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Yamaha CA-1010 meter swing when switch on/off

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pht714

Active Member
Hello,

recently acquired a very clean Yamaha CA-1010.
the internal is "virgin" but a bit of dusty. No crackling, hiss, pop noise that I can hear of but decided to air spray, deoxit, lub ... then finally adjust idle current for both A and Normal operation modes.

all look good. (will upload photos tonight).

question is, when power on/off (doesn't matter if it is in A class or Normal class)
The needles of both channels swing to about 40% then come to zero. Is this normal or there is a potential problem somewhere?

Thanks for the input.
 
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well at least they're swinging together ha! i have no idea but someone will come along shortly to help. glad you got it and barring some major issue i'd say you did ok.
 
here are some internal photos.
can someone shred some light where to begin troubleshoot this bug.

thanks.
 

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pht714 said:
The needles of both channels swing to about 40% then come to zero. Is this normal or there is a potential problem somewhere?
Click to expand...
With my CA-1010 it's the same. I think it's caused by the settling period of the transistors in the meter PCB.

Nice pictures btw! :thmbsp:
 
I hope this is common/standard among CA-1010. I hate to think that this is a problem and keep chasing my tail fixing the un-broken issue.
Any CA-1010 out there, please confirm your unit if you can.

Thanks.
 
New discovery,
The power transformer humming noise is very noticeable.
Speaker switch is off and volume is at zero, the noise is heard by just standing close to the amp. It wasnt like this before.
 
pht714 said:
New discovery,
The power transformer humming noise is very noticeable.
Click to expand...

Recheck the bias adjustment; maybe things have drifted since you set them. If they're the original pots they're not the greatest, especially after 30 years of service.

I don't have a CA-1010 but if there's a protection circuit involved, the meter swing on power up is likely quite normal. Assuming there is one, the meters should be back to their resting position by the time you hear the protection relay click. :thmbsp:
 
I've checked both normal and class A twice already and they are in 25mV and 280mV respectively. Yes, the trim pots are original. The unit is very clean. And yes, the VU swing before any relay click and come to rest position just about the time the relay clicked. It just weird that my CR 2020 doesn't do it.

Btw, this ca is very hot in both normal or Class A after 15 minute or so and I love the way it looks and sound :d:d
 
pht714 said:
Hello,

recently acquired a very clean Yamaha CA-1010.
the internal is "virgin" but a bit of dusty. No crackling, hiss, pop noise that I can hear of but decided to air spray, deoxit, lub ... then finally adjust idle current for both A and Normal operation modes.

all look good. (will upload photos tonight).

question is, when power on/off (doesn't matter if it is in A class or Normal class)
The needles of both channels swing to about 40% then come to zero. Is this normal or there is a potential problem somewhere?

Thanks for the input.
Click to expand...

Mine does same - meter jump is normal. And also on CA810
 
Thanks gents & ladies!
I'll put that swinging VU to rest. Now my next test will be identify all caps and try to recap it. But first, I need to build my audio rack. I got a few pieces and they have been laying all around the bedroom. The wife start to complain ....
 
I believe this is caused by the initial DC at turn on. Thats why some units have protection circuitry to prevent this DC from reaching the speakers. My SX-580 did it too.
 
ouimetnick said:
I believe this is caused by the initial DC at turn on. Thats why some units have protection circuitry to prevent this DC from reaching the speakers. My SX-580 did it too.
Click to expand...
I don't think that is correct, when the Meter Switch is in the SP OUT position, the meters probe the voltages on the speaker-side of the relay, so it should not sense the initial DC of the amp PCBs. That's why I made my previous comment,
pradigmshift said:
I think it's caused by the settling period of the transistors in the meter PCB.
Click to expand...
R423 / R424 (470 KOhms) prevent that this transient voltage can generate large enough currents to the speakers to hear it.
 
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