Pulster fixe(s) and rework
andy at openmoko.com
Thu Mar 5 18:51:30 CET 2009
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Somebody in the thread at some point said:
|> I have suggested a refinement on the second approach: short the small
|> capacitors. Add big caps outside the shielded unit - there are places
|> with room. But don't put wires from the caps into the shielded
|> unit. Connect them to the headset plug instead, and break the plug's
|> normal connection to the circuit board. This approach won't pick up any
|> more buzz than the headset based solution, or the current bassless
|> setup. And you can use any headset you want.
|> The big question is - is it safe to short those small capacitors? Or
|> will that have other side effects, such as draining the battery or
|> disturbing sound on the built-in speaker?
There are a couple of 1K resistors to 0V that will then connect directly
~ to the amp outputs all the time before the new DC blocking caps you
will add back in. But thanks to some recent patches by Mark Brown on
andy-tracking, we should keep the amp turned off more often.
|> Another question - is a single big capacitor enough, if it is put into
|> the ground line instead of having one cap for each of the stereo
|> channels? Or will that wreck stereo sound? One could then use a even
|> bigger cap.
You'd need to do both channels; the one with the unchanged cap will
sound the same as always otherwise.
|> There is lots of easily accessible room next to the battery, above the
|> SIM card.
| I'd love to see a good answer to those questions. Currently, it's
| unusable as an MP3 player and that's an important use for me (if
| I could use it as an MP3 player, I'd carry it with me that much more
| often, which would in turn increase my use of it).
Lifting the can and meddling with the caps is nontrivial. Somebody did
give this plan a go on the list about 6 months ago and reported some
success though. But I don't recommend considering it unless you are in
an experimental frame of mind and can deal with the fiddling and risk
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