Eht Regulator - Sinclair Microvision MTV1 Service Manual

EHT regulator

Energy is stored in L1 during part of the line scan period and is then released into the various parts
of the circuitry suring line flyback time.
To put energy into the coil L1 during part of the scan period the current source T68 (2mA) is turned
on (T71 is off) and this current turns TR1 and TR2 on into saturation via the capacitor C2. After the
required amount of energy has been stored by L1 the transistor T71 turns on (due to a trigger pulse
from the line oscillator at the beginning of flyback). This removes the charge on C2 via D1 and turn
TR1 and TR2 off. The time period for which T68 is in its off state is determine by the charging state
of C1 which is in turn determined by the –45V rail setting of the EHT pot and current source T80.
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Sinclair MTV1 service manual V2.1