On Saturday, May 25, 2013 6:38:49 PM UTC-3, wrote:
The one thing about Sony Beta HIFIs is that they have a very zealous muting system. Another thing to remember is that each channel is processed separately, so usually any one bad component in the detectors should only affect one channel, unless it is a general failure of one of the ICs.



Find the muting circuit and disable it, you might find distorted audio which is rightly muted. (rightly muted means that between how it is decoded and the DBX expansion applied on playback, we are talking speaker blowing noise here) Unlike VHS, Beta uses the same heads for the AFM (HIFI) carriers. However the difference in frequencies means that just because you have a nice video carrier envelope, it does not necessarily follow that you have a perfect AFM carrier envelope.



You could have a severe dropout during vertical retrace time and it really depends on the monitor you use whether you will see any vertical sync problems. Most TVs had abandoned the countdown circuit but if it does use that, some units could stay in synch for quite a long time between periods of valid synch.



If you are using an LCD monitor, it is possible that the synch circuit is so good that it will lock onto noise, I do not know. Things have changed, there is no vertical oscillator anymore.



That's where I would go on this, and I did work on Betas, in fact I still have one that works. The envelope and the muting. If nothing pans out there hopefully you can get enough info on the chipset. Then the fun part, if you need an IC or a hybrid, finding one.



I have a small selection of OEM Sony parts from that era so if you find you need a proprieary part let me know. Even if I don't have it I know people in the business who might.

This VCR was only used for a few hours and was stored for nearly 30 years, so I doubt it's an issue with worn heads. But now that I think of it, anything that sat so long unused probably will need some caps.
I still use an old CRT TV with a countdown circuit, as I never really warmed up to LCD. I find older stuff like VHS tape looks terrible on LCD.
Thanks for the offer on parts, if I need anything I will let you know.