Olivetti M15 LCD issues

[Retrom]

Hi all. I'm currently repairing a friend's Olivetti M15 laptop. The laptop has multiple faults that I need to sort out, but the one I'm currently dealing with at the moment is the LCD display, which has a bunch of horizontal lines missing from it. I tried removing the LCD from its circuit board and cleaning both the rubbery contacts on the LCD itself and the contacts on the board, but it had no effect on the issue with the display. In addition to the contacts on the top and bottom of the LCD, it also has a thin ribbon cable connecting to the side of it. Would it be likely that this cable is for the horizontal control of the display, and that's what's gone bad? Because if that's the case, I doubt there's a whole lot I can do to repair it (it looked secure and undamaged though). My other thought is that perhaps one of the surface-mount ICs on the back of the board has developed bad joints and needs to be reflowed. Although, pressing on random parts of the board and the LCD while the computer was on didn't have any effect on the display whatsoever, so I'm not sure if that's likely to be the fault either. Anyway, any input you guys could give me on this problem would be appreciated. Thanks!


What the display looks like when the computer is on:




ICs on the rear of the LCD panel's PCB:

 

[1ST1]

I think this is exactly what you did, contact of these rubbers between glass and board.

Do you have more experience in fixing M15? I have also one, which does not power up at all. Power supply is Ok. It has no big battery, the slot is empty.

 

[Retrom]

Well, so far I haven't had anymore luck in getting the display working. I've tried cleaning all the contacts, and resoldering the ribbon cable, but all to no avail. Other people I've talked to have told me that the display is probably bad. Not sure where I'm going to find a replacement now...

This laptop that I'm fixing also has power problems. It won't run on its own charger, as there's an issue with the laptop's internal DC-DC converter circuitry that I still need to fix. To get it to power on, I used a PC power supply, and applied 12v, 5v, and -12v to all the appropriate points on the motherboard's power connector. I suggest trying something similar on your laptop, and seeing if it'll start up.

This site has the pinout for the power connector on the board:
https://fjkraan.home.xs4all.nl/comp/m15/m15spec.html

 

[1ST1]

Hello, that's interesting. I already replaced all silicon based components and the capacitors on these two little boards which are between the power connector and the mainboard, without succsess.

Thanks fpr this link, very interesting, also for M10.

 

[Retrom]

When you replaced all the silicon based components, did you also replace the LA6358 op-amp, and the MB3775 switching regulator? Because for the moment, I currently suspect the MB3775 on this particular laptop might be faulty, but I haven't been able to test that theory yet.

 

[1ST1]

I don't remember the exact components, I replaced all, without a change of behaviour.

 

[silensilen]

When you replaced all the silicon based components, did you also replace the LA6358 op-amp, and the MB3775 switching regulator? Because for the moment, I currently suspect the MB3775 on this particular laptop might be faulty, but I haven't been able to test that theory yet.

Hi all. I'm currently repairing a friend's Olivetti M15 laptop. The laptop has multiple faults that I need to sort out, but the one I'm currently dealing with at the moment is the LCD display, which has a bunch of horizontal lines missing from it. I tried removing the LCD from its circuit board and cleaning both the rubbery contacts on the LCD itself and the contacts on the board, but it had no effect on the issue with the display. In addition to the contacts on the top and bottom of the LCD, it also has a thin ribbon cable connecting to the side of it. Would it be likely that this cable is for the horizontal control of the display, and that's what's gone bad? Because if that's the case, I doubt there's a whole lot I can do to repair it (it looked secure and undamaged though). My other thought is that perhaps one of the surface-mount ICs on the back of the board has developed bad joints and needs to be reflowed. Although, pressing on random parts of the board and the LCD while the computer was on didn't have any effect on the display whatsoever, so I'm not sure if that's likely to be the fault either. Anyway, any input you guys could give me on this problem would be appreciated. Thanks!


What the display looks like when the computer is on:

View attachment 1062612


ICs on the rear of the LCD panel's PCB:

View attachment 1062611

hi. I saw your old post about olivetti m15 repair. Can you explain to me how to disassemble the top cover with the screen? and won't the "sandwich" of the screen, conductive rubbers and the board fall apart?