Repair of a Cyrus 3 with volume control issues.

Here is a Cyrus 3 Integrated Amplifier that had issues on one channel where there were some DC pops at certain volume increments. We look at the circuitry involved and trace the problem down to a leaky analog switch.

[@geronimostade8279]

Strange how people come across youtube channels.
First before anything -> i dont know your name but i really enjoy watching your vids! Thats great stuff made by an intelligent guy! I hope you get much appreciation for your vids and i tell this from the bottom of my heart. Keep this up!!!! You got a very serious follower here!
Then... Why i came here was acutally that just the other day one cyrus III came in for repair... First time for me after 30 years of maintenance, repair and rebuild of obsolete equippment. And before i even lifted one screw i thought to see what others have in terms of common failures.
The particular Cyrus III that i have here has several issues... One is that it grilled 2 sets of expensive speakers whilst in standby, because of a leaky BC856 in the LTP Stage. Poor desing acutally :D Because it doesnt cut out the speakers whilst in standby nor does it lift the voltage from the output stage...
One other issue is that it randomly switches whatever... I mean literally whatever. It changes Inputs, volumes and when it does that, the power led becomes orange.
Also weird is that if in this state, regardless of the input (L or R) the signal gets through to both output channels. When only attaching a speaker or load to the right channel and the input to the right channel everything sounds normal. Strange is that if i attach a signal to the left channel it passes through to the right channel. Its not as loud as the right input but quite above 70 percent of volume... Odd thing.
Another issue this unit has is that when the Volume leds reach 50 Percent and the input singnal is sine wave 1Khz, it goes into random oscillation on both channels.
I have gunshotted this guy with capacitors of course, not because one was bad... In fact they were all good (more or less) just because they cost next to nothing.
If you have any idea to these issues, ill be glad to follow your advise.
Thanks alot man! If you will never react to my request, dont worry, you have a follower anyways :)
One last thing i have noticed is possibly a common behavior or better said normal. It appears to me that there is an audible difference between volumes in terms of frequency response.
I would need to check this against FFT and noise. But its like that when volume gets higher, there is a slight change in treble response. I cant tell off hand if thats getting lower or higher because i was troubleshooting another part - need to revisit this. Have you ever done measurements on that or ever heard of it?
Cheers Geronimo

[@myalbatech]

Thanks for your comments. You could suspect all those cmos logic devices for your random behaviour. The other one is the microcontroller. These tend to fail in odd ways and this is generally terminal. Same situation as shown in my Cyrus Power video.

[@itisjustacomment]

Any common issues with the Cyrus Integrated amplifier and where would I find such issues and circuit diagram on line please. Would be a big help thanks.

[@itisjustacomment]

Just subbed , did 3 years for electrics in college in 1992 and recently buying a Cyrus 8 for £100 buyer says bought it as spares but they fixed it and its fully working.
Well let's wait and see, its coming tomorrow.
Quick injury where would I got circuit diagram for cyrus 8 Integrated amps .
Seems you channel is best of both words for me .
Thank martin from Leeds:)

[@turntableman100]

Do you repeat cd player

[@turntableman100]

Hi how much is the service with Cyrus

[@myalbatech]

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[@frankgeeraerts6243]

I had a Cyrus Two first edition .........to me this generation looks like overpriced junk.