Elektor Formant Modular

Problem with fitting a resistor in series with the supply rails is
that the output side of the resistor no longer remains regulated.

A better method would to be to add current limiting circuitry to the
regulator ic's, or fit a couple of transistors in the power rails,
with a small value resistor between the emitter and base as the
current rises of one of them will shut the transistor off it the
current goes too high.





--- In ElektorFormant@yahoogroups.com, "castef@n..." <castef@n...> wrote:
> Hello,
> a good way to avoyd this kind of problem is to increase the internal
resistance of your power supply. You can insert a resistor of a few
hundred ohms in the +15 and the -15 V (but not the 0 V) so the
intensity (and the power) will be limited. With 200 ohms, if there is
a problem in your module, you have a limit of 75 mA, sufficient to
identify a short circuit by analysing the temperature of the
components, but not sufficient to make smoke. If there is no problem,
the module will probably works in spite of the resistors.
> If I remember, the ADSR module has only basic integrated circuit,
not so hard to replace if they are fried.
> A voltmeter is very usefull (well, very very usefull).
> 
> Good luck 
> 
> Stephen
> 
> 
> (from France)
> ---------- Initial Header -----------
> 
> From      : ElektorFormant@yahoogroups.com
> To          : ElektorFormant@yahoogroups.com
> Cc          : 
> Date      : Sat, 18 Jun 2005 13:33:53 -0700 (PDT)
> Subject : Re: [ElektorFormant] Re: PSU's suggestions? (OLD THREAD)
> 
> Hi Mark,
>  
> congratulations first. And to the girlfriend too please.
>  
> 15Volts is 15Volts no matter what PSU you use. Most probable your
ADSR was due to blown anyway. Old modules can be tricky. check all PCB
tracks before powering up I would say. If something is faulty on the
power tracks you might end up giving 30Volts (15+15) to some component
that was designed to be working on 15V
>  
> Dirk
> 
> markfrancombe <mark@m...> wrote:
> Hi again, 
> Time has passed and, my Formant overhaul took a short break because:
> 
> a) I bought a few Blacet modules and have been building them and..
> b) Discovered girlfriend is pregnant, :-)
> 
> BUT... Re: prev thread,(subject line) My Formant PSU is a messy old 
> thing and I asked way back if anyone knew if it could be powered by 
> the Blacet PSU (which I was buying anyway).
> 
> Well, just hooked up an Formant ADSR module to the Blacet PSU...to 
> see.. and er.. no... it didnt work.. there was a funny smell and the 
> IC's got VERY hot before I ripped out the power... so maybe I blew 
> the damn module??
> 
> Now The Blacey is +15 0 -15 and the Formant is +15 0 -15, so WHY 
> WONT IT WORK?? Should I just tidy up the Formant PSU and use it 
> anyway? (It REALLY is a mess) or is there another option?
> 
> mark
> 
> 
> 
> 
> 
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