I've made up dozens of these supplies in all kinds of layout
configurations and have found them to be bomb-proof. In fact I have
never had a failure yet, they work every time. The circuit will work
without the snubber R6/C3.
There must be some simple answer to your problem. It seems to me as
if the 555 might not be doing any switching, or doing it incorrectly.
Or as you say the FET is not all it's cracked up to be, or the diode
is not fast enough. Check the value and rating of your inductor.
The FET should not get too hot. Usually it will run cool enough for
you to hold it.
John S
On 18 Nov 2011, at 19:43, Imbanon wrote:
Hi all.
Yeah, another thread about this supply.. http://www.ledsales.com.au/
kits/nixie_supply.pdf
I know I could and should have made that Maxim power supply, but I
didn't. So now I'm stuck fixing this with loads of spare parts I've
got... except for the FETs..
Anyways, the supply isn't working. The first one I made worked just
fine for 15 minutes, powering 6 IN-14 at 170 volts (multiplexed). Then
I set it to 200 volts (to get RMS of 2mA), which worked for 5 minutes,
and then smoked and failed.
I made another on a quick PCB, which just smoked immediately when I
switched it on. The same thing happened to the newest, breadboarded
one.
The MOSFET seems to overheat instantly and smoke out. Having nothing
to lose (except the molten hole in the breadboard), I left it powered,
to see the diode smoking next. Aparently, its still in working order
(so says the multimeter).
Heat sinking FET only makes it last longer in not working state before
it smokes.
I tried replacing inductors, 555s, diodes, transistors..
What the F**K do I do people? Losing my head here!
And yeah, I'm powering it at 12 volts, tried 5. Output is always 3-6
volts.
Thank you for any help provided!
Imbanon
--
You received this message because you are subscribed to the Google
Groups neonixie-l group.
To post to this group, send an email to neonixie-l@googlegroups.com.
To unsubscribe from this group, send email to neonixie-l
+unsubscr...@googlegroups.com.
For more options, visit this group at http://groups.google.com/
group/neonixie-l?hl=en-GB.

JS Design
54 Brambledown Road
Wallington
Surrey
SM6 0TF
T+F +44 (0)20 8773 4779
www.jsdesign.co.uk
--
You received this message because you are subscribed to the Google Groups
neonixie-l group.
To post to this group, send an email to neonixie-l@googlegroups.com.
To unsubscribe from this group, send email to
neonixie-l+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/neonixie-l?hl=en-GB.
inline: jsd-email-eye.jpg
