Big Theremax Problem

Social life ???????

Theremin builders arent allowed to have a social life!!!!

Fred.

;-)

I would take a new LM339N and bend pins 1,2,13,14 slightly away and put only pins 3 to 12 into the correct places of the socket (are you really sure that you didn't put the IC in the false way round before?)

If there is no total V+ voltage drop now, check the voltages at the connected pins as follows and let us know about the results.

pin 3: +8V
pin 4 to 7: all around +4V
pin 8: +0.5V
pin 9: 0V
pin 10: +8V
pin 11: +4V
pin 12 : 0V

If you see the total V+ voltage drop though, even with all 4 outputs "in the air" (they are open collector, so there is no risk), check R1 if it is still 100 ohms or if it is already defective after the previous "accidents".

hi,

R1 is fine. i checked it.

The IC is putted in the right way. I´m sure!

as soon as i put the pin 3 (Vcc) in the socket the V drops.  Without the IC I get the voltages you posted Thierry.

ONLY at pin 8 i get 4V....maybe this is it?!

So i´ll have a closer look at components connected to pin 8

f**k f**k f**k f**k f**k

forget all...

i have the mistake....

argh i hate myself...

i´ll write later...

first i have to fix it

Nu? We are waiting... ;-)

LOL!!

I've lost track of how many times I've said and done exactly the same thing.

Bashing my head against a wall for way too many hours only to find a simple, easily corrected problem.

Don't feel bad. You're not alone.

Looks like he's gone off for a "social life" again!

Bah!

Bet he had the bloody IC in the wrong way 'round all the time, and is now trying to think of some clever way to get the egg off his face! - thats probably all that needs "fixing" LOL! (could have built a whole Theremax in the time since he found the fault..)

Come clean, Boerker! ;-) Weve all been there! As w0ttm says, Dah dah dah dee dah.. YOU ARE NOT ALONE!  ;-)

Joking aside - There is REALLY no need to feel embarrased regardless of how stupid the fault may have ended up being.. Even after years of designing and constructing there are times I miss obvious things and waste hours in "needless" frustration because the noodles in my head didnt communicate with each other.. And there are times when I have ignored advice, not checked something because I was sure I had it right, and hours later found it was the very thing I had been advised to check, but hadnt - because I had been sure that I couldnt have been so stupid as to have got "that" wrong!

Fred.

hey guys,

it seems that some noodles in MY head were willing to communicate for some seconds :D yesterday:

No the IC wasn´t in the wrong way round!!!! There is/was no way to put the IC in the right way...

Here´s the story: :O)

I made the board by myself. For this i took the PCB-layout from the www. This jpg was, in my opinion, showing the original view on the board. So i mirrored it before print to get it then on the board "the right way"....what more can i say....

I feel stupid. BUT: i´m happy because during the time seeking for the mistake i learned a lot about the theremax-layout/schematic and about electronic in general.  Although i´m happy to know that there are people helping in a very patient and friendly way. THANKS!! @fred: i would love to test the suggestions you made (to be cruel to the the board in different ways...burning components...yeah sounds like fun!!) 

I didn´t finished my work yesterday. Only soldered the IC on the other side of the board to get it in the right position...No voltage drop etc...what surprise ^^.

Next step will be to take off Q1-Q12, spin them andn put them in again. Although the other IC has to be "mirrored"...Hoping that i haven´t destroyed too much other components in the "fixing-time".

I´ll keep you informed !

Again: thanks a lot!!

boerker

ok .. Yeah - fixing a problem like that will take longer than building a Theremax from scratch.. Aaarggg! - What really surprises me is that any of the other voltages were what they should have been!

- And this explains why you were reluctant to contact PAiA - LOL ;-) - theres perhaps some sort of Karma at work here.

Anyway, thanks for letting us know, and I hope you get it sorted.. Difficult to know what else is likely to have been blown up - but I would certainly keep an eye an all active components (IC's diodes and transistors) - I would test every diode and transistor when you remove them to fit to the correct side of the board - see http://www.electronics-radio.com/articles/test-methods/meters/multimeter-diode-transistor-test.php for instructions on how to do this.

good luck,

Fred.

Sorry, cant help...   * R O F L * ... and now I'll need fresh pants... ;-)