technobreath

UPDATE: I finally managed to step onto the scale for the first time in months :P hehe. The official numbers 6 months ago is 128 kg The official number yesterday is 121 kg Improvement, wich I suspect is the results from the last two months only, but I have no proof for this since I haven't actually paid attention to the scale :) What kind of pictures u want? :D Dirty or tender? :D tbreath

Many thanks for your swift service on this bulk alex! Mine recieved in Norway, all accounted for - all slipped through the customs without any extra costs - nice :)

photoshop is nice... altering the reality is for boys hehe - this poll is if I'm gonna be a man and skip te photoshop tricks and get real.. :D

ah ok, I have a mb6582, and I think I'm gonna use that style of panel. So count me out again then ;) thanks for info.

Though the sound style wasn't my taste, this I must say was a pretty nice piece of work. Very cool, and I'm sure the kids dig it!! :D

For sale? I'll take one off your hands :) How much you want for it?

The recipe is veery simple. You eat less than you burn off. And the challenge is in finding a good way of doing that... I have a plan for how to do it myself, but there is no kg loss without sacrificing something :) So I eat way too much snacks wich I don't need, and I also eat dinner all day, so all that need to stop, but all in time. No shock therapy. I've tried that before with only temporary luck :). I've always wanted to try some martial arts training, and was invited by a friend, but didn't find the time to commit to it, so it never got anywhere. I also walk 40mins two times a week - wich is gonna be more often as I get in better shape ;)

too slow there :( heheh

:D Yes, and I'm sure a picture of your big mouth wouldn't fit either :D hehe Photos it is... Just need some time to set up the photostudio and we're on :D

Photos? Are you sure you guys can handle it? :D

Since it seems that I can't decide myself, I could need some help from you guys. You decide! :)

I can feel this is passionatly igniting my anger! This is so uncool! Did they f.ing think that it would go unnoticed? Or what? You guys TK and wilba are gonna do something, right...?

I would also be willing to sell some of mine, since my order was pretty big. I planned to use it for future projects, but if someone need them NOW and missed the bulk order I would absolutly be willing to help out - there will always be another bulk order :).

Good luck. Maybe u could come back and show us the results of ur work, would be fun to see what u get out of ur project.

Sorry, cant find a way to edit post on my phone, But another thing i thought about is that i have some huge mosfets lying in box here. They were intended for driving big dc motors on a precut saw. The technician on the site left them behind in the factory they built it along with other components. They are rated about 100amp if i remember correctly. It would be cool to use them instead of the bipolars. A wee bit overkill yes. But since i have them... i havent studied mosfets very much, so if anyone has an idea on if mosfets can be used please speak up... I will anyway make the design for bipolars, but i could use them in my supply and make the necesary changes for my own psu if they can be used.

Hi. It might be that the pic is lowres or i cant see it properly on my shitty htc, but i cant seem to understand the meaning of the transistor that passes over the vreg. I mean, i see its the pass transistor, but how does it actually work? I thought its base was supposed to connect after the vreg and not before... again i am no expert though... hehe. Ur schem seems interesting though, a bit more advanced than my basic idea... could u explain what the intention with the design is? Good work. It would be cool if we could come up with a fairly simple but good design that everyone can use. When i started projecting the psu i soon discovered that it was far more to designing a good psu suited for this delicate application than i first thought. I really enjoy learning about it. I have struggled for many years to learn about psu, logics and electronics in general and really understand it. I never went to any school about this, so everything i know i learnt from the internet, my dad who used to design industrial robots for a living and from the good people in here. Especially smash and nils. Im working on the schem tonight, and ill post it later on.

This is a good idea, and is very similar to my design. But current limiting / crowbar and fuse is even more important with pass transistor. I have looked at tip31c as the limit transistor. Its 10A. Havent done the math yet, so ill have to do some calcus to see what the actual needs are.

Hi As it turned out i had too little time to work on the schem this saturday, so i will do some work tonight and monday evening. I recon i will have a schem ready then for you to see. I have thought of a couple of new things to add, ie led indicators for normal op and protection. Ill see if theres a simple way to do it. Afterwards i would need some serious evaluation of the schem from people who knows this stuff, so if anyone feel like they can verify the design and suggest changes, speak up.

No, this isnt the design I posted - I thought I had posted it in the forum too, but I might have forgot :) But I'll make a new version of the schems tonight and post it later on since new information has surfaced since I made that design. I will post as soon as I have made the new version, and you guys can tell me what you think. My design has no -12v rail yet. I haven't incorporated it yet because I have to keep my head straight when doing the design... I figured that if I do the positive side first, the -12v rail would be pretty easy to do afterwards. Many thanks goes out to nILS and SmashTV for helping me out being my "tutors" in designing the psu :) - you guys really pointed me in the right direction :D. The one thing that sets me back now are xformers. I have none and I'm struggling a bit to deciding what to use. I think I will decide on a design tonight and order in the part so I can finally start making a real prototype, and stress-test it a bit to see if it actually works. About crowbars: There is a thing with all simple current limiting circuits - as you mentioned above in some post - they are vulnerable to false triggering on startup. I think the main reason to this is large capacitors on the power rails. They charge up really quick, and when they demand some power at startup to get fully charged that can actually trigger the crowbar and the fuse will blow. I guess if the fuse doesn't blow you will get a hickup from the psu turning on / off / on / off and so on. The solution might be to use not too big caps in the psu and also set the crowbar's zener to a reasonable voltage so that it doesn't trigger the scr or thyristor too soon. The diodes for latchup is interesting part I haven't looked into yet... I will read some more :). I'll be back later on with my new version :) See you.

