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Posts posted by logan_dslasher

  1. aw! i missed Ante's second post.. nope! there's no fuse. that's the first thing i looked for.. BTW whats a wall wart? it has a small PCB inside it, something like 2X2 inches or so.. its where the volume switch and control is placed.

    the speaker system has two speakers, just like in the picture i posted. the one with the volume switch and volume control is connected to 220. it's connected to the CPU not via the USB but into a round port..

  2. it uses 220V. i have tried to set its volume to the max but haven't tried touching its inputs.. i'll do that later. i don't think i have a sound card, there's this oscilloscope and freq analyzer i found on the eLab.. and when i transferred the program to my pc an error message flashed.. it said something about the program requiring a sound card.. so i guess i have none..

    if i try measuring the speaker with a multitester (R x 1) what should the reading be? can i do that?

  3. Hi Ante!

    i took it to the shop where i bought it for them to have a look at it.. i found out that its not under warranty because it is only a free accessory (pretty good technique - when buying a computer package, all you have to pay is the CPU and monitor, the rest is FREE; though the price is increased for the CPU and monitor  >:( ) anyway, having them to tell you what is wrong with it even if not actually fixing it will already cost me something.. so i decided, to try (first) to fix it myself..

    i already opened it.. it looks pretty clean.. no burnt parts or whatsoever can be seen.. what could be damaged? is it the speaker? am sorry i can't provide a picture of it. i don't have a digicam or a webcam for a screencapture..  it doesnt have any obvious damage..

    thanks...  8)

  4. when i got home last night, my mother was waiting at the porch. she said that the computer blew up!! i found out that it's only the speaker that got damagd. she said it made a popping sound as soon as she plugged he AVR. she said the saw something sparked..

    it's still under warranty (i think) so i didn't try to open it and see what's wrong.. i have a BT-693 speaker system. does it have a fuse? maybe that was the only part damaged. how could i check what's wrong with it? let's say i perform a "surgery" on it, where should i start looking for the damage? if it has a minor damage, i want to fix it myself..

    i wanted to learn, please help me... thanks..  :)

  5. the problem i encoutered with my inverter was due to the damaged IC.. remember, when i was working on the whistle responder circuit, i used some of the left over parts in making this project.. after i solved the inverter problem, the OR stage malfunctioned.. it's output was always low..

    i have solved the problem.. i used the same technique that revealed that my 4081 was defective, since both the 4071 and 4081 have the same pin config, i replaced my 4071 with a 4081. the 4081 worked properly, therefore, the connection was fine. i replaced my 4071 with a new one. it worked fine..

    why do ICs gets so easily damaged?

    i finished the whole project just in time... i hope my friend will have a good grade.. and i'm pretty confident he would.  8) thanks you guys..

    on the other hand, i learned a lot too.. he said the next project they have to pass is an AM radio receiver..

    tahnks again for the help..

  6. i have spent all day working on the project. at the very last stage of assembling it, i encountered a problem. the inverter input LED doesn't turn ON even if i apply a high to it.. i've traced evferywhere for the fault but found none.. maybe, i'm just too exhausted, so i tried to unwind by playing online games.. i think i'm ok now.. i'll figure out somehow what is wrong..

    just a question, one of the LED is not very bright.. it is connected by a foot-long wire. should i shorten it? how about my question about TTL vs CMOS? can they go together in a single circuit?

    thanks all for all the help..

  7. :)audiou guru is a major doctor in electronics , his skills and the way he can diagnose a circuit by looking at it and exsplain all the functions and technicle details like that makes me envey him, i wish i can do that he is brilliant like others can be . he is an asset to electronics lab , and id love to shake his hand and lern from him he would make a good teacher, in electronics .

    hi Steven!
    who doesn't envy audioguru? you want him to be your teacher? why, i'd like him to adopt me!!  ;D  ;D  ehehehe.. i'll have the papers ready, audioguru ..  :D

  8. I got it finally! its working now!  8)

    at first i wired it like that shown in the "tutorial" using a 4081.. it have varying results...i noticed that the 4081 was hot..  knowing that the pins' layout of a 4081 and a 4071 is the same, i repaced the 4081 with a 4071.. it worked! then i also wired a 4049 just like that again with the "tutorial's" diagram.. again, it worked. all i have to do now is look for another 4081.. i concluded that it is damaged..

    i also had a problem with the BC547B while i was shopping for it.. it's not available (what's new?!) most of the shops don't have and ECG (electronic components guide? ??? -- wild guess) there's this shop in the locality that sells their goods at almost 5 times the prices in most of the shops.. it has an ECG.. i inquired about a 547 but was not available, so i asked what could i replace it with.. she said a 548 is but costs 65 pesos.. i said i'm short and i have to return to get additional money.. (i just needed the info  :P) i found a 548 at another shop for only 10 pesos..

    all i have to do now is mount it on a PCB and placed it on the back of an illustration board and pop the LEDs onto it.. i'll have the schematic drawn to the board with the LEDs placed on its inputs and outputs.. i also placed LEDs on its input.. my friend even requested to have a truth table .. instead on 1's and 0's, we'll place LEDs.. i said that's very impractical and redundant!! it would also cost too much..

    question, what's the difference between a TTL and CMOS? can they go together? what if instead of a 4049 i have a 7404 (i think)..

