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Home Forums Powerbook 140 with screen issues — #15 Powerbook 140 with screen issues — #15
Post #15 by pintodave
Source ForumPowerbook 140 with screen issues — #15
CategoryTroubleshooting
Post DateTue, 30 Sep 2014 - 19:54
Original URLhttps://68kmla.org/bb/threads/powerbook-140-with-screen-issues.269/
Post
And last but not least, some photos of the repair(s)

These are the temporary replacement caps until the new ones arrive:

IMAG2702_zps4a151089.jpg.3c1a31f0f9cf45618b97234c39dcfc5c.jpg


I replaced the cap on the far right of the image below with a new tantalum that I had lying around. I didn't have any other caps to do the rest of the screen, so this picture was taken for reference, both for me and for others. The tantalum cap is a 100uf 35V, the rest of the caps have their values still printed on them.

IMAG2699_BURST002_zps83dbbca9.jpg.e2f72211fd6fec1550f05d7d5874ee89.jpg


These are the rest of the caps to be replaced, towards the bottom left corner of the LCD screen assembly.

IMAG2700_BURST002_zps5d27c498.jpg.f49e2a998996758ca8b8794c0771ef22.jpg


This right side was the worst of the hinge posts. The innermost post actually broke apart during disassembly, but the brass insert stuck to the screw. With some patience and some JB weld, I was able to rebuild the posts and strengthen/reinforce the other posts on the display housing.

IMAG2703_BURST002_zps45c9793e.jpg.22c9134e606296833c778183c076abdf.jpg


IMAG2704_BURST002_zpsf9a08c31.jpg.33fab353e06a73ec8f850dd742791367.jpg


Even after replacing only that ONE capacitor with a tantalum, I was able to get a better image with dark backgrounds. This is with the default grey background.

IMAG2720_BURST002_zps31f269d7.jpg.5c0169456b4c2dafffe322e50939b790.jpg


The only difference I am seeing, aside from being brighter, is it now takes about five minutes for things to "warm up". The display starts out dark upon power on, but slowly gets brighter and the contrast has to be adjusted to compensate.

I am hoping the new caps will fix all of this!

mp.ls