User talk:Wad: Difference between revisions
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(→Dissasembly of keyboard: safety first. who cares about frequency response if you've fried your laptop or yourself?) |
DumbVandal (talk | contribs) (Removing all content from page) |
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== Active Antenna parts == |
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The [[:Image:AAprototypeCloseup.jpg|ActiveAntenna board]] picture is too small/blurry to read the chip part numbers. Could you fix it or, alternately, just read off the part numbers? I think I know the big one already, the 88W8388. There are two interesting ones below that. |
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What is under the can? (maybe you can pop it right off; that works with some Marvell devices) |
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What is on the back? |
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I'm especially looking for part numbers for EEPROM and FLASH devices. |
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[[User:24.110.145.202|24.110.145.202]] 15:19, 26 December 2007 (EST) |
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== OLPC grandma review == |
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She reviews the [[Talk:Wifi Connectivity|wifi connectivity]] process. --[[User:Sj|Sj]] [[User talk:Sj|<font style="color:#f70; font-size:70%">talk</font>]] 16:16, 1 February 2008 (EST) |
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== Dissasembly of keyboard == |
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I see that you've edited the disassembly of the keyboard section to include the statement that it would not work. This is in direct conflict to the evidence which is that taking the keyboard apart does indeed resolve the sticky keyboard - whether it's due to removal of contamination or "fluffing" of the contact spacers, I have talked to 3 users that have mostly solved their keyboard problems with this procedure. |
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As long as one is out of warranty, what other recourse does the XO user have. Until you get replacement keyboards out, folks will try this process and many will be helped. [[User:Alc|Alc]] 16:21, 20 April 2008 (EDT) |
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:reply at [[User_talk:Alc]] |
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== Safety first == |
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Your supposition about frequency response is not correct. There are almost no capacitors at the front end to act with the 100k's as a low-pass filter. Moreover, the laptop's resistor value is quite low, about 1K as I recall. |
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If you make the grievous mistake of sticking the unprotected port inputs into 120VAC or 240VAC the "chassis/frame" including the port's metal shell will be come live. |
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The laptop's small-value input resistor does does not protect the input diode/tranzorb at the front end. So if you reverse a 1.5 volt battery polarity (i.e. minus into the port) you'll blow the diode. I've tested this with decent current limiting power supplies. |
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The 100K's are a very low-cost stop-gap and do not represent particularly good design. To avoid safety issues and potential damage to the laptop you should build the differential amplifier (it costs less than $10). This will protect you from frying yourself and/or the laptop up to 240VAC. There are some design simplifications and cost reductions possible that I came up with. |
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My personal rule is this: do not post anything that can mislead and result in damage to the laptop or harm to the student. Bill [[User:Wvbailey|Wvbailey]] 17:09, 30 December 2008 (UTC) |
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