PB3400 wont start

[3lectr1cPPC]

Well, that is likely true for audio gear. Don’t know much about it but I do know that cap quality and type can matter a lot. There’s nothing wrong with going all electrolytic, but do keep in mind that there’s basically no instance of electrolytic caps staying in spec over periods of 20+ years. Not all leak like the late 80s/90s ones can, but I’ve heard accounts of electrolytic caps as new as 2009 era already being out of spec. Tantalums stay working a lot longer. They usually fail short, where they might explode a bit, but in most cases, instances of this are rare, and won’t happen till they’re at least 30 years old, so I prefer them. Most of us do use tantalum caps when recapping. Those who use electrolytics usually do so because they prefer an original look to the board, not any other reason. I certainly don’t know much about the nuances of capacitor type though. There’s a lot of stuff like tolerances, heat, ESR, etc. that can be important depending on the type of circuit (like audio gear especially I’m sure, and in power supplies).
What I can say is that after the recap, my 3400c does have an extremely minor audio issue that wasn’t there before. I described it on my website, basically, it can distort a bit for a second or two when it’s starting up, but only sometimes, and by the time it’s booted it’s always gone. Could be related to the caps I used, no idea. It is quite literally so minor though that I do not mind it a bit, and would use the same caps again on another system.

 

[MacUp72]

I think that audio distortion at start is related to the caps on the powerboard..10 years ago I did a scratch build of an guitar tube amp, basically a Marshall JCM800..very high voltages present, not an easy job, but it worked ..I doubt that I could do that today, haha. There you could identify problematic caps in the power section because of bad filtering which resulted in audio distortion.

 

[MacUp72]

ok, I disassembled it again and this time I managed it to get the board out of the chassis..actually it is quite easy and exactly what the manual says. I followed this guy on YT ( its the only complete disassembly online I found) .
The key is to somehow wiggle the board a bit, up and down, free the audio ports on the left side, then slide it towards you (not sideways).

here some reference photos for you. ( I left the photo size unaltered)






interestingly, you actually can remove the thin metal housing of the PCMCIA cage if you just push the 2 tiny metal latches that stick through the board and hold them..then slide it off .

today my caps arrive, I hope it lives again..

 

[MacUp72]

well well, another 3400 parts machine came in..swapped the boards and now..
the second machine was a 200 Mhz model with an ethernet card, nice.
have to fiddle a bit with it, it has some problems, but hey..

 

[3lectr1cPPC]

Nice! Good to see you found one that works. They're nice laptops, enjoy it!

 

[MacUp72]

now it started to make an aweful scratchy white noise on bootup..strange

 

[3lectr1cPPC]

One of my boards has some intermittent audio distortion for a few seconds while it's booting, only after I recapped it. I suspect it's a cap I used that isn't quite right or flux residue is causing a problem.
White noise though? Does it still boot, but with the noise?

 

[MacUp72]

it is not recapped at the moment, I wanted to do everything stock with that working power board, comparing voltages etc..
ok, I did a few pram resettings etc, then it started with a deep chime, never heard that sound before, deeper, slower.
lol. Doing a fresh 8.5 install right now..

 

[3lectr1cPPC]

Sounds like funky power board or PSU to me…

 

[MacUp72]

at the moment the board is at an ultrasonic cleaning service, I dont have such a cleaner as I didnt have a use for that untill now, and equipment is not cheap, also for better soldering.
this is how those slower chimes sound like ( maybe it is power related ?)

normal
View attachment normal.mp4

slow
View attachment slow.mp4

slower
View attachment slower.mp4