[sdiy] How to find a short-circuit? (Vox organ problem)

[jean-pierre.desrochers at ville.quebec.qc.ca]

One thing I often do with this type of problem
specially with shorts in digital circuits supply's lines with lots
of TTL's or CMOS's that have one (or more) of them shorted:

-Unplug power from the device on test
-Put a variable DC power supply on the shorted supply
 line with zero volt applied
-SLOWLY raise the voltage and check with one
 finger the components that start to get too warm
-Shot the DC supply OFF
-Remove those components 
-Put back the external DC 
-Do it again until DC voltage goes normal

Cheers!
Jean-Pierre Desrochers



-----Message d'origine-----
De : "Antti =?ISO-8859-1?Q?=20Pitk=E4m=E4ki=22?= <anpitkam at hotmail.com>
[mailto:"Antti =?ISO-8859-1?Q?=20Pitk=E4m=E4ki=22?=
<anpitkam at hotmail.com>]
Envoyé : 16 mai 2007 15:28
À : synth-diy at dropmix.xs4all.nl
Objet : RE: [sdiy] How to find a short-circuit? (Vox organ problem)


Hi,

First of all, thanks everybody for the great tips!

Steve wrote:

>It would be wise to expect more than one short.
>
>Do the boards plug in, or do you have to desolder them?  If so,
>taking them all out, check that the power supply comes up, then
>try each board in turn...

Yes, the boards indeed simply plug in in this 40-year old organ. This is a 
very good tip, thank you! People at the combo organ discussion group also 
suggested simply plugging out each oscillator card one by one, until I get a

sound out of the organ, if I get. I'll do this, or in fact my friend will do

it because he's checking the organ at the moment. I'll let you know what 
happens. Owning a Vox Continental 2 has been a dream of mine for a long 
time, and I'm really looking forward in getting this instrument to work. Too

bad these are so damn expensive these days, that I had to buy this 
non-working beaten-up Connie. It cost me about 400 euros, but that's a great

price, especially if the prices go up even more.

Antti P.

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