Hi everyone,

I’ve been troubleshooting a dead TL-PA4020P (no LEDs, no signal). After several tests, I have identified the root cause of the failure.

The LNK623DG (PWM Controller) was initially blown. After replacing it and the main electrolytic filter capacitor (which had a high ESR), the new IC was still overheating rapidly (reaching 77°C/170°F in seconds).

I desoldered the switching transformer (Part No: 3510500114 PL 1452) to isolate the circuit. Here is the technical verdict:

Primary Winding: Measuring 0.0 Ohms (dead short) between the two primary pins.

Secondary/Auxiliary: Pins are clean and readings are within expected ranges.

Diagnosis: Internal short-circuit in the primary windings due to insulation breakdown (likely caused by 24/7 heat exposure over the years).

Since this is a custom transformer, I’m looking for a replacement or a compatible part number. Has anyone successfully sourced this transformer or found a compatible flyback alternative for this specific board?

Any help or lead on where to find the part would be greatly appreciated!