minya

thank you guys for helping myself in this noob problems ... so i took my last 7912 which i had laying here without any usage before and switched the i/o as you told me johnybee (as in the drawing but i/o switched) the consequences are not far away from the issues before when measuring DC: 0 V vs -12v -> -17,8v 0´V vs +12v -> +12v -12v vs +12v -> 30v measuring AC: -12v Vs 0v -> 0V +12 vs 0v -> 26v +12v vs -12v -> 65V shouldn't all AC measuremens be 0V?

hi stryde_one, it gave me 17v after i changed the pinning of i/o in 7912 at the first time "when i measure 12- vs ground there are about5v more, when i change the pinning of the 7912 i/o there is 24v" after i read the threats i thought i crashed the 7912 when i changed the pinning, because doc told me, that he got also 17v after he wired the 7912 wrong. now i checked the pinning of the 7912 before carefully and did not rewire it ... i have following pinnings at 7912 ground to ground, input to 12v- output (- of the small elko) output through the small cap to - of the 4700uF elko bugfight told: "is the decoupling electrolytic cap backward on the 7912 input? the + side should go to gnd (which may be confusing) and the - side to the i 7912 input..." ps: i deleted the first pics, because of thir size, i'm not a fan of big pictures, but i thought you wouldn't see anything if i make them smaller ... :) i'll try to mak them more shape and smaller next time thanks, markus

it is incredible! i rebuilt he hole circuit working excact and not so dirty as in the first one ... i changed the 78xx and 79xx, 10 and 100 caps, the diodes and i've got exactly the same problem! the 12+ V vs ground is ok, bt the 12v- vs ground gives me about 24v i gues the 7912 vom reichel are not working ... i don't know what else can be the problem. i used 3 different of them but nothing changed. i took vacation for today, that i can do that and the parts for building the 2 transformer version have not jet arrived :'(

hey guys, thank you very much for your replies, that could be the issue i was looking for ... so can you tell me if the input or the ouput goes to the 12v- line? so that i wan't solder it wrong the next time :D markus

i checked the circuit a few times but i have no idea where the problem could be. so i'll buy a 2x15v transformer today and build the circuit 1 with 2 tranform ::)

i also thought about an 79 pin issue, but also changing input and output does not change much, but the above mentioned volt change at 12v-, the ground pin must be correct! i made some photos and tried to mark where the circuit is, but i'm not sure if you can recognize all details. it looks real bad because i just changed the diodes on the back quickly and the i/o pnning of 79xx to see if they cause the error the solderings in the middle rectangle is the 9v transformator

hey thanks for your fast reply, the - of the small elko behind the 7912 is connected to the input of the 7912, and the output of 7912 to the ceramic 100nf and also the - of the big 4700uF elko i guess that should be ok

hello, as described in my fm-threat i built the psu unit today. but i thought it wouldn't be good to put this question into it i build scheme 2 of +-12v exactly as told on the page (with 2Diodes and 1x15V transformer), now i've got the half part working :) when i measure 12v+ vs ground the power is ok at 12v, when i measure 12- vs ground there are about5v more, when i change the pinning of the 7912 i/o there is 24v ... i don't understand this, exspecially because the 12+v is exactly the right amount. but now there is something else which confused me completely, when i measure at ac scale, i don't get zero. Measuring - vs ground is ok, and +vs- is also ok, so it seems as a ac circuit exists át 12v+ ... i don't understand that, i have changed the diodes and the 7912, checked the circuit nearly 10 times and i don't have an idea what can cause that. thanks for your help, markus

wahhhh those reichelts sent me the wrong caps so i have to buy nother one tomorrow, and i'm still thinking about the two transformer solution ... let's have a look what the conrad guys will offer! is there any modification needed with the 9V transformator? have i got to build the same recruit thing as on the 12v one or can i use it directly? in the ics of thorsten saw there were three 79xx / 78xx ... thanks

hey strype one thanks again for your reply ... yes i did my homework and read a lot. please don't worry about ordering some caps, and i don't believe that your post was senseless, i read it very interested and talked tonight to an electrician, who told me that solution 1 would be the best. but i'll try it with the single transformer and tell you if it works. but nevertheless i'm verry glad aboutyour answer and am very sorry about making you the work! peace, markus

