It's unlikely to be one of the LM339's if the left channel display is working - best bet is to compare your healthy left signal channel input network with the right. The .47uF zit red tantalums would be the first caps to go - 🙂 ... once you take the face-plate off 🙁
-Mal
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Check the voltage across those A42's. They are being used as zener
references, and might not be developing the voltage you want.
😎
Nevermind, that would affect both channels.
One of the 339's on that side might be bad, injecting current into
the node the - inputs of each 339 have in common. Try shorting that
node to ground.
references, and might not be developing the voltage you want.
😎
Nevermind, that would affect both channels.
One of the 339's on that side might be bad, injecting current into
the node the - inputs of each 339 have in common. Try shorting that
node to ground.
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Thanks Mal and Nelson for the help! I'll start with your suggestions and see if I can't get the amp back into proper fit.
Having solved the problem with the level meter with help here, a Beethoven string quartet was interrupted yesterday when the music in the left channel was suddenly replaced with a loud buzzing sound.
Switching inputs and outputs has isolated the problem in my CAS-2. My first suspicion was that a transistor had gone bad, inasmuch as they are, so far as I know, all original. A pal with a background in electronics, however, suggested that would normally cause fuses to blow (none have). Further, he thought the buzzing sounded like a 60-cycle hum which suggested to him a problem in filtering power supply noise out of the amplified signal.
Any suggestions here as to what might be the likely culprit?
Switching inputs and outputs has isolated the problem in my CAS-2. My first suspicion was that a transistor had gone bad, inasmuch as they are, so far as I know, all original. A pal with a background in electronics, however, suggested that would normally cause fuses to blow (none have). Further, he thought the buzzing sounded like a 60-cycle hum which suggested to him a problem in filtering power supply noise out of the amplified signal.
Any suggestions here as to what might be the likely culprit?
amp is old
what it needs is thorough examination by someone with proper expertise
not much luck with crystal ball
what it needs is thorough examination by someone with proper expertise
not much luck with crystal ball
If electroytics are old replace them.
Just good practice.
Then take it from there, eliminate the obvious causes first, they're a timebomb, makes sense to replace them.
Just good practice.
Then take it from there, eliminate the obvious causes first, they're a timebomb, makes sense to replace them.
Thanks 2 picoDumbs! All the electrolytic caps were replaced 6-7 years ago when I first acquired the amp. That would have been my first suspicion otherwise.
I suppose one of them could have gone bad in that time, however, and might still be worth checking.
I suppose one of them could have gone bad in that time, however, and might still be worth checking.
I was going to suggest you check power supply rectifiers (diodes) for one being open, but after you amazing attack on ZM, I am not going to help.
Please read the forum rules and stick to the topic. Off topic posts will be deleted.Dear Sir Nelson Pass,
I going to buy CAS2 amplifier for my Dali Grand speakers . Has it good bass controll and space ? I have e few nice amplifiers but I still look for something better 🙂 Is CAS better than Yamaha MX1, Harman Kardon HK990 , Rotel RB990 or Sherwood AM7040 ? I owned even Accuphase P500 but i was still not that I'm looking for 🙂
Best Regards
Bogdan
I going to buy CAS2 amplifier for my Dali Grand speakers . Has it good bass controll and space ? I have e few nice amplifiers but I still look for something better 🙂 Is CAS better than Yamaha MX1, Harman Kardon HK990 , Rotel RB990 or Sherwood AM7040 ? I owned even Accuphase P500 but i was still not that I'm looking for 🙂
Best Regards
Bogdan
mint specimen of CAS2 is better than amps you mentioned
however - do you have mint one to buy and how much wakoo your ears and brain are , only you can tell
however - do you have mint one to buy and how much wakoo your ears and brain are , only you can tell
Thank You, but maybe I should invest for 400A ? Is 400A much better than CAS2 ( for Grands off course ) ?
...... many commercially made amps would have to run for their money , against well made AB100
and , slapping different models of amps , asking which one is best ..... is childish
it depends - of room,speakers, SPL habits, source , taste of operator
and , slapping different models of amps , asking which one is best ..... is childish
it depends - of room,speakers, SPL habits, source , taste of operator