Vertical IC500(TDA9302H) is shorted rpl. Also replace c557(100uf/35v)for safety. D409(BYD33J)is a high freq diode, use nte552.

Be sure and observe polarity on the diode and the filter. D409 creates -13v for the vertical ic.

Good luck,

pw

Hi, Pee_Wee,

Thanks for your help! As you suggested, I replaced D409 with NTE552 and IC500 with NTE1788, as well as C557 (220uF/35V on my model). Now the TV is displaying only the top half (no distortion); the bottom half of the screen is completely blank. I checked the rectified output from D409 and D445, and they are -13V and 13V respectively. I've left the TV on for over an hour and no blown components. Everything is fine except that the bottom half of the screen is blank. When I turn off the TV, for a split second I can see a full vertical deflection, so aparently the yoke is good.

Can you think of anything wrong?

thanks,
-- John

Make sure that the (+)13 on pin 2 & (-)13 on pin 4. Check the voltages on the ic pins, not just on the diodes.

Check soldering on ic500.

Make sure that c557 is correct polarity.

Check d550. It can be checked in circuit, w/diode ck. Be sure and measure BOTH directions, should be high/low.

Slim possibility that the nte1788 won't work properly..... for TDA9302H.

pw

I did check pin2 and pin4 of IC500 when I measured +13 and -13V. Also I'm darn sure of the polarity of all electro-caps and diodes. I've tried to swap the three diodes (D409, D445 and D550) and the results are the same -- only top half of the screen. I suspect that the input to IC500 is clamped at ground, but I don't have an oscilloscope with me now so I can't tell. Using a voltage meter, I saw -0.35V RMS on pin1 of IC500 and +0.35V RMS on pin7.

Does anyone have a service manual or schematic of the vertical deflection circuit?

thanks,
-- John