My Toshiba Tecra 710CDT had a similar issue. A high pitched whine and an occasional but rare interference pattern across the screen.

The CFL inverter board is slightly different (model name UA0392P03).

These two electrolyte capacitors needed replacement.

They fully leaked out their electrolyte, was already corroding the second side of the circuit.

Luckily the circuit was still fine. Soledered out the old capacitors, used rubbing alcohol to remove the remaining electrolyte, and soldered in two new ones. Worked like a charm.

xnplater wrote on 2025-03-29, 16:38:

My Toshiba Tecra 710CDT had a similar issue. A high pitched whine and an occasional but rare interference pattern across the scr […]
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My Toshiba Tecra 710CDT had a similar issue. A high pitched whine and an occasional but rare interference pattern across the screen.

The CFL inverter board is slightly different (model name UA0392P03).

The attachment IMG20250328184155.jpg is no longer available

These two electrolyte capacitors needed replacement.

The attachment IMG_20250328_184619.jpg is no longer available

They fully leaked out their electrolyte, was already corroding the second side of the circuit.

The attachment IMG_20250328_192458.jpg is no longer available

Luckily the circuit was still fine. Soledered out the old capacitors, used rubbing alcohol to remove the remaining electrolyte, and soldered in two new ones. Worked like a charm.

The attachment IMG20250329120426.jpg is no longer available

Cool 😀 Good fix

The purple cap looks like it might be a solid polymer capacitor and I don't think those usually leak, but that 35v 10uF cap is the same one that always fails on the UA0392P01 inverter board.
Since capacitors don't cost much and opening up the display is a hassle, replacing both caps is a good idea to do regardless.

Could be!, the purple one still read ~12 uF on my multimeter! The black one was not showing anything, even when setting the multimeter to nF scale.

But as you said, as I have already taken them out and I had fresh capacitors at hand, I just replaced both.