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PowerBook Duo 230 repair and preventive maintenance


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A while ago I picked up a cheap Duo 230 with a cracked screen that was otherwise working, been on the lookout for parts machine and recently found one that appeared to have a good screen.

 

Combining them into one did result in a working machine (yay!), but both screen lids had broken hinge area screw stand-offs that needed repair, and before buttoning everything up I thought it would be a good idea to replace the logic board and LCD capacitors too.

 

Hinge Repair:

 

There is a lot of info/discussion out there on this problem common to a lot of PowerBooks, the bottom line is the plastic case pieces that secure brass stand-offs crack and break off over time and use which not only leads to non-secured components but also further case damage due to new stress points.

 

The fixes/repairs all involve finding a way to reestablish a case secured mounting point for the screws in question. Most seem to focus on resecuring the original brass stand-offs but I have seen drill holes and use case external screw nuts.

 

I had thought about making an ABS slurry with broken bits of other PowerBook plastic and acetone but after some unsuccessful tests I decided use JB Weld PlasticWeld epoxy. I was hopeful as it specifically mentions ABS plastic compatibility. 

 

I cut away the broken/remaining plastic pieces of the brass stand-off support, made sure the brass stand-offs were seated in the remain original depression and applied the epoxy with a wooden chopstick. The thickish epoxy sets relatively quickly but you have plenty of time to work with it. The fact that it spreads seems like a plus to me, more surface area to to bond with. 

 

I think It turned out great, although I guess only time will really tell.

 

5AC17A29-34D8-48B8-B616-553268477A6D.jpeg.dfc35e7fb5bdb712a08458f9dfb910f0.jpeg

 

 

89CB6557-AB1B-4BEC-8BA6-464AA4B97223.jpeg.1e9f87630515373fc3dc1f9c169c43da.jpegA2A81DEC-1DED-4F87-9C9D-04C6D16FA9CE.jpeg.f972d3352a5fd717e0c92772a1c5865c.jpeg

 

 

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On to the logic board capacitors!

 

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PowerBook Duo 230 (820-0426-D) logic board capacitors:

   2 x 100uf - 25v - D:8mm H:10mm (C2, C11)

   3 x 100uf - 35v - D:10mm H:10mm (C3, C5, C9)

   1 x 330uf - 16v - D:10mm H:10mm (C14)

   1 x 33uf - 25v - D:6mm H:6mm (C36)

 

I didn’t see any leakage so I did hesitate a bit but decided to proceed since I had two working boards and they are bound to leak eventually.

 

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Removing the capacitors turned out to be a bit of a chore, mainly since I didn’t feel comfortable using the twist off method with the larger, non-corroded, cans and how tight they are packed together. I ended up using ChipQuik, a very small amount melted into each pad (with lots of flux) stays liquid long enough that you can remove the caps with a single soldering iron and a gentle nudge. 
 

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(Note in this picture I had already replaced C36...)

 

For the replacement capacitors I decided to use Aluminum Organic Polymer Capacitors and see if I could find smaller diameter equivalents (I could!) to make them easier to install. Here’s what I ended up with along with the Mouser part numbers:

 

   2 x 100uf - 25v - D:6.3mm H:8mm (C2, C11) - 647-PCH1E101MCL4GS

   3 x 100uf - 35v - D:8mm H:10mm (C3, C5, C9) - 647-PCZ1V101MCL6GS

   1 x 330uf - 20v - D:8mm H:10mm (C14) - 647-PCH1D331MCL6GS

   1 x 33uf - 25v - D:5mm H:5.9mm (C36) - 667-25SVPK33M

 

AB3FB651-A0D2-4F8F-8092-9C8AB75972FA.jpeg.8eb0f0a3e1cf40002cfd1221accde895.jpeg


...and partially reassembled, with my fingers crossed, it passed the start up chime test and proceed to boot just fine!

Edited by Fizzbinn
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And lastly the LCD panel capacitors.

 

The passive matrix LCD display was working pretty good from my prospective but again the capacitors would eventually go and I had already had some experience replacing caps like this on my PowerBook 100’s LCD panel.

 

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PowerBook Duo 230 Sharp LCD panel (LM64N794) capacitors:

   8 x 3.3uf - 35v - “Plastic Encased Electrolytic” (C1 - C8)


Those are the same quantity and specifications as the capacitors I had replaced in my PowerBook 100 LCD! In that case I had used size B tantalum capacitors but even with their small size it was a somewhat tight fit. 
 

After reading this post I decided to use smaller Multilayer Ceramic Capacitors (thanks @superjer2000!)

Info with Mouser part number:

8 x 3.3uF - 35V - MLCC (C1 - C8) - 810-C3216X7R1V335M6A

 

Removing the old caps showed a couple had started to leak and corrode their pads.
 

960AEC2D-50CC-4D6C-AE5C-B90332241B87.jpeg.1ad4fd88fe26c5a9f7eb1f2ecf70915c.jpegF2CC5505-1A7C-4C2E-BF09-7DC4F619DB8B.jpeg.ada4add2a7614bc82f854ecda7bc71e8.jpeg566160DA-C65B-4AC0-8EAE-2D7F8D62242D.jpeg.5df669fe1bc37d2ddd56d2e3c1a3247e.jpeg
 

...another partially reassembled test ....and success!

 

Before:

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After:

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Above pictures are with default brightness and contrast. It’s subtle but definitely improved, noticeably less banding overall in use. 
 

Re-capped passive matrix screens look pretty good to me! Wonder if the modern capacitors actually perform better than the originals?

Edited by Fizzbinn
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2 hours ago, Fizzbinn said:

I had thought about making an ABS slurry with broken bits of other PowerBook plastic and acetone but after some unsuccessful tests I decided use JB Weld PlasticWeld epoxy. I was hopeful as it specifically mentions ABS plastic compatibility. 

 

This is the way. ABS / acetone slurry is quite porous after the solvent evaporates and lacks sufficient strength for this application.

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