Quasar Projection TV and AN5521 Vertical Problems
 

I have a Quasar Projection TV with a very unusal vertical problem.
This unit uses an AN5521 vertical IC. I have checked ALL of the
electrolytic capacitors for value and ESR all check o kay. The vertical
problem I have is that this unit will have full raster and no vertical
foldover....after 20 minutes this unit will still have a picture or
raster but with a faint line which is horizontal. Someone told me that
this may be caused by oscillation of the vertical IC ( AN5521 ). I was
also told that this could be fixed by putting a 560 PF capacitor on
pins 2 & 5 of the vertical IC and if this did not work the try a 1, 000
PF capacitor. I am confused because this was to fix only vertical
instability. And the chassis that were affected bu this problem a
AMEDP 807, YAMEDP 807, AEDP 807, and YALEDP 807.

Since Matsu****a made this chassis, the Panasonic models affected
by this problem a

PTP - 4586, PTP - 4588 , PTP - 5189.

The measurements on the pins of the AN5521 read as follows:
Pin # 1................ Ground
Pin # 2............... Output 16.5 v DC and about 54 v Peak to Peak
Vertical output
Pin # 3.............. Boost about 29.8 v DC.
Pin # 4.............. Input 0.7 v DC and about 0.8 v Peak to Peak
input.
Pin # 5.............. Feed Back Pin reads about (-) minus 0.2 volts
Pin # 6.............. Amp pin .... 2.56 v DC
Pin # 7............. Vcc about 28 volts DC

This unit has no convergence problems noted with a cross hatch
patteren. Could this be in the Jungle IC or Processor IC. Or else
where? Any ideas will be greatly appriciated.

Pat Green
Cowboy's Appliances
Beaumont, Texas