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I have a IBM 390X which had a 15.0" screen but it had gotten damaged. I bought a IBM 390X 14.1" screen at E-bay thinking to replace it. I have connected the 14.1" screen but I have not been able to get it to work. The screen's power LED glows so I know it is receiving power but apart from that, the screen remains black.

I would like to know if even though an LCD screen is meant for the same laptop, the screen size would actually make a difference?

Thanks for any advice.

morningtemplar

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Dani AI

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raised the right checklist items to start with. Size alone (15" vs 14.1") does not guarantee incompatibility, but a physically matching connector can still hide electrical or timing differences. The useful next steps are focused, low‑risk checks you can do before buying parts or opening the board.

  • Identify the panel part number on the sticker behind the bezel and compare it with the replacement. If they differ, download or request the panel datasheet and confirm the interface (LVDS vs TTL), pinout, and native timing/resolution.
  • With the laptop powered and the lid up, shine a bright flashlight at an angle onto the dark screen. A faint image means the panel is receiving video but the backlight (inverter/CCFL) is dead or not being driven. No image at all points toward signal/pinout mismatch or a bad panel.
  • Reseat and inspect the LCD cable and connector for bent pins, torn shielding, or corrosion. Intermittent contacts are a very common cause; a firm reseat often fixes symptoms without further work.
  • If the backlight appears dead, compare inverter part numbers and, if competent and cautious, check for the inverter high‑voltage output. High voltages are dangerous; get a technician if unsure.
  • Contrast/osd problems after a swap usually mean the panel’s control lines or in‑panel potentiometer differ. That is separate from a missing image and often requires a panel-specific control board or the original inverter/power board.

If the replacement panel is not the exact part or its datasheet shows different signalling/pinout, stop and get a confirmed compatible part. Mismatched wiring can permanently damage the panel or motherboard. For used parts bought online, always ask the seller for the exact part number and a working test report.

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I don't know much about LCD laptop screens. However, here are some questions to consider:
1. Is the laptop compatible with any other monitors?
2. Is the ebay monitor in working condition?
3. Is the ebay monitor compatible with your laptop?
4. Is the ebay monitor supported by your video card?
5. Is the native resolution of the ebay monitor compatible with your video card?
6. Is the ebay monitor correctly hooked up your laptop? (e.g. getting power, video signal)

Member Avatar for morningtemplar

The laptop works perfectly with a CRT monitor. As for the LCD screen from Ebay, it is meant for the same laptop model, IBM 390X and the screen is getting power.

I suspect the problem lies with the original screen being a 15" as opposed to the 14.1" which I just bought.

The data cable and power cable are identical.

morningtemplar

Member Avatar for morningtemplar

I finally got the laptop screen to work when I banged it out of frustration. So I guess if the plugs are compatible it will work although contrast control slider does not work.

morningtemplar

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