This problem seems relatively common. I have two units one with partial and one with a couple full columns out..
It would be nice if we could locate a replacement display to resolve the issue with a modern solution. The game machines have them... Greg On Tue, Sep 18, 2018 at 4:57 PM Jim Anderson <jim.ander...@kpu.ca> wrote: > > -----Original Message----- > > something > > making marginal contact on the LCD board. When it’s flexed > > slightly, > > the lines vanish, and the case presses on it just enough to make > > the > > problem crop up. > > [...] > > Is there a common failure mode for these panels or something else > > I > > should be looking at? > > See below for what I suspect is your actual problem, but I thought I'd > answer this first: there is a common failure mode which seems to affect > mostly M100 displays as far as I know, not the T102. It's pretty common > for vertical lines of pixels reaching halfway up from the bottom or halfway > down from the top to go blank, but they don't come back if you twist or > flex anything, and they don't seem to be related to bad contact but rather > to some bad component. I don't have more detail than that as I didn't get > into repair of my bad LCDs - I bought up a few trashy-looking M100s and > salvaged their display modules and a few other parts. > > > I don’t see how the panel itself is connected to the PCB. Perhaps > > there are pads on the top side and it’s simply the friction of the > > panel sitting on the board that does it? The more I poke around, > > the > > more I think it might be the PCB to panel connection. > > It certainly sounds like it, based on twisting causing the dead lines to > re-appear. The way that the panel connects to the PCB is through a pair of > what appear to be translucent rubber-like strips (IIRC - it has been a > while since I had an LCD apart so I might be wrong about them being > translucent). This is quite common with LCDs except the strips I am more > accustomed to seeing are made out of alternating black and white segments, > so it's easy to see that they have conductive and non-conductive sections > running through their thickness. The LCD is precisely aligned with the > PCB, which has conductive pads on it, and these strips conduct through to > the (nearly invisible) pads on the LCD panel glass. > > The LCD panel is clamped to the PCB by a metal frame which surrounds it > and which has small tabs which fit through notches in the PCB and are bent > over to secure it in place and apply continuous pressure. If you remove > the LCD assembly from the top case, you can put a little extra pressure on > different spots around the perimeter of the LCD by squeezing the top of the > metal frame down against the PCB with your thumb and forefinger. Firm > pressure, but not too much - remember it's glass. You should be able to > find the magic spot where the problem is happening. If you're lucky you > might be able to bend the tabs nearest to that spot to increase the > pressure and resolve the problem without taking it apart. > > If you're not lucky, there might be corrosion under the rubber-like strip, > and you'll need to disassemble it and clean it... it's possible, but > tedious and a bit risky. I'm not going into detail on that now because > this email is already getting a bit long. :) > > > > > > > > jim >
