1st things first, as I always say....
1. Check your soldering around the vertical section. Most sets have defects in thier soldering of the components under the board, with time. Especially true of RCA and Zenith sets, but all makes are not exempt! Again, check this first and fix as necessary.
2. Look for one or more electrolytic capacitors in the vertical section, maybe around 100uf 35v ,1uf 50v or a 220uf 35v or similar values. Change these, even if they look physically ok., observing the polarity of each. Most of the repairs I do involve these components. They fail with time and change value. Higher value caps , like 1000uf, 2200uf, etc., are usually not the reason for vertical troubles, just to note.
Further steps, if needed:
3. You might even have a shorted or open diode next to the vertical chip. It is usually black with a gray stripe on it. Be sure to replace it with the same polarity as the old one- the "stripe: denotes the cathode side of the diode. Do not get it backwards, (important!) - follow the "arrow" symbol on the board... you can check the diode with most multimeters. It should read in only one direction as a rule of thumb. If it's shorted, you'll get a reading in both directions, and if open, no reading of course. You can use most generic, 1 amp diodes (not zeners) to replace it, I found.
4. Your vertical chip itself may be bad, but you'll usually get a line straight across if it is. If after doing the above with no result, you may want to change it.
on Jan 28, 2008