LG HW300Y Service Manual page 28

3. Trouble shooting - No video (Analog TV video)
Check RF Cable & Signal
Check Tuner 3.3V Power
(Main) L513
ok
Check Tuner 1.8V Power
(Main) L515
ok
Check IF_P/N Signal
(Main) R526, R529
ok
Check IF_P/N Signal
(Main) R530, R531
ok
Check C891 (Main)
ok
Replace BCM (10) or Main Board.
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Only for training and service purposes
No
Check (Main) IC502, Replace IC502
No
Check IC503, Replace IC503
No
Bad Tuner. Replace Tuner.
No
Check R921, R923
No
Replace C891
LGE Internal Use Only