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Lines and ghosting on vintage LCD panels

R

RetroHospital

Experienced Member
Joined
Oct 20, 2020
Messages
181
Location
Belgium
Hey everyone

I'd like your opinion on this problem that I see on a lot of my vintage LCD, especially the monochrome ones

IMG_6253.jpg

This is for example taken from a Compaq SLT , but I've got the same thing on a completely unrelated Toshiba T2000 or even a fully recapped powerbook 100

I wonder what is the cause, a few people talk about the inverter board but in the case of my screenshot the inverter board only has a single 100uF capacitor which I highly doubt would be a cause for this. I've also seen this problem on fully recapped screens

Does anyone have an opinion or advice on this ?
 
Probably failing interconnections inside the panel. On the other hand, the lines match up with parts that have high contrast change in the picture, so they might even be normal for this type of panel.
 
Exactly - the lines match high contrast areas, and I was a teenager when the compaq slt hit the market so I couldn't see one first hand :)

I'm starting to wonder of this is "stock" or not, I guess it's worse than when it was new but I just don't know :(
 
Most of my Apple Powerbooks with passive screens have such lines as well (except my PB190cs). But as you, I never owned these when they were new. LCD panels were crappy back then, however, so probably that's just how they are. I think this has to do with the charge needed to turn a pixel fully black. The charge will leak over the rest of the line (or column).
 
They were pretty crappy back then too, with ghosting of lines triggered by interface components like this. It wasn't quite this noticeable when new, but still visible. The difference is that then it was possible to adjust the brightness/contrast to minimize the visual impact, whereas by now, the range of adjustment available is typically not so good.

One of the potential issues relates to electrolytic capacitors in the display panel control circuit, which like these components elsewhere are typically degraded and even leaking by now. While I haven't done this with any of my old LCD panels, I have seen photos of before and after that indicates recapping LCD boards can help greatly to restore almost-new display quality.
 
Ghosting like that is perfectly normal on passive-matrix LCDs. They were like that even when they were brand new. The only "fix" is to replace it with an active-matrix LCD.
 
Looks normal to me. My AST Advantage SME-486 has the same lines when there' a lot light and dark change on the same pixel column. It's always had this since I got it in 2011.
 
That’s what I call “shadowing.” Perfectly normal for that type of display. All part of the retro charm of you ask me!

The Compaq SLT had an incredibly sharp and bright LCD for the era.
 
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