1176 Power supply question (Mnats board)
« on: January 15, 2007, 03:21:14 PM »
Hi everbody,
I have just stuffed mnats board with passive components (so no transistors FET or ICs) apart from the voltage regulator (7824) and the Zener diode.
I am using a 24-0-24 transformer (30VA) and I am getting good regulation out of the 7824 (around 30V) but I am not getting anything close enough to -10V on the zener output (iam actually getting 8.3V).
I am not using (for now as I am waiting for it to be delivered) tha suggested  zener diode (which as far as I know is low impedance) but I am using a common BZX10C zener diode instead.
I have checked the resistors (R85-R86-R87-R88) although I have matched them using my multimeter and they all seem fine.
would that be the case where the zener is JUST NOT RIGHT or shall I start looking for something more detailed?
any suggestion will be more than welcome!
Many thanks,


1176 Power supply question (Mnats board)
« Reply #1 on: January 16, 2007, 03:02:14 PM »
it looks like I am keen on making silly mistakes..
I found what it was and I am posting hoping this might be of help to someone.
I soldered the 2 caps C24 and C26 (just BEFORE the zener diode) the other way around..


1176 Power supply question (Mnats board)
« Reply #2 on: January 16, 2007, 04:35:19 PM »
Glad you found your mistake !!!  :thumb:
Greg Stein
New Orleans, LA


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