RE: FBSSTC-NEED HELP

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Tom Luttrell PWRCOM" <tom-at-pwrcom-dot-com.au> 

Things to check if you have no voltage out of the 7812:

1) Is it connected the correctly? http://www.national-dot-com/ds/LM/LM340.pdf
2) The heatsink tab is connected to the middle pin (COM) for positive 
regulators, make sure it is not shorting on either the input or output rails.
3) Is the input voltage at least 15V?
4) Add a 0.22µF cap across the i/p and  COM (7812s can oscillate and lock up)
5) Ensure  the max current drawn is less than 1A.

Tom L.


 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Wednesday, 24 March 2004 12:02
 > To: tesla-at-pupman-dot-com
 > Subject: Re: FBSSTC-NEED HELP
 >
 > Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz>
 >
 > On 23 Mar 2004, at 6:50, Tesla list wrote:
 >
 >  > Original poster: Fucian-at-aol-dot-com
 >  >
 >  > Hey everyone...Im having some BAD trouble with a SIMPLE circuit...I
 >  > really believe that GOD is keeping it from working for
 > SOME reason...
 >  > Here goes the story: I built the micro sstc by steve ward...Its the
 >  > 4420 based circuit...I built and rebuilt it and then bought a new
 >  > breadboard and made it look GREAT!Formed all my wires all nice
 >  > and...Before i added the 12volt regultor to the board, i wanted to
 >  > test the circuit...I used a 12 volt battery...Since i dont have an
 >  > o-scope i used my DMM with its frequency and voltage...I tested for
 >  > frequency out of the 4420(i have a 555 to start the coil)...I got
 >  > 500khtz out and 12 volts out...I was happy...Did a lil
 > dance...Nothing
 >  > blew up or got warm...I then added a 12 volt regulator and
 > TESTED it
 >  > to make sure it was working...It worked and i wired it into the
 >  > circuit...I tested it....AND TESTED IT!AND UGGGGGGGGGGGGGG.....no
 >  > frequcny at all!
 >
 > At this point, a circuit of what you actually did would be helpful.
 > Were you still running from the battery when you put the regulator in
 > the circuit? Don't forget, they have a dropout voltage of 3V or so.
 > If the voltage to the chips was too low, they may have been refusing
 > to go (undervoltage lockout - I haven't looked at the datasheets).
 >
 > Malcolm
 >
 >
 >   My dmm DID say 60 htz...But it always seems to say
 >  > that when i get close to a xmfr...I got 0 volts out of the
 > 4420 so i
 >  > moved down to the 555 and got 12 volts out and no
 > frequency( stupid 60
 >  > htz BS)...I was stupified...I yannked both ICs out and
 > replaced them
 >  > after testing each part...Everything was fine...This time i got
 >  > nothing AT ALL out of either IC...These were brand new ICs from
 >  > MAXIM(samples)...Again, nothing warm, no explotions...I then found
 >  > anoyher 555 from Onsemi i had left over and put it
 > in...Got 10khtz and
 >  > then nothing...
 >  >
 >  > WHAT IS GOING ON HERE?TELL me its not GOD!SO i BEG you
 > guys to help as
 >  > i have spent so much time( all night till 6am) and LOTSA
 > money buying
 >  > stuff...I even got so happy and made a halfbridge..-dot-complete with
 >  > IRFP460s and bought a new variac cuz i was so DANG excited...
 >  >
 >  > Can i just BUY this from someone?I just need the driver!
 >  > PLEASEEEEEEE!!!Im going mad!I JUST NEED THE DRIVER!!!!I
 > will pay cash
 >  > for it!PLEASE help me!I really need help as im going to
 > can this thing
 >  > and forget tesla coils and my electrical engineering degree and
 >  > all...Ive done EVERYTHING ive been taught to do!WHAT is wrong!?If i
 >  > cant get THIS to work, im no good as an engineer?I guess i
 > should just
 >  > switch majors to psychology and put myself in a mental
 >  > home!LOLOLOLOLOLOL!!!!!!
 >  >
 >  > PLEASE forgive my insanity..Its lait and i have a math test in the
 >  > AM...geeze...Thanks to ANYONE who will help!
 >  >
 >  > Matt
 >  >
 >  >
 >  >
 >
 >
 >
 >