This is the most critical section for a "dead TV" scenario. The standby circuit is always active when the TV is plugged in. It typically uses a PWM controller IC (often a DIP-8 chip like the OB2273, LD7535, or NCP1207).
+Vin (36V max) ----[Fuse]----[Reverse Polarity Diode]----+----[C_in+]----[C_in+]----+----[L1]----+----[C_out+]----[C_out+]---- Vout+
| | |
| [Q1 Drain] |
| | |
+----[U1 Vin] | |
| | |
| [Q1 Source] |
| | |
+----[D1 Cathode]------[D1 Anode]---[GND]
|
+----[R_sense]----------------------[GND]
|
+----[RV1 wiper]----[U1 FB]
|
[GND]
The brain of the S36012 power supply circuit diagram is the TL494 IC. Its pins are configured as follows: s36012 power supply circuit diagram
Refer to the feedback network: Tap the output voltage divider before the pot to feed a panel meter. Do not load the FB pin with a low-impedance meter (use a buffer op-amp). This is the most critical section for a "dead TV" scenario
Below is a breakdown of the critical stages you will find in a schematic diagram of the S36012 board. The brain of the S36012 power supply circuit
Before diving into the schematic, let’s establish the functional blocks of the S36012: