We went to a customer's house and looked at a late 90's Sony 31 inch set. The picture was blanking out and coming back on intermittently. When the picture came on, the CRT looked weak. Is this the auto kine bias circuit cutting off the CRT? We told her it was probably time for a new set...it just seems weird that a less than 10 yr old set already has a weak crt. They only watched the set several hours a day or less.

That's the classic symptom of a Sony set with a weak CRT. You can turn up the G2 to help make it last a little longer.

And BTW-- do NOT try to "hit" the CRT. if you do, it may look like it is better , BUT in a month or two, it will look WORSE thann it does now.

It probably has had a lot of hours on it.( I AGREE 10 years does NOT seem like long.. I have a '92 RCA ctc-169 32", with a great tube, I use daily, and a '94 RCA PTV, that looks like new.) When the IK ckt in the sony sets begins blankng the tube, 'cause it will not draw enough current, it is time to call for the compactor truck, to "fix" the set, once and for all!!

I once got about a year out of a Sony with a weak CRT by boosting the hearter voltage to about 8 v (you'll need a true RMS volt meter to measure this). I just added my own winding to the flyback and disconnected the built in one. I think it also had a H-K short. It ended up looking pretty good after that. I ended up selling it cheaply explaining that it will probably only last 6 months to a year at the most. They were happy and bought another set from me when it finally failed.

What does the picture look like when it's not blanked? If the CRT is weak, one color will be dim and blurry, but the others are probably fine. There are other failures that could cause these symptoms, but 9 times out of 10 it's the CRT.

I recall Sony had some bad picture tubes in the era that set was made. Not much better than Zenith. The Sonys now are pure junk. Check out e-opinions. It's kind of sad in the new set market that you can't even rely on Sony for quality anymore. Also, I think I read they're not even made in Japan due to cost. I'm pretty sure they're made in China like everthing else...

The standby light was initally blinking when set powered up from cold, then is came on solid. The audio was on consistently, just the picture was blanking out. The picture was somewhat fuzzy and the color balance was off like one of the crt guns was weak. It just had the picture characteristics of what I have seen on weak crt's.
I think a new set is their best option, we really don't want to haul that set and charge for the labor of rejuvinating the crt just to have it break down after a while. They were asking what the best type of new set is but it was hard for me to say! In a modern set I'm not really sure what's best.
The customers said they bought that set cause they thought Sony was high quality (which it was in the 70's and 80's).