Blake doesn't have a personal statement currently.
32 years old
Music, cycling, software
Joined: 28-January 08
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Last Seen: 16th February 2008 - 11:51 AM
Local Time: Apr 30 2017, 09:24 PM
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15 Feb 2008
Well, my Z doesn't charge it's battery anymore. It's my fault; I was experimenting with an alternative power source for the Z (a USB hub powered by a nice bicycle generator) and failed to exercise the sort of caution that something as beautiful (and pricey) as a c3000 deserves.
I compared my experimental power source with the power adapter that came with my USB hub using a volt meter. I am certain that I got the polarity and voltage correct. The rest is speculation on my part, I am not an EE and I was experimenting way outside my expertise as a programmer and a cyclist.
I hooked up the alternator's output (the frequency of this AC varies with the speed of the bicycle wheel and goes very low, maybe 10hz) to a bridge rectifier. This rectified DCish voltage I fed into a switching DC-DC converter (DE-SW050) which outputs 5v and can take up to 30v input. That 5v is powering a USB hub. The DE-SW050 has two capacitors built in, but I guess they are too small to smooth out the ripples when the frequency is low (the datasheet claimed 2% ripple which shouldn't hurt anything). The blue LED in the USB hub flickers visibly, which should have given me pause for thought. I guess I didn't think carefully about what rippling voltage might do to something expecting smooth DC.
I observed that this setup charged my least expensive USB device (an iPod nano) successfully. Here's where I acted hastily out of excitement: I plugged in the Z and went for a ride. After that, the Z does not seem to charge batteries. The charge light comes on, but I left a dead one in there over night and the Z didn't turn on in the morning. That was stupid. Oh well, live and learn. At least the Z still works.
Anyway, two questions:
First, I've read somewhere on this forum that there is such a thing as an external BL-08 charger but haven't been able to find one. Anyone know where I can get one in the USA?
Second, does anyone have any idea which part I might have damaged (possibly a regulator that I cooked with too much current) or where it is on the board? Or any thoughts at all from an EE? I'm pretty much stumped and I'll probably just have to settle for charging batteries externally.
I opened the Z up and looked around, particularly near the power-related stuff. I couldn't see any evidence of damage.
This forum has been very helpful. Thanks, everyone!
29 Jan 2008
First, I apologize if there is a better forum for this question, but I've googled this a bit and found little discussion on the topic.
I got a c3000 recently and put Angstrom on it. It creates a 32Mb ramfs on startup, just like my old 5500 did.
I remember from my 5500 days that OZ would build a selection of kernels with different sized ramdisks.
I want the other half of my memory available. Will I need to build my own kernel for that? Is there a way to simply unmount that ramfs and free that memory?
Who out there has 64Mb available on his/her Z (with an EABI 2.6 kernel)?
Thanks for your help.
29 Jan 2008
I damaged this 5500 by connecting the wrong polarity to it. From what I've come across googling that subject it sounds like it might be made to work again by replacing some component of the charging circuitry. If you have another way of charging the battery it might turn on and work (I have no way to test that). In its current condition the battery does not charge and the device doesn't turn on. Perhaps someone would like it for parts?
Anyway, I have a new c3000 and have no desire to tinker with my old 5500. Therefore I am offering it to anyone who might want to pay the shipping cost from Arizona. I don't have the original Sharp wall charger, or a working battery, or a stylus. The screen looks good though.
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