flicker – The Third Half

G530 Flicker Saga: The End?

Well, I hope everyone has had a great Solstice, and will continue having a wonderful holiday season with Christmas in a couple days. Up here in NY it’s been pretty rainy and a little on the warm side, with little snow. Hopefully we’ll have some for the 25th, as that would be fairly appropriate. And hopefully when the inevitable lake effect comes we’ll all be safe. If you’re reading this from somewhere out in the western US where they seem to be getting our winter weather, I wish you the best.

Anyway, as you may have seen me post here in the past, I’ve had some interesting issues with my Lenovo G530 laptop. First, the screen became wobbly and shaky. Then, it started to flicker. The first of these was easy to fix, the second very annoying, and almost as easy to fix. Well, I write now because the dreaded LCD flickering has returned. Now, it’s been a while since I posted about it last, but in truth the fix lasted for maybe three weeks. Figuring the cable had come loose, I repeated it, giving me another couple weeks. Finally, a couple weeks ago I reseated the video cable only to have reliable operation for maybe a few hours before the flashing came back. It seemed that the work around involved slapping the display repeatedly in certain locations along the sides, which served to jostle the wiring back into place, as well as relieve some of my frustration. Then last week, after doing this for a while, I got fed up with this. Here was the result:

Now, you might think that that was a little bit harsh. But, I disassembled part of the screen and put it back together again. I figured that somewhere in there something was in a bad position, and just needed to be tweaked a little. And, it worked! Since doing this I’ve had no flickering. You might be wondering what, specifically was the problem. Well, I still am too – all I did was take it apart and put it back together again, and it seems fine.

Now, given the popularity of previous posts a nice guide is in order. However, there are a few things to keep in mind before going through this and attempting it yourself:

After taking pictures, I realized that I probably could have gotten some better ones for illustrative purposes. So, I recommend that you take a look at Lenovo’s page with take-apart instructions for this unit. Also, look over the entire graphic carefully before attempting anything, just to get a general idea.
You need to first follow the instructions for getting at the screen hinges, as well as reseating the video cables. The first of these is more important. Use it to get at the hinges; don’t tighten them as we’ll be unscrewing them. The second is less necessary, but I recommend it to have easier access to the cables, and because you may as well reseat those while you’re tearing this thing apart.
There are a tone of small screws and such in this. You probably already know this if you’ve taken it apart before, but it bears restating. Find a clear, hard surface like a kitchen table to work on this, and keep track of your screws. It should go without saying that an appropriate screwdriver set is a must (though you’re probably good if you’ve done this before).
Be careful when removing the screen bevel (after unscrewing the screws under the little rubber feet). Use a small, flathead screwdriver and beware of power and data cables, as well as the camera up top.
This isn’t a bad time to clean the laptop screen while you’re at it. I used a paper towel I dampened, and added a drop of dish detergent to it. Try not to get and soap or water into the sides of the display. Take another damp paper towel to rinse it.
Finally, this procedure is a bit more involved than ones before. So, BE CAREFUL. If you aren’t comfortable doing this, seek assistance. And of course, do this at your own risk; I am not responsible for any damage to your laptop, yourself, or any other possession.

So, here it is:

Good luck. This may help you, or it may not, but if the flickering has really been getting to you it’s worth a shot. Overall, if you’re thinking of buying a G530, I’d recommend against it. It’s pretty nice for a crappy machine, but it is a crappy machine. But if you’re stuck with one, at least it’s not impossible to take apart.

Lenovo G530 Screen Flicker

Well, I have no doubt that my trusty Lenovo G530 will still be functioning after the rapture. It’s getting a bit flakier in its old age, but it’s still chugging along quite well. However I do, of course, have to tend to it from time to time.

