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Re: PSU's suggestions? (OLD THREAD)

2005-07-25 by markfrancombe

Thanks for the advice.. I will definately give the resistor idea a 
go...
As for having a voltmeter... well I DO have one, but to be honest, I 
really don't know how to use it ha ha!!! (Yes... and I'm overhauling 
a dusty old 70's synth!)Infact, due to the fact that it is now in 
bits, I was wondering how I can test...
A) DId I fry the ADSR?
B) IN future how do I know if the ADSR (or any module) is working, 
when I hook it up to the PSU.

The ADSR was a silly module to first hook up, cos it needs 
connections to other modules to know if its working... (Idont have a 
keyboard.. so I need to modify it so it will accept a gate signal, 
not just the Formant Internal Keyboard trigger, from the Interface 
board...)but from a sequencer (mobius for example).

But I DO want to know...specifically.. IS someone here powering their 
formant from a 3rd party PSU, and is ANYONE useing the Blacet? (Or 
know for DEFINATE that its OK) SOrry if Im being particularly obtuse, 
but Im trying not to blow another module... (If indeed that is what I 
have done)







--- 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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