In some TVs, the flyback transformer only generates about 6-10 kV AC which
is then boosted by a diode-capacitor ladder to the 18-30 kV needed for modern
color CRTs. The unit that does this is commonly called a tripler since it
multiplies the flyback output by about 3 times. Some TVs use a quadrupler
instead. However, many TVs generate the required HV directly with a winding
with the required number of turns inside the flyback transformer.
|NotTaR of Television Sets : What is a tripler?
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Triplers use a diode-capacitor ladder to multiply the 6-10 kV AC to 18-30 kV
DC. Many triplers are separate units, roughly cubical, and are not repairable.
Some triplers are built in to the flyback - it is probably cheaper to
manufacture the HV diodes and capacitors than to wind a direct high voltage
secondary on the flyback core. In either case, failure requires replacement
of the entire unit.
For external multipliers, the terminals are typically marked:
- IN - from flyback (6-10 kV AC).
- OUT - HV to CRT (20-30 kV DC).
- F - focus to CRT (2-8 kV).
- CTL - focus pot (many megohm to ground).
- G, GND, or COM - ground.
Symptoms of tripler failure are: lack of high voltage or insufficient high
voltage, arcing at focus protection spark gap, incorrect focus voltage, other
arcing, overload of HOT and/or flyback, or focus adjustment affecting
brightness (screen) setting or vice-versa. Where there is overloading, if you
disconnect the tripler and everything else comes back to life (obviously,
there will be no HV or picture), then it is very likely bad.