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Brad Fitzpatrick

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Missing AC adapters [Oct. 16th, 2005|12:49 pm]
Brad Fitzpatrick
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[Current Mood |exhaustedexhausted]

I have a dozen bins of electronics, sorted by function:

-- networking
-- phones (cell and land)
-- audio
-- power cords (extension & computer) & strips
-- power adapters
-- computer

Each one is overflowing with nicely labeled plastic bags, often listing the length of the cord (if ethernet), and the voltage and amperage (if an AC adapter), etc. It's a pretty good system. The plastic bags are the trick... without them it's a rat's nest of interlocked cables, and the system's useless.

Today dina finally got annoyed by no wireless in the house (I've never set it up) and asked I set it up.

No prob, right? I probably have enough cat-5, switches, and WAPs to network the whole neighborhood.

Yeah, but I can't find a working AC adapter. I need either 12 VDC 1.0A or 5 VDC of unknown amperage. I found the 12 V one, but it doesn't light up the WRT54G and just ends up getting really hot. I went to test it with a voltmeter, but the battery(!!) to the voltmeter is dead. Why does a voltmeter need a battery to measure voltage? Useless. And it's some bizarre non-standard battery.

Scratch that --- on to the 5V WAP11. But I can't find any 5V AC adapter around here except for three that are 1.2A and don't fit.

Went to look online to get a new AC adapter... $9 + $9 shipping. Hell if I'm gonna pay $18 for a new wallwart. I can get a whole new WAP for like $70 at Central Computer.

I don't know any electronics surplus stores around here. Surely I can go somewhere local and buy an AC adapter?

[User Picture]From: jgrafton
2005-10-16 07:55 pm (UTC)
If you have a Radio Shack nearby you might try it... not sure how much it'll cost you, but they should have the adapter you need.
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[User Picture]From: cheesedip
2005-10-16 07:57 pm (UTC)
second both suggestions. even small hardware stores are likely to have ac adapters, if there are any in your neighborhood you might want to check them first.
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[User Picture]From: henry
2005-10-16 09:54 pm (UTC)
I've got a couple different multi-voltage adapters from there that will power just about anything in the house. Definatly the easy way to go.
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[User Picture]From: nolegs
2005-10-17 01:11 am (UTC)
Everything at Radio Shack is free man. Their security camera layouts are juvenile and their salespeople too easily distracted.
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[User Picture]From: boggyb
2005-10-16 08:03 pm (UTC)
I went to test it with a voltmeter, but the battery(!!) to the voltmeter is dead. Why does a voltmeter need a battery to measure voltage?
If it's a digital voltmeter, then the battery powers the display and the gubbins inside. The point of that is to draw as little current as possible from whatever you're measuring the voltage of to minimise the effect the voltmeter will have on the circuit or whatever.

If it's an analogue one, then it shouldn't need a battery to measure the voltage as they usually work by feeding the input through the coil for the display movement.
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[User Picture]From: dorkmatt
2005-10-16 08:07 pm (UTC)
Ditto on Fry's (tho you'll only find nakid "universal" wall warts easily).. surplus'y stuff comes in the form of Surplus Computers (in Santa Clara off of 101, formerly Software-n-Stuff), HSC (also in Santa Clara) or Weirdstuff Warehouse. All the good surplus places in the area closed years ago (RJ Enterprises - place with the big red UK style bus, Quement Electronics, etc - so sad).
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[User Picture]From: jwz
2005-10-16 08:11 pm (UTC)
So now you're up to $10 for the wallwart, $12 dollars in gas for the round-trip down to the Blighted South Bay, two hours on the freeway to get there and back, and a bonus anal-cavity search at the Fry's door. Just fuckin' walk down the street and buy a new WAP, dude.
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From: qmrq
2005-12-14 01:33 am (UTC)
What's this about Fry's security?

Someone please elaborate.
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[User Picture]From: perpetualmotion
2005-10-16 08:15 pm (UTC)
I have a spare WRT54G lying around (just replaced it with a WRT54GX2 because it was starting to behave oddly) so I have a spare AC adapter for it :) Let me know if you want it, or if you want me to describe it to you so you can look for it (it's from Delta Electronics, I believe).
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[User Picture]From: scsi
2005-10-16 08:18 pm (UTC)
I gave whitaker my old one, I wonder if he took it back home with him.
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[User Picture]From: xaosenkosmos
2005-10-16 08:23 pm (UTC)
Why does a voltmeter need a battery to measure voltage?

Because you usually need a reference voltage to measure against?

There's an awesome surplus place near the Fry's in ?Mountain View?. I can never quite remember where it is or the name of it; midendian was nice enough to take me there once. They've got just about everything you could want, including a Z-80 ICE =)
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[User Picture]From: dakus
2005-10-16 08:40 pm (UTC)
I think I have a universal in my garage I'm not using...
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[User Picture]From: notjohndavid
2005-10-16 08:53 pm (UTC)
heat is bad mmmk.

since you're dealing with VDC you also have to worry about if it's center pen positive or center pen negative (look at the little diagram that looks like a tie fighter... almost)

you could always hack one together if you have some odds and ends that you aren't going to use.

like say you have a 5VDC wart that has the wrong end and polarity.... and another that has the right end but the wrong voltage (and amps aren't a problem as long as it's >= needed) cut and splice... electrical type styleee

i do that a lot but i'm ghetto
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From: legolas
2005-10-17 11:21 pm (UTC)
That's also what I was thinking with the no lights but is getting hot part: reverse polarity on the pins. If it says V and Amps, it may also have a drawing of which is/should be the positive one. And if not, you may get lucky and the manufacturers sites? (ok very lucky)

If you wanna go really hackish, hook up the volt meter with the right amperage from another battery if possible (just wire it).
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[User Picture]From: ch
2005-10-17 04:27 am (UTC)
a voltmeter presents a very high impedance (ideally, infinite) at the probes. as such it draws very little current from the measured nodes. so to drive a meter or a digital display, you need additional power.
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[User Picture]From: jackbrinks
2005-10-17 07:45 pm (UTC)
Christ, tell me you don't actually stop for those clowns at the door at Fry's. They don't have that right. Walk right past them.
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From: photwenny
2005-10-23 12:08 am (UTC)
Dude! But they mark your receipt with a pink highlighter. Its important, ya know! ;)

If there's no line, I'll slow down to let them do whatever it is they think they're doing. If they are occupied with someone else I don't wait.
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