Sinclair MTV1 service manual V2.1 Page 21 of 39
Frame scan
During frame flyback transistors T52 and T50 are turned on. This causes the transistors TR1 and
TR2 to turn on and eventually saturate.
During frame scan, the transistors T52 and T50 turn off and the collectors of TR1 and TR2 rise
linearly towards their respective 300V HTs. Their scan amplitudes are dictated by the rate at which
the 470pF capacitors are charged. This current is due to the 1.2V across TR1 and TR2 V
BE
s and
the value of the amplitude pot.