Compaq D-1H Section Safety Related Adjustment, b HV Hold-Down Check, Check Condition

P75

SECTION 3

SAFETY RELATED ADJUSTMENT

When replacing parts shown in the table below, the following operational checks must be performed as a safety precaution against X-ray emissions from the unit.

D - BOARD

Part Replaced ([)

RV501

Part Replaced (])

RV501, T501, R545, R546, R548, R550, R547, R549, R552, D517, IC605, IC901, C540, C542, C544, C541, C535, IC501, C558, R567, R564, C555, C553, C554, C561

Allow the unit to warm up for one minute prior to checking the following conditions:

b)HV Hold-Down Check

1)Using an external DC Power supply, apply the voltage shown below between cathode of D517

on "D" Board and GND, and confirm that the HV Hold-Down circuit works. (Raster disappears)

Apply DC Voltage: 31.4 + 0.01 VDC

Check Condition
•	Input voltage	: 120	+ 2 VAC
•	Input signal	: (fH = 64 kHz), White Cross Hatch
•	Controls	: CONT (max) & BRT (center)
•	B+ Voltage	: 185	+ 3.0 VDC

c)Beam Protector Check (Software logic)

1)Using an external DC power supply, apply the voltage 8.8 + 0.01 VDC between pin 11 of FBT (T501) and GND, and confirm that the voltage across C541 is 3.7 VDC or less.

a) HV Regulator Check

1)Input white cross hatch signal. (fH = 64 kHz)

2)Minimum CONT and BRT controls.

3)Cut off Screen VR (G2).

4)Input voltage: 120 + 2 VAC

5)Confirm that the voltage is within the voltage range shown below.

Standard voltage: 25.0KV + 0.5KV

6)When replacing components identified by ], make sure to recheck the High Voltage.

7)Verify the High Voltage as shown above (25.0KV + 0.5KV) is within specification. If not, set H. SIZE data at minimum (-127) and then adjust RV501 on "D" Board.

8)After adjusting the High Voltage within specification, put the RV cover on RV501 as shown below and apply sufficient amount of RTV around RV501.

Check Condition
•	Input voltage	: 120 + 2 VAC
•	Input signal	: (fH = 64 kHz), White Cross Hatch
•	Controls	: CONT (max) & BRT (center)

d)B+ MAX. Check

1)Input white cross hatch (fH = 64 kHz) signal.

2)CONT (max) & BRT (center)

3)Input voltage: 120 + 2 VAC

Note: Use NF power supply or make sure that distortion factor is 3% or less.

4)Confirm that the voltage is within the voltage range shown below.

Standard voltage: 185 + 3.0 VDC

R V 5 0 1