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blabsxar
May 16th, 2017, 04:34 AM
Hi all!

I'm getting an beautiful and old NEC 286F. It seems it kind of works but the LCD backlight is almost dying. The current owner recorded a video of it being turned on and off:


https://www.youtube.com/watch?v=EhBCUOGGmWY

After talking to #vc guys on IRC and looking at some topics here at the forums, it seems that the first recommendations would be to change capacitors, right? I'm not a electronics guy (but I know some!) and I'm a vintage computer newbie so I'd like if there is any more informations like:

1. Changing the capacitors would be the right thing to do at first?
2. Does exist any electronic schematics?
3. If it doesn't work at all, is there any chance to connect it to an external monitor?

Thanks!

Bassoonbloke
May 18th, 2017, 02:14 AM
Hi,

The backlight on laptops is actually, usually a couple of very thin discharge lamps and these are driven by an inverter (takes a low voltage (12v dc) and steps it up to a much higher voltage (approx. 1kv)). If the inverter is dying, which does happen, you may be able to repair it (depending on your electronics, soldering skills) or get a replacement that will work.
I have not come across the tubes themselves going bad, but am happy to be put right on this.
The inverter is usually in with the display its self as part of the unit, but can be got at to see what is going on (beware, you can still get a bit of a Zapp from this even though it is very low current).
Give it a go.

Alan.

KenEG
May 18th, 2017, 03:08 AM
Hi,

The backlight on laptops is actually, usually a couple of very thin discharge lamps and these are driven by an inverter (takes a low voltage (12v dc) and steps it up to a much higher voltage (approx. 1kv)). If the inverter is dying, which does happen, you may be able to repair it (depending on your electronics, soldering skills) or get a replacement that will work.
I have not come across the tubes themselves going bad, but am happy to be put right on this.
The inverter is usually in with the display its self as part of the unit, but can be got at to see what is going on (beware, you can still get a bit of a Zapp from this even though it is very low current).
Give it a go.

Alan.

I used to repair laptop computers as a hobby. Dim screens are almost always the inverter.