Sony TV with distorted picture
 

What would cause the picture in a Trinitron to squeeze up, leaving an inch of black at the bottom of the screen?

Re: Sony TV with distorted picture
 

Known as "frame cramp" I think.

One cause can be dried-up electrolytic capacitors in the frame output stage and/or the power supply, so check the supply voltage to the frame output stage.

Note that "Trinitron" can refer to thousands of models from the late 1960s to the early C21st, so a model number would be handy ;)

Re: Sony TV with distorted picture
 

As stated, dried up caps and depending on the model, dry joints on frame o/put IC.

Re: Sony TV with distorted picture
 

The capacitor responsible is usually right by the frame chip. Large-ish electrolytic. There are only a couple - change both and see to the dry joints and the set will be fine again.

Re: Sony TV with distorted picture
 

Seem to recall the value was a bit of an oddball one (these days anyway) in many Sony's. Was it 680uF. You could fit a 1000uF but it wasn't quite right linearity wise as I recall.

Re: Sony TV with distorted picture
 

Boot strap capacitors , used it increase voltage on frame output ic to speed up
fly back time so that next field could start at the right time. There is a diode from the line output transformer that might be o/c and in some sets a resistor
that might be high or o/c.
Regards Derrick

Re: Sony TV with distorted picture
 

Exactly - usually it's just the capacitor that fails. Usually the compression is noticed before the chip and feed components fail unless you had a very uncritical customer who ended up paying twice as much for the repair!
ISTR 680 or maybe 820uF?

Re: Sony TV with distorted picture
 

820uF, could well be Glyn. It must be over 20 years since I last did one.

Re: Sony TV with distorted picture
 

Awesome, thanks guys.