2.1.26 Vertical focus circuit
This monitor use double focus CRT, so it needs vertical and horizontal parabola focus signal to
input CRT G3 and G5 grid.
The vertical parabola signal is gotten from IC304 pin32 , and amplitued by IC308 and Q404 to obtain
about 200Vpp at the collector of Q404 , via T401 mixed with horizontal signal input FBT focus pack.
2.1.27 Horizontal focus circuit
The horizontal parabola signal is taken from Cs capacitor and amplified by T401 to acquire about
390Vpp amplitude at pin3 of T401 to combine with vertical parabola signal and input FBT focus pack.
2.2 Microcontroller Cricuit Operation
This model, 7299sl, will support powerful OSD function to help end user fine adjustment. The
Microcontroller circuit of the 7299sl can determine what mode it is by detecting the frequency of
horizontal and vertical synchronous and the polarity of horizontal synchronous, and provide DC voltages
to control the picture and save the adjusted value into the EEPROM by using the OSD, "On Screen
Display control", that means the user can get any information of the picture display or adjust it and save
the status values into the EEPROM by choosing and pressing the proper key according to the indication
of the OSD. In addition, user can press i-key to do auto-calibration.
2.2.2 Block diagram
The major parts of 7299sl Microcontroller circuit are MCU, EEPROM, OSD IC, and Auto Calibration
Module. The circuit block diagram is shown as below.
FIGURE.17 Dynamic Focus Circuit
No Copy/Reproduction Allowed
7299sl Service Guided