hey loona, thanks for your reply! i also read a few things and the 78xx and 79xx pinning should be clear now, thanks again! i found a cheap tranformer at reichelt and bought this, it's just a single one, but as i understood the threats i read it shoukld also work fine with scheme 2 ... i bought WIPPE 1832.3312 Wippschalter, 2-polig AUS, 20(4)A/250 1 1,95 Euro FLINK 0,63A Feinsicherung 5x20mm, flink 0,63A 4 1,16 Euro SB 140 SCHOTTKY-DIODE 1A/40V 4 0,53 Euro FLINK 0,5A Feinsicherung 5x20mm, flink 0,5A 2 0,58 Euro TEKO 364 ABS-Kunststoffgehäuse 311x170x87mm 1 15,50 Euro MKS-2-5 100N WIMA Folienkondensator, Rm 5mm, 100nF 6 0,74 Euro RAD 10/35 Elektrolytkondensator, 5x11mm, RM 2,0 10 0,41 Euro EI 48/16,8 115 Trafo 10VA, 15V, 666mA 1 4,10 Euro LEITPASTE 10GR Wärmeleitpaste, Metalloxydpulver, 10g 1 1,70 Euro BSN 4.700/40 Snap-in Becher-Elko, 25x40mm, 4.700F/ 2 5,40 Euro PL 112000 Sicherungshalter, 5x20mm, max. 6,3A-2 4 0,49 Euro SM 10/16RAD Subminiatur-Elko, radial, 10µF/16Volt 4 0,29 Euro V CK960/20 Aufsteckkühlkörper für Gehäuse TO-220 2 3,40 Euro KES 1 Kaltgeräte-Einbaustecker, waagerecht 1 0,30 Euro EI 42/14,8 109 Trafo 5VA, 9V, 556mA 1 3,30 Euro FLINK 0,8A Feinsicherung 5x20mm, flink 0,8A 2 0,58 Euro i hope the 15v 666mA and 9v 556ma transformer is enough for this project. i already thought about the fuses, they are obviously too little for using. For scheme 2 it is told that the double caps size of the elkos should be used, i took 4.700F/40v hope thats ok, and i hope the diodes will also work i haven't found a good and safety looking +- transformer, that's why i decided to try it with this markus

hi strydeone, thanks for your fast reply! yes i think it heps a lot and i'll try to buid the same one if you think that works fine for the fm. another question, what is exactly meant with the double size of caps? aren't they just 100n and 10u ones? the ground conections in the middle are also connected aren't they? i already ave the 78xx and 79xx here, i can't build them in the circuit on the wrond direction? and one last thing ... is the thing on the left side a diode and which one shall i use? i'm sry but i'm not really experienced in electronical circuit but nevertheless i want to build it save and working fine. cnan i also use the mk528 with circuit scheme one ... in the wiki they tell something about 15+-v and this one is 13,6v is there any mdification needed with the 4,2v output or can i use that directly? thanks for your patience :D markus

@foona: hey thank you very much! i love to hearing that ... i already downloaded the scheffer software to but i did not jet found an option to make white panels there, just black ones. but at the website they also offer white one ... i'll phone them tomrrow and ask if that would be possible @strydeone: yesterday night i watched the psu options which were provided at the wiki and i'm not sure if i shall take one of these, the c64 one, a already build +-12v one ... or however. Do you know if they all work fine or if there are some problems with the fm and one of these psu systems? i thought about method 3 "3. Then there are two excamples of how to connect two identical 12v power adaptors. It is very important to use two identical ones! Same brand, same rating, best bought in the same shop the same day! You get these in regulated and unregulated versions." might i do this with this transformator http://www.reichelt.de/?;ACTION=3;LA=4;GROUP=C525;GROUPID=3316;ARTICLE=27370;START=0;SORT=artnr;OFFSET=16;SID=27d-jEZawQARsAAHTfbLcdc8d159c31b1d24dda8b52285bcd8c75 and scheme 3 for the 12+-v psu and which one can i use for the 5v voltage? ??? thank's markus

hellau, all modules are ready soldered, dinx doutx, core and ymf module are done. Today i wanted to buy an transformer, but i read in the forum that it is possible to use the c64 one. i have one laing around and so i decided to use this. can anyvbody tell me if i need some accomodations or can i use it directly? has somebody maybe a scheme about the c64 transformer pinning? thanks and regards, markus

Hello guys, i'm very proud having my first DIY Synth just started! I decided to build a SID Synth with as much SID's as possible and also a YMF262 FM Synth. When i tried to desolder the yac chips i was overtly too rough and broke some pins. But fortunatelly i had found another soundcard on ebay, bought it and now the YMF scheme is ready soldered. I thought about doing the same 19" version as shown on the ucapps site, but i came to the conclusion, that my 19" Cabinet is already full enough and a desktop version would also be very beautiful. So i just drafted an idea i had last night. I want to build the FM Synth in a white coloured frontpanel and some wooden parts on the side.... here is a small draft of my idea... these days i'll take my order from the tax office and build the rest of the schmes which were needed ps: sry for bad english skills :D ppps: the draft is build with the original version jpgs of TK and just arranged in another way peace, markus