PowerBook 165 Grid Effect on LCD

[KGLlewellyn]

Hello!

First time poster here, but long time watcher. I've recently been restoring this PowerBook 165 that was sold as parts. I've re-capped the LCD and fixed the Connor Hard Disk using the epoxy resin trick. However, upon putting it back together after repairing the HDD I've been getting this odd grid-effect on the upper half of the screen. It appears that every other vertical line of pixels is displaying white. I've verified all my caps are still securely soldered onto the PCB, and the LCD was at one point working without issue before working on the hard disk. I've also checked the main display ribbon as well to ensure that there are no problems there.

Anyone have any ideas why this is happening?

Thanks!

 

[KGLlewellyn]

Looks like this issue occurred in this thread: https://68kmla.org/forums/index.php?/topic/56389-powerbook-140-lines-on-bottom-half-of-screen-and-clicking-sounds/

I'm going to double check to see if there isn't any solder shorting one of the traces near the LCD capacitors.

Will report back if it is resolved.

 

[Johnnya101]

Yup, that happened to be a speck of solder shorting out a trace. It appears to be in the top section, so check around the top section of the PCB for that. Should be close to where the pads are.

 

[KGLlewellyn]

Been working on this for about 3 hours and I haven't been able to track down what is causing the problem.

I'll attach some pictures to see if any of you can spot what's wrong. I know the caps I'm using aren't surface mount, but sadly it's all I was able to get on short notice. I'll swap em to something more fitting when I can get some. This was at one point working with no issues, but after I took the laptop apart to work on the Connor HDD, the screen started having this problem.

I've ran the multimeter across all the caps, and they are getting voltages varying between 2v-20v across them, so they should be working.

RE the pictuere; the issue is within the top half of the screen. In the picture with the whole screen pictures, the top half is closest to the camera - (it's the only half that has three capacitors on top of it)

I'm envisioning issues with the JP1 connection or the traces that supply it.

I've tried removing and re-adding Capacitors C2, C3, and C17 (on the top half) and C6, C7 and C8 (upper side board) to see if there was any difference and there was not.

Any advice would be great, thanks!

 

[bibilit]

I will have a look at the surrounding ICs (74H540) also the NR1 looks contaminated

 

[Johnnya101]

Looks like you used a bunch of solder on those caps. You sure the blobs of solder aren't touching other traces or ics? I can't really tell from the photos.

 

[techknight]

Umm, you broke the glass on the LCD! that thing is done bro.

Look in the corner. 

You have to be super careful when redoing LCD displays, gotta pay attention to detail and not manhandle it. Scrap it, get another LCD and try again.