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RE: Feedback SSTC failure!



Original poster: "Jan Wagner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jwagner-at-cc.hut.fi>

Hi,

 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: 31. heinäkuuta 2003 4:27
 > To: tesla-at-pupman-dot-com
 > Subject: Feedback SSTC failure!
 > Hey List,
 >
 >         I've spent a total of about 26 hours working on a
 > SSTC board centered on Justin and Aron's feedback design. The
 > schematics that I used were from Steve Ward's site. I have
 > the board stuffed, and ready to go. However, not
 > even
 > the LED will fire up. With 12 volts in, I am getting 8 volts
 > out of the GL7805 (should have 5 volts here), and only 12
 > volts out of the LM317 (should have 15 volts). Also, the 317
 > is getting hot. The square wave coming out of the 555 is very
 > messy to say the least. Even adjusting the pot. on the power
 > supply will not give me the right voltages out of the
 > regulators.

Watch out that the heatsink or back tab of the LM317 isn't accidentally
grounded. And note that the pinout of the two regulators is different! Easy
to mix up the pins... In addition, with 12V into the LM317 you can't get 15V
out (probably you meant it the other way round)

You should try running the voltage regulator sections without the real load
connected, maybe just a 470 Ohm resistors or similar. If it still gets hot
then there's a prob with the regulator setup.

Good luck!
cheers,
  - jfw

--
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  high voltage at http://www.hut.fi/~jwagner/tesla/
  Jan OH2GHR - GSM +358-41-4682893
  jwagner-at-cc.hut.fi - Jan.Wagner-at-cern.ch