I've been given an IBM 6643-13U, aka "NetVista X40" all-in-one. I've been told by the previous owner is has intermittent sound functionality.
(sound is SiS 7018)
This unit has an integrated sound card which, because of the case design, is wired to two berg connectors: one for the built in speakers, one for the headphone/microphone/line-in jacks.
All wire connections have been verified with a multimeter...there are no broken connections outside of the motherboard itself.
System beeps do play through the built in speakers.
The machine originally shipped with 98SE, came to me with XP SP2. No sound in XP SP2 so I tried a clean install using drivers from IBM's site (for 2k, but xp/2k use near-identical driver models), no luck.
Tried a clean install of 2k SP4, IBM drivers, no luck.
Have also tried Windows Update drivers for sound, no luck.
Funny thing is, you know how you can test the volume by single clicking the volume icon, then clicking the slider bar, and it'll make a noise? Instead of playing the noise, it makes a system beep, which usually indicates the drivers are not installed...
During startup, when the drivers are initialized, the speakers make a gentle "pop" sound, as is normal, suggesting the sound card should be working. All issues for the built in speakers are the same for the headphone jack (that is, there is no difference between the two).
Originally I thought maybe the headphone jack was somehow jammed inside, turning off the speakers, but since the headphone jack has no output also I don't think that could be it.
I can't figure this one out, so maybe someone else can. Google doesn't reveal this is a common problem for this model.