Powerbook 520 and 520c Woes

[KeithTilton]

First of all, can I just say that the eBay prices for the M1893 power bricks are ridiculous?

I got a Powerbook 520c for free off Reddit in June and have been looking for a brick for a while to test it. I found a 520 with a power brick on eBay for $70 in a "non-working" state the other day and decided to take the plunge.

(Please excuse the mess behind the photos, I've been cleaning)

So the 520 arrived and turns on just fine. Unfortunately, it appears that the polarizer turned bad.



So this brings me to my first question. I'm able to remove the polarizer, clean all the adhesive off, and then stick a new polarizer on, restoring the screen, right? Just like this:

The laptop itself isn't in bad shape. If I can fix the polarizer issue, I would do the screen hinge fix that's posted on Thingiverse. I'd have a pretty decent looking laptop... of course, missing the port cover as usual.

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Since I tested that the power brick wasn't going to blow up my 520c, I decided to test that. The lady I got it from said the screen has a line which I can definitely deal with, however, I don't think I've ever seen a screen this yellow?


This is the line she must've been talking about. In all honesty, it's not that bad.



In the pictures it looks way less yellow than it does from my eyes. This can't be normal, right? Compared to any of my active matrix screens this is crazy yellow. I'm assuming this is the dual scan, but I may be wrong. I know that she mixed two Powerbook 520c's together and this is the worse of the two so I can't trust the model number on the bottom of the laptop.

Either way, I still want to do the hinge fix on both of these. I am just astounded at how bad both of these screens look. I'm just hoping that there's a chance I can save the 520's.

 

[Garrett B]

I agree that the pricing on the power bricks is crazy. The fact that you can buy a laptop and charger for what people are asking for a single charger is wild.

I have two 520 model laptops, and both of the LCDs are what I would consider to be poor. Contrast issues like crazy. I am thinking it's a similar issue to what the 1xx PowerBook experience when the capacitors leak and go bad, but I have not disassembled yet to find out. I'd think that would be a good place to start. Maybe someone has recapped one of these displays and can say for sure. Regardless, they look like clean machines!

 

[Byrd]

The yellow tinge to the screen would be due to a worn CCFL backlight - think of the yellowing that occurs in old fluorescent tube lighting in a house. Doesn't look dire though, with some "warming up" it might improve and you could also look into replacing the CCFL tube with LEDs.

 

[KeithTilton]

I agree that the pricing on the power bricks is crazy. The fact that you can buy a laptop and charger for what people are asking for a single charger is wild.

I have two 520 model laptops, and both of the LCDs are what I would consider to be poor. Contrast issues like crazy. I am thinking it's a similar issue to what the 1xx PowerBook experience when the capacitors leak and go bad, but I have not disassembled yet to find out. I'd think that would be a good place to start. Maybe someone has recapped one of these displays and can say for sure. Regardless, they look like clean machines!

So far no contrast issues, just the polarizer and the yellowing! I'm sure they'll need recapping eventually but I don't see any cap goo yet.

The yellow tinge to the screen would be due to a worn CCFL backlight - think of the yellowing that occurs in old fluorescent tube lighting in a house. Doesn't look dire though, with some "warming up" it might improve and you could also look into replacing the CCFL tube with LEDs.

I'll definitely run it for a bit and see if it lightens up. I was thinking that might be an issue, but figured I'd ask and see. I'm not super concerned, it was just far more yellow than I was anticipating. I will definitely look into replacing the CCFL tube if I decide this is too terrible.

 

[Franklinstein]

I agree that the pricing on the power bricks is crazy. The fact that you can buy a laptop and charger for what people are asking for a single charger is wild.

I have two 520 model laptops, and both of the LCDs are what I would consider to be poor. Contrast issues like crazy. I am thinking it's a similar issue to what the 1xx PowerBook experience when the capacitors leak and go bad, but I have not disassembled yet to find out. I'd think that would be a good place to start. Maybe someone has recapped one of these displays and can say for sure. Regardless, they look like clean machines!

Yeah I buy those power bricks as often as I can when I see them for reasonable prices. Sadly a good number of them have succumbed to bad caps and the case plastics are brittle so it's difficult to repair them without destroying the housing in the process. I usually end up piecing the chunks back together and wrapping the remains in duct tape and it holds up pretty well. Not really suitable for resale though. I wonder what they were thinking, making the 5x0 series (and then the notoriously crap 190/5300 mini-plug) with that goofy one-off power brick? They had already developed the Duo with the same now-ubiquitous barrel plugs; why didn't they use that in the first place? Would've saved a lot of trouble.

Sadly we're seeing lots of previously unknown failure modes with LCDs, from basic electrical faults (caps, etc) to chemical failures (especially polarizers but also some conductive rubber connectors and ribbon cable bonding material). Hopefully we can work out how to correct some of that but I don't hold out much hope for permanent solutions for problems such as tunnel vision.

 

[KeithTilton]

Well slightly good news, the 520c ended up whitening up a little bit after I left it on for a couple hours. Unfortunately it seems like the top of the screen is more yellowed than the bottom, but it really does look vastly better.

Yeah I buy those power bricks as often as I can when I see them for reasonable prices. Sadly a good number of them have succumbed to bad caps and the case plastics are brittle so it's difficult to repair them without destroying the housing in the process. I usually end up piecing the chunks back together and wrapping the remains in duct tape and it holds up pretty well. Not really suitable for resale though.

Ah great, I have to worry about recapping this power brick? I'll do that sooner rather than later. I'll have to add that as another reason I'm starting to have a distaste for the 520/520c's... even though I really think they're cute little laptops. They seem rather problematic.

 

[Franklinstein]

Yeah they're tightly-packed power bricks, much more involved than the 1x0-series types. There are a couple big caps and then a ton of smaller ones on a couple different boards. I'm not fond of repairing them, but they're not too much worse than their contemporaries. Case plastics, too: people love to rag on Macs for their fragile plastics, but PCs are not immune: I have a PII-based Dell, some DEC HiNotes, and a Micron or two with damaged cases including but certainly not limited to broken hinge mounts.

 

[3lectr1cPPC]

Let me guess: Latitude CP series? I have a CPi and both hinges are cracking. It’s definitely more than just macs.
@KeithTilton
You’re yellowed screen sounds like a worn out CCFL backlight to me.

 

[KeithTilton]

From what I've experienced, the Macs are just as bad as their contemporaries. My Toshiba Satellite from around the 520c's time period is falling apart as well. The whole early to mid 90's are a rough time for collecting between terrible caps and brittle plastics.

 

[Byrd]

From what I've experienced, the Macs are just as bad as their contemporaries.

The PowerBook 500 series introduced a lot of firsts so was a particularly big step up from earlier models and the added complexity made for quite an impressive, albeit fragile, machine. Keep an eye out for an active TFT display; you won't bother with the passive display after that.

 

[KeithTilton]

The PowerBook 500 series introduced a lot of firsts so was a particularly big step up from earlier models and the added complexity made for quite an impressive, albeit fragile, machine. Keep an eye out for an active TFT display; you won't bother with the passive display after that.

Oh definitely. I want one with an active matrix display... but I got my 520c for free with a 7600/132, a Beige G3, iMac G3, and Performa 6116CD. So no complaints on the price there.

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I ordered new polarizer film off eBay from China so here's to hoping I can fix the 520's screen.