Managed to trace down the +5V and ground pins for certain on that damn resistor network. Started building the replacement network board today.
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/100_2598.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/100_2597.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/100_2599.jpg[/IMG]
Need to double check the rest of the lines before I solder the rest down. This could get nasty.
Edited: Finished it!
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/100_2600.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/100_2601.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/100_2602.jpg[/IMG]
That looks fucking neat, good job man
Pro-MacGuyver'd, I give you kudos MIPS
So some years ago my parents replaced the kitchen 19" flatscreen TV because the picture was starting to get sort of wavy, not incredibly noticeable but irritating nonetheless. I took it since wavyness aside it was still working and had a VGA port.
Some time later I cracked it open looking for faults but knowing terribly little about circuits or TV's I basically just looked for scorchmarks and exploded capacitors.
I found nothing and it ended up in a closet, recently I had a late night brainwave and realized it might be the power supply. It has an external power brick so that the TV can be easily used in like a caravan where you have 12V unless you're at a trailer park. First thing though I connect the 12v rail of a PC PSU to the TV and hook up my laptop to it, sure enough no wavyness. Following that, I connect the power brick to the oscilloscope and theres noticeable noise plus a disturbingly large spike every once in a while. I crack it open and inspect it and where I expected to find a filtering cap is a 1N4744 15V zener diode.
Is there a good reason for this or did they just cheap out?
cheap out
[QUOTE=DrLuke;35064713]cheap out[/QUOTE]
Good to know. While waiting for a reply I replaced it with a 1000u cap that fit and the noise is significantly reduced but not gone entirely (~50% reduction I think, forgot to write down actual values).
I just tested it with the modified PSU and the wavyness is gone though I spoke to dad and the reason they replaced it was cause the TV tuner wasn't working, guess I got a new project.
But hey, fully functional backup monitor, awesome!
The winners of my postage only PCB giveaway are:
Subby
DrLuke
marcin1337
I should be able to take orders by the end of next week.
Yay!
[t]http://i.imgur.com/PaN75.jpg[/t]
First attempt was kind of a major cockup, the photoresist did not spread evenly so next time I'm going to spin it while drying, the exposure was either too short or my developer is shit.
Etching worked quite well however.
Hopefully second attempt will give better results.
[b]Edit[/b]
Turns out I need to mix my developer with NaOH as well, off to ebay I go.
[img_thumb]http://dl.dropbox.com/u/64443729/HPIM0572.JPG[/img_thumb]
I (hopefully) made a 24V psu. Testing it tomorrow.
I think i'll better redo the connections when i get some new tin, i really did a messy job on this.
[QUOTE=0lenny0;35080549][img_thumb]http://dl.dropbox.com/u/64443729/HPIM0572.JPG[/img_thumb]
I (hopefully) made a 24V psu. Testing it tomorrow.
I think i'll better redo the connections when i get some new tin, i really did a messy job on this.[/QUOTE]
If that's mains coming in on the left, you've got your rectifier/filter on the wrong side. Also, nothing is soldered properly or insulated or mounted. And I'd avoid using a disposable plastic food container as an enclosure on something like this.
Sorry to be blunt, but mains electricity is serious business. You should really start over from scratch with a proper case, a good iron and new solder/flux. Or work on some low-voltage stuff, then come back to this when your construction skills have improved.
[QUOTE=0lenny0;35080549][img_thumb]http://dl.dropbox.com/u/64443729/HPIM0572.JPG[/img_thumb]
I (hopefully) made a 24V psu. Testing it tomorrow.
I think i'll better redo the connections when i get some new tin, i really did a messy job on this.[/QUOTE]
I love the enthusiasm and by all means keep at it, we all had to start somewhere but...
This is just plain unsafe, if you don't electrocute yourself on that you're bound to start a fire somewhere. Not to mention it won't work cause it's rectified before the transformer as Robo donut said.
Don't lose heart though, it's a valiant first attempt! At least you got the components right, if in the wrong order...
Check out some books on the basics of electronics and as a tip, avoid working with mains until you really know what you're doing, that stuff's potentially lethal!
What the fuck am I looking at, as Robo said you've completely done it wrong.
Don't play around with mains until you [b]really[/b] know what you're doing, either your going to get shocked or you will cause a fire.
The only time having a transformer out like that is acceptable is when the primary input is fully insulated.
Also don't use freeform construction like that, get some pad / strip board and solder it all down, otherwise it's going to look like a total mess (which it does) and greatly increase the risk of shorts.
[b]Edit[/b]
I rated you zing since you're going to be in for a shocking experience.
I believe that i understand my mistake. I should first go through the transformer and then connect the diode bridge. I understand that it is a mess, all that i usually do is swap components such as replacing a capacitor. I admit that i am kinda ashamed of it but i'm in need of a 24V DC psu so i figured that i could try to build one myself from some stuff i got laying around here. I also plan on using a different enclosure once it's finished. I thought about just vacuum forming one.
Also i have been working with main power before as i learn how to build infrastructures at school, but we only see a very small amount of stuff about electronics themselves. I might sound like a fool when saying this(i hope not) but i don't expect any of these parts to cause to much harm as i always test stuff outside with a small separate fuse box(don't know if i'm using the right word for it) which should offer protection against short circuiting.
I'll give it another try later.
