JHL90 Service Manual
Symbol Description
1 HV Connected to high voltage of LCD lamp
2 LV Connected to low voltage of LCD lamp
Note: Please mark “CAUTION HIGH VOLTAGE” around CN2
4.6 Safety Protection
4.6.1 Open lamp protection:
When inverter is on open lamp status, any component on inverter should be O.K
and inverter is no damaged, no fire and no arcing. If inverter can’t shunt down
during open lamp happen, inverter must pass below conditions:
• Human body test.
• Open lamp burning: Inverter burns for 24 hours at open lamp status. No parts
damage.
4.6.2 Human body safety test:
Short inverter output, transformer secondary output to GND by a 2KΩ resistor
which connects one end to GND and another one to those outputs. They should
meet output current limitation requirement as follow. Output current I is the
current that flows through 2KΩ resistor.
• Output current I ≤ 0.7mA, if frequency f ≤ 1KHz
• Output current I ≤ 0.7mA * f (kHz), if f ≥ 1KHz.
However, output current should be less than 70mA even frequency is more than
100KHz.
4.6.3 Abnormal test:
Any one component is short or open; inverter should be no fire, no arcing. And
result must meet output current limitation requirement.
4-16
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