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Expanded Internals
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(Expanded Internals) |
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==Internals== | ===Internals=== | ||
==Vertical== | |||
The probe input first goes through compensated attenuators and then into one gate of Q18, a dual JFET. | |||
The drains of the dual JFET drive the inputs of dual output amplifier IC U25, part number [[155-0057-00]]. | |||
U25 drives one section of dual output amplifier U105 [[155-0047-00]] which drives CRT V-plates via output transistors Q110/Q107 | |||
Triggering is done using | ==Horizontal== | ||
Triggering is done using U65 [[155-0048-01]], which contains external horizontal amplifier, trigger and sweep generator. | |||
Output of U65 drives the second section of dual output amplifier IC U25 [[155-0057-00]] who's output is fed to the H-plates via output transistors Q119/Q122. | |||
U65 is mounted on the input board. Unblanking signal from U65 is driven to CRT via Q134 | |||
==Power Supply== | |||
Tek 211 can be operated from line power or internal Ni-Cd battery. Line power is also used for charging the batteries. | |||
Internally the unit uses a DC-DC converter to generate the required voltages from battery or line, using Q242, 2459 and T250. | |||
DC-DC converter generates the +5.6, -5.6 and +65 used in the unit. | |||
-1000V for CRT is generated using voltage multiplier. | |||
Instead of transformer, capacitive divider is used to step-down down the line voltage. | |||
C210 is the capacitor for providing charging voltage and C212 provide voltage for line operation. | |||
Value of these capacitors needs to be adjusted based on operating line frequency and voltage. | |||
Manual suggests recommended values of these capacitors for common line voltages. | |||
Input AC must be sinusoidal to offer the correct reactance to step-down the line voltage. | |||
Like other instruments of the era there are no filter capacitors in the power supply, rather the battery is used as the filter capacitor. | |||
Hence disconnecting battery can affect the unit's operation. | |||
==Background== | ==Background== | ||