If you have one of these you might have gotten the telltale flicker of the LCD screen. Sometimes this seems to accompany the loose screen hinges. Well, it is slightly related; this problem is actually caused by a loose video cable leading to the monitor. For me, it wasn’t actually that hard to fix, basically amounting to a connector that needed to be reseated. (Another cause could be the cable itself, which would be bad, but it’s probably just the connector.) To fix it, just remove the keyboard, disconnect the video connector, and reconnected it. Once again I have prepared a handy graphic to guide you (though be sure to check out my post on fixing the screen hinges and check out the graphic there first; you’ll need to take those steps to get to the screws here):

Be very careful, as the parts in here are kind of delicate. Particularly don’t yank the keyboard too much. Pry the video connectors out with a screwdriver (carefully), and then just stick the back in. The problem could be as simple as crud on the contacts, and just doing this can work wonders.

This fixed the problem for me, your mileage may very. Of course, do this at your own risk (ie, I am not responsible for damage to your laptop), but if you’re careful there’s not a lot to mess up.

UPDATE: This may not fix the problem permanently. If the problem comes back and maybe even gets worse, I have a new post with a solution that may be a little more effective.

The Flicker Circuit

A while back I posted about a circuit I had devised that would make a lightbulb flicker such that the light it cast would resemble a candle flame. You see, last Halloween I was living in my apartment on RIT, where fire is not permitted. So I began to comb around a look for a circuit online that would make a normal light bulb flicker in this way. There are some floating around, but after a while I decided I wanted to build my own. I did, and it works pretty well. I was going to post a schematic, but it was something I kind of put together on a breadboard, and didn’t have a diagram handy. I was going to make one and post it, but I forgot about it. For a while. Well, now I do indeed have a schematic, having just thrown one together. I am posting it here, and you may use it for personal or educational, non-commercial use. Here it is:

The circuit is meant to run on 12 volts; if you’ve checked out some other posts you’ll find I’m a bit of a solar power nut. I figured low voltage is relatively safe for this sort of thing, and I had 12 volts handy anyway from a gel cell, so it works out. (A wall cube supply would also be great.) The light also must be 12 volts; I’m just using a small 1/4 amp bayonette bulb I found at an electronics store (it works well in a Jack ‘O Lantern). The bulb is driven by MOSFET Q1, an IRF720. It can handle a lot more, probably a couple amps, but you’ll need a heatsink for it. The bulb I use doesn’t make it heat up all that much. Basically this circuit is kind of like a light dimmer. You’ll notice it uses three 555 timers, that tried-and-true timer IC that’s been around since forever (the 1970s). These have lots of pages associated with them scattered around the Internet, so check Google for the fine details. But basically timer U1 is a PWM light dimmer – we use it to turn Q1 on and off really, really, fast (around 1 kHz), and we change the duty cycle (the percentage of the time it’s on) according to how bright or dim we want the light.

To control the dimmer, we use two other 555 timer driver circuits. These control it via Q2 and Q3, which add resistance and thus change the brightness. Q2 and Q3 are controlled by U2 and U3, which turn them on and off. By doing this at much slower rates (they must not be exactly the same, but close), different levels of brightness are acheived. Because the rates are different the light cycles through the pattern. It’s not truely random, but it looks close enough to the casual observer, making it pseudorandom.

Now, you could play with R5, R6, R7, and R8 to get different rates, and maybe make it a little more realistic. You could even stick potentiometers in there if you wanted to adjust it. But you’ll probably be fine with just experimenting with different values until you find something you like. (Again, I won’t go into it too much, as plenty of info is available on the Web. Also, it’s late, I’m tired, and I don’t feel like thinking about it too hard.) I suppose you could also build upon this concept and use it to drive something like a thyristor and control an AC bulb. (Be careful when working with high voltages; you do it at your own risk.) If the one bulb’s not bright enough, you could also add more in parallel. They would all flash the same, so it would work. You could add more dimmers and more driver circuits for different combinations, if you wanted to drive a bunch of pumpkins and not have them all mysteriously flicker in unison.

