Recently, a friend's Sony KV-XR29M31 TV suddenly stopped working.
A preliminary examination revealed that the power supply primary side MOSFETs (Q607, Q608) have gone short circuit, with a fusible 0.1 ohm resistor (R642) going open circuit (All had no visible damage).
Later examination also revealed that the horizontal output transistor (Q511) have gone short circuit (Again, no visible damage).
Replacing those components, along with C551 (with a polyester unit) and C528 fixed the problem.
But I am still wondering how the power supply primary side MOSFETs (or transistors) would short out when the horizontal output transistor shorts out?
I've encountered something just like it in an old set someone gave me to fix.
A preliminary examination revealed that the power supply primary side MOSFETs (Q607, Q608) have gone short circuit, with a fusible 0.1 ohm resistor (R642) going open circuit (All had no visible damage).
Later examination also revealed that the horizontal output transistor (Q511) have gone short circuit (Again, no visible damage).
Replacing those components, along with C551 (with a polyester unit) and C528 fixed the problem.
But I am still wondering how the power supply primary side MOSFETs (or transistors) would short out when the horizontal output transistor shorts out?
I've encountered something just like it in an old set someone gave me to fix.
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