GDM-200PS/200PST/200PST9
SECTION 3
SAFETY RELATED ADJUSTMENT
When replacing or repairing the shown below table, the
? Beam Current Protector Circuite Check
following operational checks must be performed as a
(1) Hardware logic circuit
safety precaution against X-rays emissions from the unit.
? Turn the POWER SW on, and check that the RASTER
fades in.
Part Replaced ([)
? Connect a variable resistor (20 kW or more) and an
HV ADJRV901
ammeter in series between FBT pin !] and � 15 V line
(� side of C637). Decrease gradually the resistance of
Part Replaced (])the variable resistor from maximum to minimum, and
confirm that the Beam Current Protector Circuite
HV RegulatorD board IC901, R903, R922,
CircuitT901works (TV Rester disappears). The current must be
Y Mounted D boardwithin the range shown below.
HV HOLDD board D913, D916, C923,Standard current: Less than 1.09 mA
DOWN CircuitR920, R927, T901
Y Mounted D board(2) Software logic circuit
Beam Current D board IC901, D902, D918, ? Turn the POWER SW on, and check that the RASTER
Protector CircuitD919, R923, R928,fades in.
R932, R933, R934,? Short between + of C639 and GND.
R942, R944, R945,
? Connect a variable resistor (20 kW or more) and an
R947, R948, R951,
ammeter in series between FBT pin !] and � 15 V line
T901
(� side of C637). Decrease gradually the resistance of
Y Mounted D board
the variable resistor form maximum to minimum, and
* Confirm one minute later turning on the power.
confirm that the Beam Current Protector Circuite
works (TV Raster disappears). The current must be
? HV Protector Circuit Check
within the range shown below.
(1) Confirm that the voltage between cathode of D913
Standard current: Less than 1.14 mA
and GND is more than 17.5 V DC.
(2) Using external DC Power Supply, apply the voltage
shown below between cathode of D913 and GND,
and confirm that the HV HOLD DOWN circuite
works. (TV Rester disappears)
Standard voltage: Less than 23.40 V DC
3-1 |
ACEC