  9. ah, alright, audioguru.. i'll just leave them there.. i'll just copy the wiring as is.. assuming that i can make the circuit work, how should i connect it to another IC? i syill have to use an OR (4071) and an inverter (4069) how should they be connected.

    in a 4071, does it have the same wiring as that of a 4081? How about for the inverter?

  10. i have located the omega under subset of "letterlike symbols".. MSWord gives a very limited symbols -electronic- you can use..

    you can also use the Equation Editor under "costumize.." in the Tools menu.. look for it there..

    i think the best you could do is find an electronic software that has the ability to create schematics (eg. multiSIM, eagle, eExpressPCB.. etc..)Using them, you can have a wide range of electronic symbols you want to use.. copy paste..

  11. hi guys.. i think i found an answer to my problem.. i was looking for the pin assignemnt of a 4081 and this turned up: http://www.doctronics.co.uk/4081.htm#pins

    i just ha a question: what are the capacitor and transistor for? is it alright if remove them? and how about the unused gates? i thought they are supposed to be connected to something..


  12. thanks for the additional resources steven!

    if i supply the circuit () with 12V, what should be the resistor values? i can't come up with a good schematic on how to wire the three IC's (4081, 4071, 4069)together.. ill try it on my breadboard later.. am still busy with lots of things right now..

    thanks for the help!~!

  13. here's what i did..

    i have a 4081 (quad 2-input AND).. pins 1,2,3 is AND1 456 is AND2 and so on.. pin7 is ground and pin14 is +9V..  I have a LED placed in pins 3&4 ('im really not sure if it should be placed there..) then I use two wires to connect pins 1 and 2 to pin14.. theoretically (my theory) is should have the LED lit. high input to pins 1&2 should produce a high, turning the LED ON, right? bu what happens is the opposite. the LED is OFF if both pins1&2 are connected to pin14' it is ON if only one is connected. what's wrong? please advise...
  14. i thought i got the whole thing figured out!  ??? where would i put the LED? the supply? i am using a 4071 (OR) a 4081 (AND) and a 4069 (inverter).. the output X is = AB + B'

    i have the inverter connected to input 2 of AND. outputs of AND and inverter are the inputs for the OR..

    i got confused.. ??? i suspected that the breadboard im using is defective but i think there is something wrong with my wiring..

  15. have you removed a small rotten part on a banana using a spoon? that's how my index finger looked a while ago.. i was working on an AC/DC converter. i was drilling (using a hand drill) a hole for  the fuse on its chassis when the drill bit suddenly got stuck and the aluminum box spun with the bit.. it happened in a flash! then i realized there was blood on the floor.. then, i flet a tingling sensation on my left index.. only then that i realized that a "chunk of my flesh got scraped.. my lil' bro applied first aid..

    There are dangers in electronics.. i just want to remind you all to be safe in evrything you do!  the planet needs us!!  ;D eheheh..
    BE SAFE!!  ;)

  16. i used to be in the same situation you are in.. i've done "extensive"  :P research what to do for my project.. i have kept a list of the sites i 've visited.. i hope they would be useful.. actually, you are in a very good site.. try the projects section of eLab.. i'm usre you'll find something there..

    welcome to the eLab anu!!  ;D


  17. http://www.electronics-lab.com/forum/index.php?topic=627.0

    Nice Project! is that limited for a 4011 only and some other 14-pin ICs? how about those with 16 pins? i noticed the stickers pasted on its chassis.. "4011, 4093 and 4001" are those the only ICs that can be tested by that project? anyway, i don't plan to build one, i'm just curious..

  18. thanks.. i have already asked my friend to purchase a CD4071 (quad 2-input OR gate) and a CD4081 (quad 2-input AND gate) he'll be at my place tomorrow.. i am planning to have it assembled in an illustration board.. i have a schematic circuit drawn in the board, drill holes for the LEDs and the IC's and at the other side, have the wires.. what is better to use, a switch or an alligator clip? he said that the power supply would be that from an AC/Dc converter.. probably 12V, right?

  19. Hi dave!

    thanks a lot for your idea but it is really important that the circuit contains real gates..

    the next time, attach files in jpg, or png format.. if your attachment is in bmp format, simply use "save as..." in the file menu and below the file name, you'll see a dropdown menu what format you want it to be saved. choose JPEG..

    tahnks again for the idea..
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