Staigen

Whats? Hehe :) :D ;D! //Staigen

Good luck, Mukhalled ;D And keep the good thing going ;D Keep on experimenting ;D You learn a lot by your own mistakes ;D And also by the thing that works ;D And you have fun at the same time ;D BTW, the amp you and Audioguru buildt, is it something i have missed? //Staigen

Hi there Works here, just click on the link, but i dont think it is Audiogurus video! Where are your video, Audioguru, didn't you promise one, or, as usual, do i remember wrong :)? //Staigen

Hi there again Mukhalled :), nice to see you Well, a kit would not be that complicated, i belive. Try it, if you can find one :)! I completed one a few years ago, as i say, and it was not that hard to do. //Staigen

No, i'm not gonna build one, it was Mukhalled who was asking for simple circuit... //Staigen

I assembled a kit a few year ago, for a friend, i belive he ordered it from germany, a realtime analyser, a simple one, it was based on a few IC:s and, if i remember right, 100 Leds, or was it 200. It was suddenly not an easy project, with surface mount components and all! And that was only the analyser. //Staigen

Hi Mukhalled Are you joking :)? //Staigen

Hi there again Um...Me123, sorry i didn't had time to reply your questions until now :( No, as Audioguru say, the transformer itself output AC, it is then rectified in the rectifier bridge and smoothed with the 2200 microfarad electrolytic condenser! The output from this PSU is DC. The AC from the transformer is rectified by the rectifier bridge and becomes DC after that.

Hi Um...Me123 Yes, sure you can, its only the secondary that have to be 28 Volts! Wich supply are you talking about, the supply with the L200 dont have a 28V transformer, if i remember right?

Hi there Kensoft, velcome to the forum :) I belive the chips are 4164 dynamic ram memorys, if i remember right it is 64 Kbit chips, but i'm not shure, they are rather old today :(! //Staigen

Hi again Disconnect the wires temporarily and connect a trimpot for testing, to see if this cure the problem, or at least make a change. If it work then, use screened wires, and see if that will work! //Staigen

Hi there again Kain Is the IC properly bypassed? With a ceramic 0.1 uF condenser as near as possible to the IC.This is surely a strange behaviour! //Staigen

Hi there Um...Me123, welcome to this board :) You shold consider buying a digital VOM( or what the name for it is), a Volt/current/ohm-meter too The LM317 Power Suply in the Projects section of this site is a good start for a PSU for a beginner! :) A link is here: http://www.electronics-lab.com/projects/power/010/index.html Also check the conversation about this project, a link is provided in that section //Staigen

Yes, in similar constructions i have seen, the rectifier is only halfwave, with only two diodes, the anode of one diode connected to the common negative and the catode of the other diode connected to the powersupply's positive terminal! //Staigen

Hi there again Kain :) I'm not shure what happens, when you connect the thyristor the way you did, but it's not correct, thats for sure! BTW, isn't the resistors in the gates( R18 and R19) a little bit large(100K), maybe you should try smaller ones here(10K or so). I know the thyristors are highsensitive, but....? //Staigen

Hi there

Hi there Kain :) So you dont see the error in the shematic? The thyristors Q1 and Q2 are connected to AC1, but the "ground"(the negative connection of C2) of IC1 is not! The gates of Q1 and Q2 shall have their steering pulses related to their catodes! The output of IC1 is related to the "ground", and not to the catodes of the tyristors, i belive that is the error! A simple solution would be to connect the "ground"(the negative connection of C2) to AC1( a short over the left diode in the rectifier bridge) //Staigen

Hello, im back! Well, Audioguru explained it wery good! Thanks Adioguru, then i dont have to write so much, i'm not so good in the english language! //Staigen

Hi there again Autir :) Oops, this was much, shall we take the fuses first. The transformer is rated at 9.6 VA at the output, but the efficiency is only about 75 to 80 %, so the current is going to be at least 55 mA on the input, but with a fuse that are rated at 55 mA it surely is going to blow bcause of the inrush current, also, a fuse that are rated for 55 mA is not a standard value, nearest is 63 mA, but this value is also a little bit on the low side, next standard value is 80 mA, and that i suggested, hopefully this will not blow, but dont be too sure about that, the next standard value is 100 mA, if that one will blow there is an error somewere. Then we have the fuse on the secondary side, not much to say about that, the transformer is rated for 800 mA so the fuse will also be 800 mA! Then the capacitors in parallell with the rectifier diodes, it was something about dynamic high frequency ground, it is a site out on the internet somewere, i dont remember where, explaining this. All i know is that they should be there, this was known already in the 1920:ies, i have seen it in old receivers from that era. The value i think is empirically found. Ok, if there is no resistors connected to the output. Then the diodes over the regulators. I mean a diode connected with the anode to the output and the catode connected to the input of the regulators. If you have a capacitor connected to the output and the fuse blow or you shut down the PSU, and a load connected to another output, the rectifier tank capacitor is exhausted very fast, then you have the voltages over the regulator reversed. Then the electrolytics at the output, they reduce the dynamic output resistance(impedance). Then it was the ideal transformer for this PSU, i think i take that in a later reply, i have to rush, the store is shutting down! //Staigen

Hi there Kain Shame of you, sending up a shematic with such a serious error in it, and asking us to analyze it, and why it is not working as expected :( :)! Shame shame shame Back to the CAD software!

Hehe, i am a pensioneer

Hi there Autir Well, i dont belive she is a beauty, but if it is your first circuit it will do :) But you will have to do a few changes first >:(! But first to the questions about fuses. First fuse should be in the mains section of the transformer, its a 9.6 VA rated one, about 80 or 100 mAT(slowblow) will do here, than a second fuse in the secondary, between the transformer and the rectifier, 800 mAT(also slowblow) is the choice here. Thats the fuses. Then to the changes, first, the rectifier diodes should be parallelled with capacitors(4.7 to 10 nF will do here), next, remove the resistors in the outputs from the IC:s, next, a diode, connected backwards over the regulators will save them, if the input voltage to the regulators is lower than the output from them, 1N4001 will do fine here, next, a 10 uF ellyt parallelled with the 100 nF condensors on the outputs from the regulators should be fine too. Done this, this will be a nice little PSU, but it will surely eat fuses for you, every time you overload the transformer, this transformer is too small for this circuit. Also the output from the rectifier is not enough to the 7812 regulator, when loaded! Dont forget to heatsink the regulators properly! Good luck! //Staigen

Hi there Kain This will surely not work, take a close look at the PSU:s rectifier! The output to the Zenerdiode is taken from the input to the rectifier bridge and the input to the bridge is connected to its output. Also, small, lowpower PSU:s for things like this usally not have rectifier bridge. As you see, the catodes of Q1 and Q2 is related to AC1, then i belive the "ground" of D2 and IC1 also should be connected to AC1! If you then connect the output of the bridge to VCC and move the connection of the 680 nF condenser to both inputs of the rectifier i belive that it works. Usally you also have a little resistor in series with the 680 nF condenser, in the range 100 to 300 ohms, to reduce inrush current, usally 1 to 2 wattage. Hope this help. //Staigen

Hi Ante, i had Grisoft AVG, but it did not react! I also had an old version of Norton antivirus, not updated in several years! Does anybody have a copy of "Lost and found" maybee? //Staigen