coil and DPST. A preliminary look around the web makes it appear that this is a bit hard to replace. Any advice or suggestions welcome before I do something offbeat. I suppose I could just bridge the contact connections on the PCB with jumper wires for now. Not sure if I'd get some turn on/off noises but at least the amp would work.

Thanks,
John
 
Got any parts units laying around? A C-4 has 2 of them I believe. Otherwise your going to have to get creative with whats currently available.
 
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Watching with interest.
I have a 2010 showing up by me in a day or so. Minty cosmetics. No sound. Maybe I'm being too hopeful, but sounds like I might have the same issue. Mine is going to visit avionic sometime in the not too distant future so I'm not concerned. It would be nice for it to work before it goes out for an update. Maybe get some kind of before, after feel
 
Watching with interest.
I have a 2010 showing up by me in a day or so. Minty cosmetics. No sound. Maybe I'm being too hopeful, but sounds like I might have the same issue. Mine is going to visit avionic sometime in the not too distant future so I'm not concerned. It would be nice for it to work before it goes out for an update. Maybe get some kind of before, after feel

FWIW, I had one show up with no sound. It was bad fuses.

Check them with a meter.
 
All fuses are good. When I connected a jumper across what I believed to be a bad reed contact in the relay I got sound from the amp. The power amp works ok and the preamp had signal up to the upstream side of the relay. I ordered a relay on the big auction last night that looks like I may be able to adapt to this purpose. Now that the relay is removed from the amp, I don't get continuity on the coil so maybe it was weak and not closing the reeds completely. The solder joints on the iffy contact looked like they had been touched in the past and were poorly soldered so it made me suspect an issue. If the new relay doesn't work I might try Avionics solution of using a DIP relay and socket.
Thanks for the suggestions.
John
 
Just out of curiosity, I've seen threads where some have modified readily available relays to mimic discontinued ones. Would you have a spec ( Pinout) on that?

FWIW, I had one show up with no sound. It was bad fuses.

Check them with a meter.

Thanks for the info

I'll have to look into that. Based on its physical condition, I'd bet it had a very easy life. Again, not in my hands yet. I know its lights up at power on so at least some of the fuses are good. I don't know if that's a good thing or a bad thing yet.

I'm a little squeamish digging into SS stuff.
Tubes you just see my feet dangling out.
That just means I'm not afraid, not that I'm good:D
 
Just out of curiosity, I've seen threads where some have modified readily available relays to mimic discontinued ones. Would you have a spec ( Pinout) on that?



Thanks for the info

I'll have to look into that. Based on its physical condition, I'd bet it had a very easy life. Again, not in my hands yet. I know its lights up at power on so at least some of the fuses are good. I don't know if that's a good thing or a bad thing yet.

I'm a little squeamish digging into SS stuff.
Tubes you just see my feet dangling out.
That just means I'm not afraid, not that I'm good:D

I don't get a lot of tube to work on and I always have to mentally "change gears" when I do.
Its the same, but different.
 
All fuses are good. When I connected a jumper across what I believed to be a bad reed contact in the relay I got sound from the amp. The power amp works ok and the preamp had signal up to the upstream side of the relay. I ordered a relay on the big auction last night that looks like I may be able to adapt to this purpose. Now that the relay is removed from the amp, I don't get continuity on the coil so maybe it was weak and not closing the reeds completely. The solder joints on the iffy contact looked like they had been touched in the past and were poorly soldered so it made me suspect an issue. If the new relay doesn't work I might try Avionics solution of using a DIP relay and socket.
Thanks for the suggestions.
John
Are you getting the 12vdc to the relay coil ?
 
Yes, but it"seems closers to 10V. I had audio in one channel but not the other so I assumed one contact was bad. A jumper across bad terminal while that amp was on brought the other channel to life.
 
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