RCA P52937YX2, PTK195M26B
Symptom: tv would play perfectly for about 40 minutes and then begin pulling in vertically from bottom. After closing up about 8 inches there would be compression in the middle of the raster and raster would go off. Audio was still ok.
Looked like easy thermal intermittent to find. But nooooo. Cooling capacitors near the T-chip (U16201) and the T-chip itself would slowly bring the raster back. We used freeze spray on a Q-tip to try to pin it down and still got slow response. Changed T-chip (we used a socket) and several electrolytics in the area but did not help. Scoping the vertical out of the T-chip (pin15) showed the waveform decreasing.
Fix: Resolder several surface mounted components between the T-chip pins on pc side of board. Components were near pins 15 and 16. We think they included R14520 and possibly C14501 and C14503. We also resoldered the ground tabs between the T-chip pins. Touching those areas with freeze spray on a Q-tip gave immediate response.
Jeff Smith Smith TV Service