Macintosh Portable M5120 Display issue

[Borgmac]

After successfully recapping and replacing the Hybrid (thanks again @Androda ), I needed to correct one faulty matrix line of the display.

I replaced the flat ribbon connector as it was torn at different places.
Unfortunately, same issue.
Checking the back of the display more carefully, I realized that there was a kind of corrosion under the protective adhesive.
I had this type of corrosion once in a LCII PSU, probably due to a bad board cleaning at manufacturing.
Sorry for the bad quality, my camera was out focus...

To my surprise, after replacing the protective adhesive, pads were perfect!

Back to square one.
Checking the whole board, I realized that other areas have the same aspects.

I plan to remove the protective adhesive from the additional places, but is it normal to have these solder connecting pads?
I have that at 4 different places on the board.
Thanks for your advices.

 

[Sideburn]

These LCDs are a nightmare. I’ve tried to repair two of them end they just got worse and worse. I had one that was perfect then a lone speared one day. Then Another. Then 5 more. Ahhhhg

I replaced drivers etc. I think it’s the pads on the glass itself and not the board or the zebra strips.

 

[Sideburn]

After successfully recapping and replacing the Hybrid (thanks again @Androda ), I needed to correct one faulty matrix line of the display.
View attachment 13548
I replaced the flat ribbon connector as it was torn at different places.
Unfortunately, same issue.
Checking the back of the display more carefully, I realized that there was a kind of corrosion under the protective adhesive.
I had this type of corrosion once in a LCII PSU, probably due to a bad board cleaning at manufacturing.
Sorry for the bad quality, my camera was out focus...
View attachment 13549View attachment 13550
To my surprise, after replacing the protective adhesive, pads were perfect!
View attachment 13551
Back to square one.
Checking the whole board, I realized that other areas have the same aspects.
View attachment 13552
I plan to remove the protective adhesive from the additional places, but is it normal to have these solder connecting pads?
I have that at 4 different places on the board.
Thanks for your advices.

Yea the solder bridges like that are normal.

 

[SuperSVGA]

Those solder bridges are actually a form of bodge. There's line numbers next to the pads on the edges, and there are corresponding line numbers on pads connected to the driver chips on the opposite end of the board. If for some reason there's a bad connection, this allows you to connect the same line using the elastomeric/zebra connector that's on the opposite side of the LCD. It is limited to one bodge per side of the driver chip however.

 

[Borgmac]

OK, I am not going to try repairing that display anymore.
Thanks @Sideburn , I have seen your experience made last June and understood that trying to repair these zebra strips is actually generating more blank line than removing them.
A nice option is the VideoMacPack card, copied and improved some years ago:

GitHub - apmcpherson/VideoMacPacHack: Clone of the Video Mac Pac PDS video card for the Macintosh Portable

Clone of the Video Mac Pac PDS video card for the Macintosh Portable - apmcpherson/VideoMacPacHack

github.com

I do not have the knowledge to build one, but may be some others could be a few of them, I an sure that several Macintosh Portable owners are ready to buy some. @Androda , may be a nice addition to your shop?
While waiting for it, A single line is actually acceptable.

 

[Sideburn]

I finally found a decent display now. It has one dead pixel that I’m trying to not let mother me

…and I have two that have lines all over the place. I’m just crossing my fingers my third one doesn’t start acting up! lol I’m going to be parting out and selling two portables. I’ve repaired and re capped both logic boards.

that card looks cool but I’m all about restoring these machines back to pristine original working condition.

meet need a repro active matrix lcd panel!

 

[wottle]

I might be in the market for a Portable logic board. Mine was originally working fine, but now refuses to boot past a partial boot chime. Haven't had a chance to dig in to figure out what might be going on, but I had a decent amount of damage around the hybrid board and I repaired a few traces that were damaged. Maybe those repairs failed, or there are others I missed.

 

[Sideburn]

Are there black stains on the pins on the hybrid board? Corrosion from cap leakage destroys that board. Out of about 4 boards I’ve repaired so far only one has a working hybrid. I’ve replaced all the others with ones from SuperSVGA on here. Androda also makes them.

 

[Androda]

OK, I am not going to try repairing that display anymore.
Thanks @Sideburn , I have seen your experience made last June and understood that trying to repair these zebra strips is actually generating more blank line than removing them.
A nice option is the VideoMacPack card, copied and improved some years ago:

GitHub - apmcpherson/VideoMacPacHack: Clone of the Video Mac Pac PDS video card for the Macintosh Portable

Clone of the Video Mac Pac PDS video card for the Macintosh Portable - apmcpherson/VideoMacPacHack

github.com

I do not have the knowledge to build one, but may be some others could be a few of them, I an sure that several Macintosh Portable owners are ready to buy some. @Androda , may be a nice addition to your shop?
While waiting for it, A single line is actually acceptable.

I've been thinking about something that could work with the video out port on the Portable. I keep trying to move on to things other than the Portable but it keeps pulling me back (yet another Portable project is underway now at the schematic stage).

The VideoMacPack is particularly weird, the FPGA is programmed by the Mac when the control panel loads. And that means it would be near-impossible to port to a new FPGA because you can't go back from bitstream to logic without a large time investment. it also means you wouldn't be able to see the near-inevitable sad mac when something else goes wrong.

 

[ClassicHasClass]

Boy, it would be something if you could get a dongle working with that. You can take my money now.

 

[wottle]

Are there black stains on the pins on the hybrid board? Corrosion from cap leakage destroys that board. Out of about 4 boards I’ve repaired so far only one has a working hybrid. I’ve replaced all the others with ones from SuperSVGA on here. Androda also makes them.

I replaced it with one of @Androda 's boards. It was working. I put it up for a bit and now it only boots a fraction of the boot chime. Battery voltage is fine...

 

[Sideburn]

Ahh, hmm. you could try en external power supply if you have one set to 7.5v / 2A and connect positive to pins 1&3 of J13 and GND to pin 2 or 4 and see if theres any difference. Does the display come on? sounds like its starving for voltage.