[sdiy] Can I use two 1/4w resistors instead of one 1/2w ?

[Gil W.]

So overall, should the freeze indicate either contact or power supply problems ?





--- On Tue, 6/23/09, Dave Kendall <davekendall at ntlworld.com> wrote:

> From: Dave Kendall <davekendall at ntlworld.com>
> Subject: Re: [sdiy] Can I use two 1/4w resistors instead of one 1/2w ?
> To: "Gil W." <gil_we at yahoo.com>
> Date: Tuesday, June 23, 2009, 2:48 PM
> Hi Gil.
> 
> 
> You've probably already thought of this but, I had an EPS
> that went 
> bad, back when they came out. The ensoniq service tech said
> that a 
> common source of failure was the multipin power headers
> between boards 
> getting corroded. The pins had gone horrible and green on
> mine (!)
> The ICs also worked their way out of the chip beds very
> often, and had 
> to be re-seated.
> 
> cheers,
> Dave
> 
> 
> On Jun 23, 2009, at 12:39, Gil W. wrote:
> 
> >
> > Of course,
> > http://itec.uka.de/~buchty/eps-sch.pdf
> >
> > This synth arrived with a severe power supply damage.
> It had diode CR2 
> > short out, Fuse F3 bad, C14 (470uf) blown (the top of
> the cap swelled)
> > and the 1/2W resistor I mentioned (R5), fried and non
> conductive.
> >
> > I of course replaced them all (R5 is currently
> replaced with the 
> > combination of three resistors). The instrument works
> for a few 
> > minutes and than freezes...
> >
> >
> >
> >
> >
> >
> >  I did find the original 1.2K 1/2W  resistor
> fried (along with other 
> > components) when I
> >
> > --- On Tue, 6/23/09, Needham, Alan <Alan.Needham at centrica.com>
> wrote:
> >
> >> From: Needham, Alan <Alan.Needham at centrica.com>
> >> Subject: RE: [sdiy] Can I use two 1/4w resistors
> instead of one 1/2w ?
> >> To: "Gil W." <gil_we at yahoo.com>,
> "Magnus Danielson" 
> >> <magnus at rubidium.dyndns.org>,
> synth-diy at dropmix.xs4all.nl
> >> Date: Tuesday, June 23, 2009, 2:19 PM
> >> This 'resistor' is getting hot
> >> because something else is drawing too
> >> much power (or the design pushes the 1/2W resistor
> to its
> >> limits ???).
> >> Maybe some semiconductor is shutting down due to
> it also
> >> overheating?
> >> Maybe there is a regulator doing exactly as it
> should and
> >> going into
> >> thermal overload due to some fault further into
> the
> >> circuit.
> >>
> >> Any chance of the circuit diagram instead of
> guessing what
> >> this resistor
> >> is feeding?
> >>
> >>
> >> -----Original Message-----
> >> From: Gil W. [mailto:gil_we at yahoo.com]
> >>
> >> Sent: 23 June 2009 10:31
> >> To: Magnus Danielson; synth-diy at dropmix.xs4all.nl;
> >> Needham, Alan
> >> Subject: RE: [sdiy] Can I use two 1/4w resistors
> instead of
> >> one 1/2w ?
> >>
> >>
> >> They get hot, but do not fry...
> >>
> >> The system freeze happens about 10 minuted after I
> power it
> >> up. The
> >> system works perfectly before it freezes.
> >>
> >> What to check for ? bad regulators maybe ?
> >>
> >>
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