PowerBook 160 - common problems to look for?

[ben68]

I have a PowerBook 160 that did work a few years ago, but when I plug it in and press power, it does nothing at all.

3 years ago, it worked flawlessly.

1 year ago, I could hear it power up, but the screen stayed dark.

Now it doesn't do anything.

I've checked the power supply, and it provides a solid 7.8V

Is there something that commonly fails on these that I can check?

Thanks!

 

[PB145B]

Take the main battery out, it usually gets shorted and prevents the laptop from starting. The screen staying dark is probably bad capacitors in the LCD and the inverter.

 

[ben68]

Thanks - I was able to start it up without the battery!

However, after a minute or two of smeary display, it went a white/blank color. Is that capacitors? Is that a easy or hard to fix? Which capacitors should I look at?

OK I found a video!

I hope it's easy.

 

[PB145B]

Great! Yes that is capacitor related. Here is a great tutorial on it.

https://m.youtube.com/watch?v=XP-fWaDbv5s

There are also a couple on the inverter board, which is directly under the brightness/contrast controls inside of the laptop. Those will most likely need replacing too.

 

[ben68]

Thanks - I have ordered the capacitors. I hope I can manage to do it. I'm a novice at soldering.

Question - if you know - those tiny ceramic capacitors - I don't see anywhere that they have a positive and negative - are they not polar?

 

[PB145B]

No ceramic caps are non polarized. Good luck getting it recapped! Post pics if you get it working!

 

[ben68]

Will do. I can see that one of the smaller caps is leaking, but the bigger caps -

100 uF 10V Electrolytic (EEA-GA1A101) x1
22 uF 35V Electrolytic (EEA-GA1V220) x1

Look like they aren't. 

Thinking out loud - the Youtuber listed the capaciter replacement for these two larger capacitors, and he suggested the electrolytics. I wonder if it's not better to go with ceramic for those too. I'm afraid to veer off the path too far though, since my electrical knowledge is limited.

 

[PB145B]

Yeah I bet once you pull the cap off there will be some leakage under it. I'm not sure if ceramic would work for that or not. Tantalum would definitely work though.

 

[Juror22]

Tantalums and ceramics work great for these.  (they help with size considerations as well) - be sure to make sure that you clean up the cap goo, whether or not you can see it.  Also make sure that you replace, or at least remove the PRAM battery that is on the interconnect board, those are starting to degrade after this length of time as well.

 

[PB145B]

The PowerBook PRAM batteries are starting to leak? Didn't know that! Time to open my PowerBooks and remove them! I think I should probably remove the yellow lithium batteries in my two IBM PS/2 model 30's as well, I could see those exploding eventually. Even though they are both still good!

 

[ben68]

I think I read somewhere that the voltage doesn't matter, so long as it exceeds the voltage of the original - is that right?

For example:

For a 100uF 10V, I could also use a 100uF 50V ?? but not a 100uF 5V

 

[IlikeTech]

Yes, you can always go up in cap voltage rating.

 

[ben68]

Is there any benefit in using higher voltage rated capacitors? I read a thread about de-rating. If they derate, then shouldn't you get the highest voltage capacitor you can find?

 

[IlikeTech]

Not unless they skimped on the rating originally. I would go up a little, but not like by 50 volts.

IlikeTech

 

[Rajel]

Yeah, try to find close in voltage rating if you can.
Replace *all* the electrolytic caps you can - if they haven't failed or started leaking yet, they will soon. Even if they don't look like it, it may be stealthily corroding what lies beneath.
Ceramics are ok for the screen, but tantalum caps often impart a higher resistance that may be unwanted.

 

[ben68]

If I replace the current electrolytics with like electrolytics, won't I have to replace them again in 20yrs? 

 

[Rajel]

Maybe, if you use crappy caps you may have to replace them sooner.
In a lot of situations, ceramic caps can be used to replace electrolytics.
There are some where you don't want to swap to ceramics though, like audio, video, and possibly power filtering circuits due to specific properties of each type of capacitor.
I used ceramic in my LCD recap, but it's possible electrolytics may have performed better with the LCD signals, and that could have factored into the design and use of electrolytics on the screen in the first place.

 

[Rajel]

Personally I'm happy with the result of using ceramics in my screen, and it's nice to know I'll likely never have to take that out and do it again.

 

[PB145B]

Yeah I always prefer using caps that won't leak ever again.