Ds80061 Mainboard Failure Analysis; First Meet Vga Display; First Meet Vout Monitor - HIKVISION DS7208HVI-ST Product/Maintenance Manual

6. DS80061 Mainboard Failure Analysis

VGA and VOUT and output image, but not at the same time output system
menu, the system default first detection VGA output, then detection VOUT
output

6.1. First Meet VGA Display

Boot to meet VGA monitor (or also meet VGA display and VOUT monitor),
BAV99 (Q6) PIN 3 low level effective, display output VGA signal and system
menu, monitor only VOUT signal

6.2. First Meet VOUT Monitor

Boot first meet VOUT monitors, BAV99 (Q9) 3 feet is high level, the high level
signal feedback to the CPU, monitor output VOUT signal and system menu,
display show only the VGA signal
Note: ① BAV99 (Q9) 3 feet high level, only output signal VGA monitor, monitor
and output signal and system VOUT menu
② BAV99 (Q9) 3 feet low level, display and VGA output signal and system
menu, monitor only output VOUT signal
6.3 Fault Analysis
①. No VGA Output
Step 1: measure 1 K resistance (RL50/51), or replacement (1 K value too large,
LVC07A chip PIN 2 VS signal output, PIN4 HS signal output voltage
value will be lower, then cause no VGA output)
Step 2: measurement 33Ωresistance (RG30/31), or replacement
Step 3: using a multimeter to measure LVC07A PIN 1 input (VS signal) voltage
about 3.3V and PIN 3 input (HS signal) voltage 3V also, and then
measure PIN 2 output (VS signal) voltage about 5V, the PIN4 output
(HS signal) voltage about 4.3V, otherwise LVC07A ruled out