Posts Tagged ‘mod’

IBM 122 key follow up (1)

April 6, 2014

Continued from here.

I decided to go ahead and order the keys from Unicomp, the quality’s ok, the color sorta matches, but they couldn’t make me custom keys.  I did get a tux key, most of my media keys, a context menu key, and another escape key.  I’m going to apply some inkscape talents to making the key labels, but I’m not sure how to go about marking the keys.  I could mask with tape and burn it off.  I could dust it with toner or thermark and try to melt it in.  I could engrave and try to wipe paint in.  I’m waiting on a part for our little laser cutter, but I’m leaning toward dusting it with laser toner and trying to fuse it into the plastic keys.

Here’s my keyboard a it stands today, I’ll add a picture of my key designs later tonight.

Next post here.

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Simple headphone splitter

June 12, 2013

my simple mod

Anyone who is familiar with computers tends to know that on the back of most motherboards is a little tower of headphone jacks.  This connector (usually 3, sometimes 5 or 6) is a nice way of bundling all the needed analog audio outputs of a computer together, but if you’re salvaging parts from an old or dead motherboard why would you take it? it has a strange footprint, it’s seldom you need 3 outputs from a project, and even less likely that you’d use it to repair another motherboard.  Here’s a simple use for it: a headphone splitter.  I personally use mine to go from my hardware master volume control to my speakers, wireless headphones, and 5 1/4″ bay speakers.  Another mod I did was to take one of these and wire it up so one was pass through, one was mono left and one was mono right.  That particular mod was nice for a dual monitor computer with speakers built into each monitor.  These connectors usually have leaf switches built into them so the audio path is disconnected and redirected out the jack you just plugged into.  The possibilities are not endless, but they’re certainly more than I have stated here.  I can post a diagram of the pinout I derived, but you’d be better off with a continuity meter and a 3.5mm plug.

LED backlighting a 22″ lcd monitor

June 12, 2013

This one’s kinda messy, but I was visiting my parents so I only brought my soldering iron and basic tools with me.  I had a friend mention that their lcd monitor was broken, of course the first thing out of my mouth was “I can fix it no problem”.  It was a little more complicated than I thought.  Let’s review the most common failure mode of electronics this decade: bad caps.  What I mean by that is capacitors that have failed, exploded, had their ESR go up, heated up due to that and then exploded, or bulged, or just plain leaked.  The reasons are numerous: there could be an unexpected cooling failure causing the caps to heat beyond their tolerances; there could be too high an ESR as I mentioned; they could even just be, gasp, old! But by far the most common reason for failure is espionage.  It’s a little more mundane than it sounds, there are news articles, wiki entries, and even a website and forum dedicated to it.  I’m just hereto say it has been a godsend for those of us that can open consumer electronics and solder reasonably well.  When you have people throwing out devices worth several hundred dollars each because of a few cents in parts that are fantastically easy to identify and fix… well, let’s just say I know some people who could major in monitor repair and minor in general debugging.

the whole setup, mountain dew and all

This problem monitor happened to be a Sceptre 22″ lcd monitor.  Now, due to the rapidity that people are throwing out monitors I tend to have a large backlog from which I can pull parts (usually entire power or logic boards, sometimes button panels, etc…) but I don’t have any spare dead monitors this big.  Once open (although I should have done this first) it was obvious that the LCD worked, the logic board worked, and the main part of the power supply worked.  I could tell because the only thing that didn’t work was the back-light   This doesn’t preclude it from being bad caps, but it lowers the likelihood   In back-lights I tend to see one of four things go wrong.  First there is the simple bad caps on the inverter input, this wasn’t the case here.  Next there’s the blown PWM chip or blown FET driver, usually SOT-8 or DIP-8, can be blown by heat, time, or voltage fluctuations (sometimes traced to caps). Another potential failure mode I know is shorted transformers; I haven’t ever gotten a monitor I cared enough to diagnose this far, but the PWM chips create a square wave that gets stepped up in the transformers to drive the high voltage tubes.  The problem this time was bad back-light tubes.  These tubes were seriously blown, though I have come across ones that glow red briefly and then the over-current protection kills the back-light inverter.  Well, I don’t have any spare tubes this size, what about LED strip lighting? that should work, right?

assembled with strips installed

I ordered a 12v LED strip off of amazon and it is pretty nice stuff.  The stuff I bought had a rubberized coating on it meant to be used outside, which didn’t really help, but oh well.  The rest of the mod went as expected, I pulled the tubes, carefully disassembled the panel and fitted the new lights, ran power wires through a switch because I didn’t feel like working out the back-light auto-on feature and powered it off of the 12v tap on the power board.  That simple, I could have done with some better diffuser  but I didn’t have much time to work on this.

monitor off, back-light on, diffusion problem

working. Next patient!

