Adjustment; Adjustment Conditions And Precautions; Main Adjustments; Adjustment Method - Tatung VM5ERDA Service Manual

4-1 ADJUSTMENT CONDITIONS AND PRECAUTIONS

1. Approximately 30 minutes should be allowed for warm up before proceeding.
2. Adjustments should be undertaken only on those necessary elements since most of them have been carefully
preset at the factory.

4-2 MAIN ADJUSTMENTS

NO. FUNCTION
1. 15V ADJ
2. B + ADJ
3. R.B. DRIVE
4. R.G.B. CUT-OFF
5. ABL ADJ
6. UP KEY
7. DOWN KEY
8. FUNCTION KEY

4-3 ADJUSTMENT METHOD

1. 15V, B + & HV protection voltage adjustment:
A. Chroma-2000 Signal generator or PC equivalent, set mode 2( VGA 640 × 480) pattern 1.
B. Connect a DC voltage meter between TP 901 and ground, then adjust VR901 to be 15VDC.
C. Connect a DC voltage meter between TP 902 and ground, then adjust VR902 to be 88 VDC.
2. Factory preset timings adjustment:
A. When you turn on the monitor, the function LEDS will light up simultaneously for a while, then extinguish.
B. You can press the up/func two keys simultaneously, the most left four LEDS will light up for a while then
extinguish.
C. Then you can select one of the eight functions including Contrast, Brightness, H-SIZE, H-CENTER, V-
SIZE, V-CENTER, Pincushion and Trapezoid Simply press the function key and the LED will be light up
corresponding to the one selected, then press the up/down keys to get the factory presetting parameter value
to your satisfaction.
D. Then you will press the up/function two keys simultaneously again, the most right four LEDS will light up
for a while then extinguish, the factory preset timings adjustment is finished.
3. White balance and luminance adjustment:
A. Bias (low light) adjustment:
(a) Set mode 4 ( 800×600 Fh: 53.7KHz ) full white pattern.
(b) Adjust VR801, 802, 803, 804, 805, to make VR in the center position.
(c) Warm up more than 20 minute.
(d) Brightness set to max. Contrast set to min. full white pattern, then adjust FBT screen VR to make Y=
4.7±0.3cd/m².
(e) Brightness set to raster just cutoff, contrast set to 14cd/m², then adjust CRT board VR805 (B-Bias)
VR803 (R-Bias) to make Y= 14 ± 2cd/m², x= 283 ± 10, y= 298 ± 10
B. Gain (High light) adjustment:
(a) Set mode 4 ( 800×600 Fh: 53.7KHz ) full white pattern.
(b) Brightness set to raster just cutoff and set the cantrast to max.
(c) Adjust VR801, 802 to make color code x=283 ± 10, y=298 ± 10.
C. Recheck item A&B to make sure both of them in spec.

4. ADJUSTMENT

LOCATION
PCB - MAIN
PCB - MAIN
CRT - BOARD
CRT - BOARD
PCB - MAIN
PCB - MAIN
PCB - MAIN
PCB - MAIN
DESIGNATION
VR901
VR902
VR801,802
VR803,804,805
VR701
SW101
SW102
SW103