Alberto:
I would check the high-voltage transformer(flyback) next.
My flyback test is as follows:
1. Measure the resistance from the HV anode to ground. It should
read open circuit. Any resistance ususally means it is bad.
2. Check the capactance from anode to ground. It should read about 2.5
to 3 nano-farads. I usually assume 1.5 to 5 is OK.
3. Check the primary winding with a flyback ring tester.

Also
4. Check any electrolytic capactors near the horizontal driver transformer.
5. Check for any shorted FET's or bad electrolytic capacitors in the
circuit that supplies the B+ voltage to the flyback (and HOT).
Note: these tests will not always find a bad flyback.

Hope this helps...
John