promethean PRM-20, Service Manual

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electrical Adjustments
[Adjustment Condition]
●
Input signal
Video signal ........................ 1.0Vp-p/75
W
terminated, 16 steps gray scale
(Composite video signal)
Component Video signal ...... 1.0Vp-p/75
W
terminated, 8 color 100% color
bar or 16 step gray scale (Component video
signal)
Computer signal ................... 0.7Vp-p/75
W
terminated, 16 steps gray scale
pattern
●
Image control mode ......... “STANDARD” mode unless otherwise not-
ed.
Note:
* Please refer to “Service Adjustment Menu Operation” for entering the
service mode and adjusting the service data.
White 100%
Black 100%
circuit Adjustments
CAUTION: The each circuit has been made by the fine adjustment at factory. Do not attempt to adjust the following
adjustments except requiring the readjustments in servicing otherwise it may cause loss of performance
and product safety. Before adjustment, please turn on the projector more than ten minutes.
16 steps gray scale pattern
After replacing the Power Board readjust the Output
voltage adjustment as follows.
1. Connect a digital voltmeter to pins 1 (+) and (-) of
K6d
.
. Adjust the voltage by using VR611 as following.
AC Input Reading
0V 80V ±V
Caution:
Be sure to connect the lamp when taking this adjust-
ment.
* This adjustment is not required even if the power
board is replaced because this adjustment is carried
out before parts shipment.
Output Voltage adjustment
WArNING : uSe uV rAdIAtIoN eYe ANd SKIN
ProtectIoN durING SerVIcING.
cAutIoN:
to prevent suffer of uV radiation, those adjust-
ments must be completed within 25 minutes.
1. Enter the service mode.
. Connect a digital voltmeter to test point “
tPFANA
”
(+) and chassis ground (-). Select group no. “
250
”,
item no. “
0
” and change data value to adjust voltage
to be
5.0 ±0.1V
.
. Connect a digital voltmeter to test point “
tPFANB
”
(+) and chassis ground (-). Select group no. “
250
”,item
no. “
2
” and change data value to adjust voltage to be
6.2 ±0.1V
.
4. Connect a digital voltmeter to test point “
tPFANA
”
(+) and chassis ground (-). Select group no. “
250
”,item
no. “
1
” and change data value to adjust voltage to be
13.5 ±0.1V
.
5. Connect a digital voltmeter to test point “
tPFANB
”
(+) and chassis ground (-). Select group no. “
250
”,item
no. “
3
” and change data value to adjust voltage to be
13.5 ±0.1V
.
1.Fan Control adjustment
8 color 100% color bar
W Y C G
M R B
BLK
White 100% Black 100%