Some unusual components

[msuffidy]

There are 2 sets of components I think are rather odd on this inverter board I got out of an older LG Flattron monitor. I put red asterisks on the components. Isn't that a lot of transformer coils? And the other things look like metal blocks for what reason?

[msuffidy]

The backlight was sort of flickering darker and I thought maybe it was some cold solder joint, but I decided I was through with this monitor as it took a lot of dings in the past switching the caps. Some data pointed to maybe a connection issue with the backlight connectors on the inverter board. There were a lot of fluxy joints.

[T3sl4co1l]

What's the designator? HS? Guessing there are SMD transistors on the bottom and those are heatsinks.

The section is a CCFL driver, several evidently (big enough screen to need them, it seems).  The transformer is wound in multiple sections to reduce capacitance between its many (thousands?) of turns, allowing the generation of high voltage at high frequencies.  It operates in a resonant mode, most likely a traditional two-transistor ZVS (Baxandall) oscillator.

Tim

[amyk]

The multiple-section coils also help with isolation, since their output voltage is very high.

[shakalnokturn]

The transformer is wound in multiple sections to reduce capacitance between its many (thousands?) of turns, allowing the generation of high voltage at high frequencies.  It operates in a resonant mode, most likely a traditional two-transistor ZVS (Baxandall) oscillator.

Although it will have some effect on inter-winding parasitic  capacitance I'd expect that the separate sections on the HV secondary are to prevent wire insulation breakdown by keeping the voltage between layers low enough.

While Baxandall oscillators are sometimes seen on small single CCFL inverters, most of the time large screens are driven by dedicated oscillator / control IC's that allow for PWM dimming and monitoring CCFL condition.

[T3sl4co1l]

Indeed, which seems to be the case here (the nearby DIP IC).

Hm, also there's six transformers but only four heatsinks, seems likely they're driven in parallel on the primary side, and that would make the job easier for a management chip too.  Hm, I wonder if they're doing full bridge then, and varying frequency with PWM (phase shift PWM even?) or frequency.

Have also seen controllers (usually amounting to a simple buck converter or even plain fixed PWM into the supply inductor) used with oscillators.  Doubt that's the case here.

Tim