Theory of Operation
WFM 601 - Service Manual
3–19
frequency response characteristics of the CRT are compensated for by a network
between the VOUT+ and VOUT– terminals of U55.
Q10 and Q16 are power transistors that drive the CRT deflection plates. A
sample of the horizontal output voltage is fed into the emitters of the transistors
to compensate for CRT orthogonality error. U57A and B are noninverting buffer
amplifiers driving U64B, which converts the differential signals to a single
ended voltage that is applied through R168, the Y Align adjustment.
Diagram 13 Horizontal
The sweep generators are nearly identical buffered integrators. They are started
by either the line or field sweep speed signal from a DAC shown on Diagram 17.
For purposes of simplicity we will discuss only the Field Sweep generator.
The FLD SWP SPD signal from the DAC is filtered by an input filter with a 0.1
second time constant, R83 and C55. U39A is a buffer to drive U62A, an
integrator. C101 is the integrator capacitance. When retrace occurs, U63B
closes and discharges C101. When the FLD SWP SPD goes high, and U63B is
open, the output of U62A ramps up and provides the vertical sweep to the
Vertical Input Switch (Picture mode) and the Horizontal Signal Multiplexer.
The Horizontal Signal input selection consists of dual in-line package (DIP)
switch segments (U59, U63, U70, and U94) and an 3-to-8 line decoder (U60).
The decoder is controlled by three synchronous outputs from the Line Rate
Controller (Diagram 15). It is permanently enabled (pins 4, 5, and 6) so that any
change in state of the control lines (pins 1, 2, and 3) will pull one of the six
outputs (Y0–Y6) low and close the appropriate DIP switch segment.
The Horizontal Amplifier, U56, contains two independent amplifiers. The
external gain-controlled Auxiliary Amplifier is used as a single ended luminance
amplifier. The output of the Luminance Filter Amplifier (Diagram 11) is input to
the + input of the Aux amplifier. Its gain is controlled by the PIX CONTRAST
level from a DAC shown on Diagram 17. The single ended output drives an
inverting operational amplifier, U47B. The minus input of U47B is a summing
junction for the PIX BK LVL (black level) and the luminance from U56. The
output of U47B is the picture monitor intensity signal to the Z-Axis control
circuit (Diagram 19).
The main Horizontal Amplifier, which has inputs for horizontal signals and the
readout signal, converts the single ended input from the Horizontal MUX to a
differential output. In addition, it amplifies the differential input of the readout
Vertical Deflection
Sweep Generators
Horizontal Signal MUX
Horizontal Amplifier
Summary of Contents for WFM601
Page 4: ...The WFM601 Serial Digital Component Monitor...
Page 10: ...Contents iv WFM 601 Service Manual Revised Nov 1994...
Page 14: ...Contents viii WFM 601 Service Manual Revised Nov 1994...
Page 19: ......
Page 32: ......
Page 50: ...Installation 2 18 WFM 601 Service Manual...
Page 57: ......
Page 87: ...Theory of Operation 3 30 WFM 601 Service Manual...
Page 88: ......
Page 110: ...Performance Verification 4 22 WFM 601 Service Manual...
Page 111: ......
Page 132: ......
Page 168: ...Maintenance 6 36 WFM 601 Service Manual...
Page 169: ......
Page 175: ...Options 7 6 WFM 601 Service Manual...
Page 176: ......
Page 177: ......
Page 226: ......
Page 233: ...WFM 601 SERIAL COMPONENT MONITOR BNC INPUT BOARDS 1...
Page 237: ...ECL TO TTL CONVERTER LINE BUFFER RAM WFM 601 SERIAL COMPONENT MONITOR COPROCESSOR 3...
Page 245: ...Y FILTER Pb FILTER Pr FILTER WFM 601 SERIAL COMPONENT MONITOR Y Pb Pr RECONSTRUCTION FILTERS 7...
Page 247: ...WFM 601 SERIAL COMPONENT MONITOR TRANSCODERS PIX MONITOR OUTPUTS 8...
Page 249: ...0 0 0 0 WFM 601 SERIAL COMPONENT MONITOR LIGHTNING VECTOR BOWTIE SWITCHING 9...
Page 251: ...WFM 601 SERIAL COMPONENT MONITOR CONTROL DACULATOR 10...
Page 259: ...ROM MICROPROCESSOR NOVRAM RAM FLASH EPROM BUFFERS RESET ABORT WFM 601 SERIAL COMPONENT MONITOR...
Page 265: ......
Page 271: ...WFM 601 SERIAL COMPONENT MONITOR FRONT PANEL 20...
Page 282: ...WFM 601 FIG 1 EXPLODED VIEW A1 A2 A3 A4 A4A1 A5 A6 A7 A8...
Page 290: ...Glossary Glossary 8 WFM601 Serial Component Monitor...