Hi. Did u see the design i posted in the chat? I assume u dont talk about the rectifier diods... There is no other diods in the designs appart from the zener diode. The fourth one that looks like a double diod is a SCR. it is the shorting component in the crowbar. The zenerdiode is a 6.5v and it works this way; When the voltage reaches 6.5 volt the scr will turn and thus opens connection to ground and shorts the psu long enough for fuse to blow. But the crowbar depends on current limiting, such as a fuse or a fuse in combination with current limit transistor. Even if a crowbar is defined as a overvoltage protection, voltage and current has its relationship...

-9v? I didn't think you needed -9V. Haven't looked too much into the specs of the c64 psu, so I can't do more than asumptions... Are you building a c64 psu clone or are you using the brick itself and want to know what pins goes where? In that case I can't help you very much. In case you build a clone - don't :P. If I'm not totally off here, the correct values for 8580s should be +5V, +9V and ground. Where to connect this on the baseboard is well documented in the wiki. Haha, reminds me of a former collegue of me. He always said "it sucks several meters of infected cock!" :) hehe. I might have been a bit quick when dragging the vregs into this. I assume when I think about it (have to check the datasheet) that the currentlimiting in the vreg is pretty good. But when you need to draw more current than the vreg can deliver you need to use a pass transistor. It is controlled by the vreg and depending on how "big" the transistor is, you can draw muuuch more current from it than from a 78xx 79xx regulator itself. To protect all this you use another high power rated (don't remember all the details just now) transistor and a resistor in series with the load to control the base of the protection transistor. Collector of this is connected to the base of the pass transistor, and the emitter to ground. When current draw through the sense resistor raise above a set point (depends on the amps you wanna be able to draw out of it and the value of the resistor) and thus the base voltage (on protection transistor) reaching 0.7 volt (if i remember) it activates and short the voltage to ground. So the protection transistor need to be able to withstand a lot of power - much more than the pass transistor - to withstand this shorting. And when the transistor is shorted, the fuse will blow and everything turns off, and all you have to do is to change the fuse if you're not too unlucky. Look at it this way. The transistor is a superquick switch that when it activates it "turns off" the voltage at the base of the pass transistor by shorting it directly to ground (the current will always flow the easiest way to ground). Making this short in the psu makes the fuse blow. So in short - it shorts out the powersupply in order to protect it :) only difference is that you short it on purpose through a component that won't brake. There are another option (crowbar circuit) based on a SCR (or thyristor or so if I remember correctly) and zenerdiode that function about the same way - only that the short is activated by a voltage threshold instead of current sensing. This voltage is set by a zener diode (and a resistor) and the zener diode should be set a tad higher voltage than what's actually on the rail - thus preventing false shutdowns. I don't remember the exact details without looking in my books, but it is the idea at least... So if you protect it with both a crowbar circuit and a fine tuned current limiting circuit and a fuse you will be very secure. I'm not really sure you need both circuits, would probably be enough with one of them and a fuse. At least this is the way I'm told it work :) Wikipedia has some good articles on transistor based current limiting.

That's what I said. Typo from me: I said fullbrigde - I meant of course full-wave :). Yes, the vregs will shut down when they get hot. But this is as you get into here, not good enough. If ideal conditions in mains would always be ideal, and not fluctuate, it would from the formula you mention (yes it is pretty close to correct at least at 5-15 volts) be more than enough with a 12V transformer - you wouldn't need a 15V transformer. Worst case scenarios should always be taken into account when designing psu, so you should be safe with a sec. 15vac transformer yes. You could always build a capacitor bank also to feed the psu when the mains drop too much... just a thought - don't know if it actually works :). The worst case scenario would be something like a short in the synth's powerrails. This could lead to failure in the psu, and would lead to failure for sure in the synth itself. The synth would draw too much current, and the vregs would shut down eventually because of heat. Another scenario would be that for some reason the vregs would short, and then what happens? no regulation and unlimited power until something else brakes in the psu, and by then the synth is broken. For this you should have a fuse - yes - but also a (very)high power transistor and a sense resistor that can take the watts needed to cut off the voltage at the input of the vregs or at the input of a pass transistor if used and sink it to ground long enough for the fuse to blow. This isn't exactly very costly, and it adds very few components to the supply, and it makes it a LOT safer for both the supply and the synth, so why not just do it? :o I work with CCTV systems, and have set up a lot of them myself. When there is a short in the load or the cable to the load - the powersupply I use will blow the fuse. Correct the error in the load - replace fuse - and you're up and running again. This will not be the case where the psu hasn't got the proper protection. Instead you get to spend time searching and correcting the fault in the supply. If you want a powersupply as safe as possible and one that lasts over time, you should also build it with that in mind.. it won't run of mind-power :). Also, be sure to serve the synth with sufficient amounts of amps... All I said, the psu design isn't secure enough for use with such precious equipment. And also the C64 brick isn't secure enough either as I stated. This is based on second hand experience - I haven't seen one fail myself yet, but if it does - God be with the synth... Also if there isn't enough current served from the psu, you could get in trouble with backlit LCD if you are a bit on the heavy side of brightness... If there isn't enough current, the voltage regulator will not work and it will drop the voltage and all will be working very bad... I only say that when designing PSU one should do it based on the maths and not based on asumptions that might not be correct at all.. It is not very hard to do the math, and therefore you should do the math :D I can't remember if I said this, but the reason why I say that it the voltage from the rectifier should be as high as you need (with WCS taken into account), is that higher voltage means higher temperature... So there is nothing to loose and all to gain by doing it properly when first doing it. So, as I said about PSU design - getting the right voltage out of it really just takes you half-way there... in my opinion.. :)