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[redstudio]

I wonder why so many PowerBook G4s don't have working internal speakers. I own 4 of them and I bought them with non-functioning internal speakers, audio only with headphones. Reading around, it seems like a very common problem. Why? Is it possible that after a while the internal speakers break? And yet they don't have to handle high volumes... Could it be a software problem? Firmware/hardware? Can the situation be fixed? Let me know if you know anything. Thanks!

[DrNo7]

Just a 2 cents guess: all Powerbooks are 20+ years old. The membrane of speakers becomes brittle with time and no membrane=no sound.
However, I wonder if these speakers are close enough to off-the-shelf references or if it is Apple unicorn parts that will mean surgery to adapt (or a pair of amplified computer speakers at a thrift store to be simpler and period correct 😝)

[robespierre]

The rubber surround of a dynamic speaker (the part that crumbles) doesn't produce the sound. Its function is to create an air seal around the cone to increase the efficiency and reduce rattling noises.

Like many electronics d'un certain age, the problem is electrolytic capacitors.

[wove]

I restored a 2005 17 inch G4 Powerbook about a month ago. After having it back together there were still a couple things that needed attention, one of those things was no sound. I checked the wiring harness and the connections, but the speakers remained silent. I found a set of speakers in my parts bin and replaced the non-working speakers. It appears that the speakers were what was bad, for the speakers from the parts bin work just fine.

It does seem odd that speakers would just fail and the problem with the original speakers might still be in the connecters or wiring harness. In my case though replacing the speakers did correct the problem.

[redstudio]

Thanks for the information. It's already a good starting point and gives me hope! In fact, the sound card capacitors aren't electrolytic but ceramic, so they shouldn't have the same defects. Is it possible that so many PowerBooks have no sound? Is there a manufacturing defect in the speakers? Are the coils drying out and not moving anymore? Would there be any noise? Are they burning out? It's a mystery.
Next time I disassemble one, I'll try to extract the signal from the one that should be going to the speakers to see if that's the case with mine too. It's certainly impossible to find new originals. Used ones are likely to be faulty. We'll see. If you have any other experiences, let me know. Thanks!

[GaryN]

I'm going to hazard an educated guess here that the speakers got blown by being played at or near full volume. Even the tiny chip amps used in laptops are capable of delivering a surprising amount of voltage when driven into distortion. This seems far more likely than the speakers just "dying of old age"…

[redstudio]

It's a good hypothesis, but the percentage of PowerBook G4s (17-inch aluminum series) without audio and internal speakers is very high. When I look at ads for the 17-inch model, almost all of them are "laptop in perfect condition, no audio." Is it possible that everyone listens to music at full blast on their PowerBooks? My laptops were purchased by people who used them mainly for graphics, office work, even older people. The only one I bought that had an iTunes playlist inside was on a titanium model, but the speakers work fine. I also have a very old G3 Wallstreet, and the speakers work fine. Perhaps this is a problem only with the aluminum G4 series? Does anyone have audio problems with other models? I agree, too, that I don't think the speakers die of old age.

[wove]

So many G4 Powerbooks one comes across today, have suffered more damage from incompetent repair/upgrade work than damage from general use. The cosmetically visible parts of the 17 inch G4 I worked on were overall in very decent shape. But it had torn cables, broken stand-offs, bent flanges, and stripped screws. Everything was then dumped back in the body, taped together and sold as part of a lot of "for parts" machines. And the remaining 4 units in the lot are in the same condition.

Generally I look for machines that are listed as "found in closet-garage-attic" unknown condition. They tend to be simply abandoned machines and although typically very filthy, they are often the best bet to become nice working machines again.

[ovalking]

>Does anyone have audio problems with other models?

No sound on my PBG4 800 (Titanium 15"). Just one of many problems on this lemon of a machine. Ligh non-travel use, never taken apart.....

[GaryN]

I forgot to add that oftentimes people eff up the headphone jack by breaking off a cable/connector in it then prying out the broken end. THAT can and does kill the audio output by breaking the jack.

[redstudio]

In summary, we found these causes:
1) speakers
2) capacitors
3) cables, poorly maintained
4) headphone jack
My thoughts on my PowerBooks.
Three of my PowerBooks have never been opened, so I can rule out poor maintenance. Regarding capacitors, you need an electronics engineer to check sound cards; I'm not capable of doing that. As for the headphone jack, I can say that in the "sound" control panel, inserting and removing the jack is correctly recognized by the system, displaying the jack/speakers switch. Perhaps I would rule it out. Are the speakers subjected to high voltages? Being laptops, are they subjected to mechanical stress? Indeed, even the initial "boom" sound when turning on, if set high, could be a real blow to the small speakers. Are the speaker cables prone to detachment over time and with movement? Everything needs to be verified. Maybe it's all of these elements or just one in particular. The fact remains that too many Apple laptops don't have audio. As soon as I have some time I'll try to check these out. Thanks for giving me ideas on what to look for!

[redstudio]

I think I've solved the mystery of the PowerBooks with no sound; it's the faulty speakers. Of three laptops I've opened, they're the ones that don't work (tested), and the reason lies in their construction. Normal speakers use a paper or plastic cone with a rubber surround, which usually wears out or decomposes over time. These speakers have a rubber cone and surround! Of the three I've inspected, two had cracked rubber that prevented the cone from moving. One moved, but the rubber was flaking, and the voice coil got stuck. I think the problem with the voice coil has burned them out over time. If they were installed in all aluminum PowerBooks, they're definitely not going to work anymore. what a strange choice to use rubber for the construction of everything which is the only element that deteriorates in classic speakers.. however ordered in plastic (found similar product of dimensions.. 2 cm original 4 ohm 6w unobtainable, taken 8 ohm 1w they will sound half, but for test..) tried to replace them in a test powerbook.. it was exciting to finally hear the initial "boing"!

[redstudio]

broken speaker

[redstudio]

new

[robespierre]

Good catch! You can find burnt-out voice coils by measuring the terminals with an ohmeter. A 4-ohm driver will be around 3.5 ohms at DC normally, but "+OL" if it burnt out.
The rubber diaphragm may have been chosen for a lower resonant frequency vs a plastic cone, but we now can see how they degraded with time.

[aBc]

Hey redstudio, I cropped and downsized your images for easier viewing (hopefully without the need for scrolling). 

And... where did you source the new speakers? [For those that might also wish to replace theirs in a similar way.]

*I've three 17" G4 PowerBooks... and lucky I suppose, all have not yet succumbed to such rot.

[ssp3]

what a strange choice to use rubber for the construction of everything which is the only element that deteriorates in classic speakers..

Nothing strange here at all.
A bit of insight into speaker chassis design... Primitively speaking, to get the good bass, you need the low resonance frequency of the speaker. Soft surround (foam, rubber) gets you low resonance, stiff surround (paper, plastic) gets you high resonance, but, as a result, no low bass.
It's obvious that Apple went for good sound in their, exensive at the time, portables. Nobody thought about longevity back then.

https://en.wikipedia.org/wiki/Thiele/Small_parameters#Qualitative_descriptions