Hardware Hobbyists vs. Emulator Jockeys

Tony Duell ard at p850ug1.demon.co.uk
Fri Jun 19 13:59:09 CDT 2009


> > Whatever have you done to it? AFAIK the 11/70 has switching  
> > regulators as
> > standard (my 11/45 certainly does). Not the normal design of SMPSU (in
> > that there's a big mains-frequency trasnformer on the input), but  
> > it's a
> > switcher none-the-less.
> 
>    Yes...Huge transformer, big bridge rectifiers, LM723, big series  
> pass transistors...that says "linear" to me. :)  I've never gotten  

But 'big series inductor and flyback diode' says 'switcher' to me...

> deeply enough into the circuit I guess.  I've been a DEChead all my  
> life, but still I learn something new from you guys every day!!

I had to understand the cirucit after one of my -15V regulators almost 
literally exploded when I was debugging it. I made the silly mistake of 
disabling the overcurrent trip (lifted the collector of the sense 
transsitor), not realising the crowbar was firing. The result was 
transistors blown apart, a dead 723 -- and a blown fuse. Yes, I did get 
it going again (and even found out why the crowbar was firing).

-tony



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