Elektor Formant Modular

Hi,

The 5V regulator can be as simple as using a 7805 (3-legged device) and a
couple of capacitors. The purists out there will shirk at this approach but
for 99% of us it will work absolutely fine. It will put a bit of a load on
the +15V rail because that is where the regulator will run from and you will
need a small heatsink on the 5V regulator to handle the 7V or so voltage
drop across it. Don't be put off, it is pretty straight forward and will
only cost a $1 or so per VCO. So if you want to run with an external +/-15V
supply then go ahead. I can give you a schematic if you need one.

If the Formant power supply you already have is the original then looking at
the pcb you will see 3 ic's, all 723. One each for +/15V and one for the 5V.
This is a straight forward design and as long as the pcb and components are
clean then it should work fine. You should check all the electrolytics for
bulging or leakage and replace them if they look suspect. Also double check
all the wiring to the external power transistors and make sure that is all
clean and good. If on a common heatsink, then double check that they have
insulation components on them (usually black or white plastic looking
washers and either a mica (clear material) or silicon (grey material) sheet
between the transistor and the heatsink.

If all checks out then the supply should work fine.

Best Regards

(Mr) Laurie Biddulph

Elby Designs
ABN: 70 022 727 605
http://www.elby-designs.com

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----- Original Message ----- 
From: "markfrancombe" <mark@...>
To: <ElektorFormant@yahoogroups.com>
Sent: Tuesday, July 26, 2005 9:36 PM
Subject: [ElektorFormant] Re: ...but dont forget my PSU post.. (now Help
with Voltmeter...?)


> "Laurie Biddulph" <elby_designs@o...> wrote:
> If I recall correctly, the VCOs
> > are the only modules that ALSO need a 5V supply. It would be fairly
> trivial
> > to add a 5V regulator to each VCO and run everything from +/-15V.
> >
> > The Formant used a popular 723 regulator design as it is stable and
> can be
> > adjusted easily.
> >
>
> ahhGh! tHIS WAS EXACTLy what I didnt wanna hear...I certainly did NOT
> know that the VCO needed 5v... It maybe a trivial thing (to make a 5v
> regulator) for you clever electronix wizards.. but I have no idea
> what you sayin!
>
> I think that has pretty much decided it for me, I HAVE to tidy up the
> current formant PSU that I have, put it in a box, sort out a wire
> distro network (currently its nailed to the side of the box, like a
> Norwegian Blue, and power is distributed to the modules via great big
> blobs of solder!!
>
> Thanks for saving me a headache later...
>
>
>
>
>
> Yahoo! Groups Links
>
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>
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>