entire disassembly album

Modded slug

June 12, 2013

This is in no way an original project, but I’m publishing it because I think some of the things I did were pretty neat.  A long long time ago Linksys released the nslu2, a network atatched storage device.  That’s cool, let’s open it up to see what it has inside.  TTL level serial port, cool, I put a header on it, and broke it out to the ftdi friend standard with a pigtail though a hole in the case.  Overclocking? yes please! just remove resistor R83, it’s that simple to double the clock speed.  now you’re cooking with gas at… 266Mhz. Ok, this is a bit of an old device.  What else do we have…. more USB ports? ok, I can break those out, but first what’s with this one port that doesn’t allow flash drives? it has no power line soldered to it… what? Ok, there’s a set of pads for a fuse like the other port has, but it’s not connected.  Maybe it’s to make sure their cheap power brick won’t crap out on them? No matter, solder a jumper and it’s done, add another 3 ports and they’re all broken out.  The thing is, I didn’t have 3 nice USB ports at the time, but I did have an old USB PCI bracket that’s normally used to break out motherboard USB ports.  No problem, just grab some pin header and a scrap of PCB (these pin headers tend to fall apart if not soldered to something sturdy.  Now I have a total of five powered USB ports.  Now, about that power adapter… This thing runs on 5v, and after tracing the power rails I find that it’s unregulated all the way out the USB ports, so I dig out a monster 5a 5v supply, graft on the right barrel jack and we’re in business.

new ports soldered in, pretty cleanly

Ok, now that we’re done with the hardware (all that I did anyway) let’s move on to the software.  I’ll admit that I had modded this thing, put it on a shelf and forgot about it for a while, the only thing I remember was insisting that I had to have the most capable linux install on it (a debian derivative) and it had to be a fully featured linux box (a configuration nightmare compared to what I finally used it for).  So I have a modded slug that I want to re-mod to have Unslung on it, a derivative of the stock firmware that allows those extra usb ports.  All the tutorials say to “use this utility and it’s easy”, bah, I have a serial terminal, no need to mess around with blind boots, and all this crap.  With my experience modding FONs and other embedded linux devices I’m actually more comfortable with redboot, a tftp server and raw commands.  Following the tutorial listed here I got it installed and booting in no time.  I can’t use it as a general purpose webcam server or network connected speaker system, or whatnot but it’ll make a good NAS.

big boy

There’s another interesting feature of the nslu2 has, a strange one, a USB device port.  Now, I can’t really say what I’d use it for, but it’s there and I haven’t done it yet (I may never).  There is a mod to auto power on the slug using a capacitor (The same hack can be done with a desktop, I think) but I haven’t done that mod, mostly because I have real servers… also does this thing not respond to WOL packets?  Now, looking at what people have done, using it as a network attatched power switch and stuff, they all seem to use usb connected devices to trip FETs or relays… what about the activity LEDs? can you not manually control them like on the WRT54g or the FON?  Some pretty fantastic things have been done with these devices, as a EE I tend towards the really cool hardware, like using the I2C bus to talk to low level devices directly, adding more RAM and flash, and the fact that there is a second RX and CTS only serial port in there somewhere.  Check out the wiki, it has so much covered on this neat little gadget.

done

References:

pretty comprehensive wiki

fantastic pictures

DIY hard drive toaster

June 12, 2013

So, here’s an old one, anyone else do enough with sata drives that warrants having a way to easily and painlessly drop one in a computer?  I did,but I really couldn’t justify one of those hard drive caddys, they cost a lot more than the regular enclosures I had lying around (buy a hdd on sale, pop it open, drop it in on a sata bus for faster transfers).  The idea is pretty simple, it just has to hold the hard drive firmly and be able to be removed at a moment’s notice.  I really liked these Western Digital MyBook drives, they fit on a shelf, are easy to open and they stand up, which is important for this mod.

the finished product

Construction: cut it in half.  Well, ok, it’s a little more involved than that.  Pick a spot (probably above the light pipes is a good idea), measure it out so you have a level line all the way around, and cut the outer plastic.  Now you have the inside metal caddy to deal with, cut it a little below the level of the outer plastic to allow for a nice top to fit level.  The top came from the discarded top of the MyBook, but it curves, and mine doesn’t.  You  could curve yours right along with it, but I cut mine off right before the curve and used the bit salvaged from the back to complete the top.  Now, just cut a hole in the top the right size, slather it in hot glue and you’re done.  The reason I say hot glue is that all the methods this thing had for staying together are now compromised, like cutting the top off of acar: you need to reinforce it, or it’ll fall apart.  There you go, don’t forget the light pipe before hot gluing the hell out of it!

as you can see, I used the bit of caddy to reinforce the other side

The rest of the pictures