Thanks for the heads up!
[QUOTE=0lenny0;35081319]I believe that i understand my mistake. I should first go through the transformer and then connect the diode bridge. I understand that it is a mess, all that i usually do is swap components such as replacing a capacitor. I admit that i am kinda ashamed of it but i'm in need of a 24V DC psu so i figured that i could try to build one myself from some stuff i got laying around here. I also plan on using a different enclosure once it's finished. I thought about just vacuum forming one.
Also i have been working with main power before as i learn how to build infrastructures at school, but we only see a very small amount of stuff about electronics themselves. I might sound like a fool when saying this(i hope not) but i don't expect any of these parts to cause to much harm as i always test stuff outside with a small separate fuse box(don't know if i'm using the right word for it) which should offer protection against short circuiting.
I'll give it another try later.
Thanks for the heads up![/QUOTE]
Mains -> Fuse -> Transformer -> Diode Bridge -> Capacitor -> Output
[QUOTE=0lenny0;35081319]I thought about just vacuum forming one.[/QUOTE]
I'd really recommend getting a big grounded metal box. You want something solid to bolt the transformer to. It's also advantageous to have something that won't melt/catch fire like plastic will.
I'm not sure what's available in your area, but around here you can get one at the local Radioshack, so I don't think it should be too hard to find.
I remade it, how is this?
[img_thumb]http://dl.dropbox.com/u/64443729/HPIM0585.JPG[/img_thumb]
Top is input, bottom output.
No, i won't leave it like this. Just interested to know if i did the wiring right.
Get an icecream plastic container. It has a lid and thicker plastic, so if you seal it off with hot glue it's a lot safer.
[QUOTE=DrLuke;35083553]Get an icecream plastic container. It has a lid and thicker plastic, so if you seal it off with hot glue it's a lot safer.[/QUOTE]
I'm planning to make a custom box, hot glue the parts in place and use some electrical tape to cover the connections.
Anyways, I'm bidding on a HeNe Lasertube! Only 19 hours left, and noone else is bidding so far.
It comes without a PSU though, so I'll have to make my own 2 kV switchmode PSU.
Aww yeah, got my transmitter working more or less:
[video=http://www.youtube.com/watch?v=odGYajIxCG4]http://www.youtube.com/watch?v=odGYajIxCG4[/video]
[img_thumb]https://sites.google.com/site/lonewolfscircuits/sitefiles/TeleTalk2_ExtOverview.JPG[/img_thumb]
[img_thumb]https://sites.google.com/site/lonewolfscircuits/sitefiles/TeleTalk2_IndicatorSide.JPG[/img_thumb]
[img_thumb]https://sites.google.com/site/lonewolfscircuits/sitefiles/TeleTalk2_Inputs.JPG[/img_thumb]
[img_thumb]https://sites.google.com/site/lonewolfscircuits/sitefiles/TeleTalk2_Int2.JPG[/img_thumb]
[img_thumb]https://sites.google.com/site/lonewolfscircuits/sitefiles/TeleTalk2_Int.JPG[/img_thumb]
Bugs to go, and I need a couple new variable caps(The things are really temperamental)
[QUOTE=DrLuke;35083699]Anyways, I'm bidding on a HeNe Lasertube! Only 19 hours left, and noone else is bidding so far.
It comes without a PSU though, so I'll have to make my own 2 kV switchmode PSU.[/QUOTE]
What kind of current is required?
Hi guys, my Arduino Uno is going to arrive soon and I came across two problems regarding LED matrices.
First one :[url]http://arduino.cc/en/Tutorial/RowColumnScanning[/url] in this tutorial it says that you can make a matrix yourself using the provided schematic, but I see no mention of resistors in the schematic.
How would I go about calculating the required resistance?
Second one :[url]http://ruggedcircuits.com/html/ancp01.html#Method10[/url] On this site it shows that if you use 10 or more LEDs it exceeds the microcontroller current limit and destroys the arduino, but how come that people are able to controll people are able to use LED matrices consisting of 64 or more LEDs?
Thanks for your help.
[QUOTE=Levakama;35090646]Hi guys, my Arduino Uno is going to arrive soon and I came across two problems regarding LED matrices.
First one :[url]http://arduino.cc/en/Tutorial/RowColumnScanning[/url] in this tutorial it says that you can make a matrix yourself using the provided schematic, but I see no mention of resistors in the schematic.
How would I go about calculating the required resistance?
Second one :[url]http://ruggedcircuits.com/html/ancp01.html#Method10[/url] On this site it shows that if you use 10 or more LEDs it exceeds the microcontroller current limit and destroys the arduino, but how come that people are able to controll people are able to use LED matrices consisting of 64 or more LEDs?
Thanks for your help.[/QUOTE]
Not all the LEDs are on at the same time and they are usually using transistors to drive the matrix.
Only one row will light up at a time, so you calculate the individual LED resistance you need and put one on every column.
[B]im trying to make 12x4 LED board with arduino duemilanova. i dont think it have got enough pins for it, and arduino can power up all this LEDs on the same time. can you guys please help?
this image shows how it will work[/B]
[IMG]http://itseecan.com/IMG_3615.gif[/IMG]
You basically want an array like this: [url]http://arduino.cc/en/Tutorial/RowColumnScanning[/url]
And then drive it with transistors.
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