Genenral Questions

Started by Daniel, September 18, 2004, 07:57:58 PM

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Daniel

Hi there,
srry for asking this here as its not linked to the beginner project but as i thought this is like the beginner's place it would be ok. (if not tell me and i'll ask the future ones on the other board ;p)
I'm trying to build a Boss SD-1 or is it  DS-1? hmm well.. one of them...
i make all the pedals on a Protoboard before going to perfboard.
I made it on the PB, revised like 2, 3 times the scheme (so i think/hope its ok) but still i only get noise.
1st: how can i test a IC? it uses 2 4558 which i'm not really sure they ok.
btw, i can use only one circuit from the IC, right?
2nd: the jack connection. As i said in another topic (about the boost project) i'm using a differnt kind of Jack. It has like 6 places to solder (3 of them that works when the jack is not inserted). How do i know what is what?
btw... one of "places" in the jack goes to the ground and the other one to input/output. right?! =D
Thx alot ;p
ps: srry for the bad english =\

Lonestarjohnny

First off, do you have a multi meter for testing voltages ? then you need to do a google search on the type of 4558 like Texas Instrument's and download a data sheet, it'll tell you the pinout,
sound's like you have a Stereo jack, you need to go over to the Newbie side and study the way to wire a stereo jack, it's there, just search, you'll find it there and in the archive's,
once you have this down, post the voltage's your getting at the pin's of your IC here, someone will help you trouble shoot it
Johnny

Boofhead

Quote1st: how can i test a IC? it uses 2 4558 which i'm not really sure they ok.

A large proportion of problems are wiring errors, shorts, poor soldering, electrolytic caps around the wrong way.  It is often easier to check the opamp in the circuit - since a test circuit isn't much different to the real circuit.  Checking the opamp in circuit can help find other problems/errors - it's all a process of elimination.  Whatever approach you take you will really need a multimeter. The place to start is to check there is power getting to the circuit and tothe opamp power pins.  Next check the DC voltage at the opamp output and the opamp inputs:  for a single supply circuit all should be at half the supply voltage, for a dual rail circuit all should be about 0V.   This only applies to opamps which pass the audio signal - in other circuit positions like oscillators (eg. LFO's) yu have to check a different way.




Quote. It has like 6 places to solder

I can only guess this is a black plastic type of connector.  On these you will see one side of contact which spring-up when you insert the jack - these three connections are the ones which connect to the jack.  The others are switch contacts which connect to the jack connections when the plug is removed (some types connection connect when the jack is inserted).  You can see the connections on these - the gound is closest to the mounting nut.

Regardless of the connector type the easiest way to sort out the connector pins is to insert jack and check with the multimeter buzzer.  Since many connectors have stereo type connections it's more accurate to use a stereo jack but you should be able to work most of it out with a mono jack.