Or, you could just use a real candle.

Halloween Weekend and Election Day

I went home this weekend again. Here are some pictures:

So yeah, expect a schematic for that flicker circuit whenever I feel like it. I actually came home for Halloween, and so didn’t need it, but it’s still kind of neat anyway.

Well, on another note, remember to vote tomorrow. We don’t get many opportunities to take a slice of democracy in this country, but it is our country, and we deserve a say.

Flicker Circuit Preview

Well, the flicker circuit I alluded to earlier is done. It’s on its own project board, and it does in deed make a light bulb flicker like a candle flame. Unfortunately, I don’t have a schematic to post at the moment. I’m not sure if it will make a difference at the moment, especially with Halloween in a few days. Yes, I’m sure it would be useful for other decorations or whatever, but a pumpkin light is a good application for it.

Well, for those of you a bit more electronically inclined, I’ll explain how it works. It’s probably not the best way to make a light flicker, but it works for me and is pretty convincing if you mess with it. First, consider a circuit that dims a 12 volt bulb. A way this could be done is using a 555 timer to switch a MOSFET on and off really fast – PWM. So, you change the duty cycle to change the brightness of the bulb (ie, the bulb is dimmer when it is off more than it is on, but it’s still switching on and off so fast you only perceive it as being dim). I based this part of a circuit off of a light dimmer I found in Home Power Magazine Issue 34 (I think), though you should be able to find something like it online. (If you are not familiar with Home Power, check it out. It’s great magazine on renewable energy, though a lot of the juicy electronics type stuff is in the back issues.)

The circuit I mentioned runs at around 5 KHz (I recall; I don’t have the specs in front of me). Now, think of another 555 timer circuit, this one with a much smaller frequency, maybe a few Hz. In other words, imagine an LED blinking noticeably. Now, think of a nother one, but with a slightly higher or lower frequency.

My circuit uses the two 555 timer circuits I just mentioned, as well as the dimmer circuit. Basically, the two circuits flashing at a few Hz switch resistors on and off on the dimmer circuit, causing the brightness of the bulb to change. With both circuits going at once, there are a few different levels of brightness the bulb can be at. Technically the patter is not random, but it does look that way to the casual passerby. I believe the term for this is pseudorandomness.

Right now I have this working for a 12 volt DC bulb. For something like a 60 watt 120 V bulb on AC, search around. There are some other ciruits I found in the quest for finding a nice one for a low voltage bulb. The MOSFET I used can tolerate I think around 20 amps, though I only use it with a bulb that pulls about 200 milliamps. If you want to use a bigger bulb a heatsink would be a good idea.

I’ll try to get a schematic up soon. Until then, maybe someone can come up with a similar circuit.

Snow

The other day (two days ago technically, since it’s after midnight right now), we got snow. It wasn’t really that much, just a few little specs that melted on contact with the ground. My roommate says it was sleet, but I believe sleet means rain and snow, and at that moment I think it was just snow. So that was the first snow of the season.

Today we actually got some respectable amount of snow. Rain too later on, but there was definitely some snow. It didn’t accumulate much, but it was decent. It’s funny, as two years (and a week or so) ago my hometown of Buffalo got hit with a storm of apocalyptic proportions. It knocked out the poiwer to my house for a week, but luckilly my parents had a generator. The trees along my street had their branches decimated too. It really wasn’t a lot of snow, but it came fast.

Who knows how this winter will be. But this fall is looking pretty good. It’s cold out, which is nice, and the trees are looking really beautiful. My only gripe is that it’s a little cloudy. Even that’s not so bad, at least not until late winter when it seems like it’s always dark.

I’m still working on my light flicker circuit, which I hope to have described in more detail here by Halloween, but I’m not sure if that’ll happen. Well, whatever. It’s a neat circuit, and really makes a light bulb flash like a candle convincingly. Problem is, when I put it together on a project board I found that it shorts somewhere. Oh well.