The tants had a really good high frequency response IIRC -- good for
filtering out noise as well as 60Hz.
My technique was to follow the power buss on the circuit board and find an
arbitrary mid-point that was away from any critical wiring and use a dremel
tool to sever it.
Find out which half had the short and proceed until you had three or four
caps to test. Unsolder one lead and lift the leg and test the power buss
again.
I could usually find a dead cap in 10-15 minutes. A good friend of mine
nearly fainted when I dug into his Odyssey although he had thought the
problem was in the power supply and had disassembled it. Took me longer to
put that together than to find and replace the dead tant.
Scrape the traces on each side of the dremel cut and solder a bit of solid
wire to bridge the gap.
Dave
> -----Original Message-----
> From: ModularSynthPanels@yahoogroups.com
> [mailto:ModularSynthPanels@yahoogroups.com] On Behalf Of
> Richard Brewster
> Sent: Sunday, September 27, 2009 6:32 AM
> To: ModularSynthPanels@yahoogroups.com
> Subject: Re: [ModularSynthPanels] ChaQuo Wiring Question...
>
> I'd not use any tantalum caps. Their main benefit is the
> smaller size
> vs electrolytic of the same specs. They also cost more. I
> have one of
> my own tales from the days of yore. I used to hand-build audio and
> video synthesizer circuits in the seventies. These were all
> prototypes
> and needed plenty of power line bypassing. At one point we
> used a bunch
> of 100 nf Panasonic tantalums. We might put 20-30 of them on
> a board.
> And yes, they did fail by shorting out. But unless it fried
> and burned,
> we could not tell which one failed. So, one by one, each had to be
> clipped out until the bad ones were found. Then all the "good" ones
> that had been removed too had to be replaced. Needless to say, we
> stopped using the tantalums. If you do want to use some, I'd
> recommend
> ones with at least a 35 volt rating.
>
> Richard Brewster
> http://www.pugix.com
>
> mcb, inc. wrote:
> > On Sat, 26 Sep 2009, Scott Deyo wrote:
> >
> >
> >> Yeah, I torched a polysty on mine too. That's probably the
> culprit. Polysty's
> >> and tantalums are bummin' me out lately...
> >>
> >
> > Speaking of tantalums, came across this interesting tale from
> > days of yore:
> >
> >
> http://www.designnews.com/blog/Made_by_Monkeys/23362-Do_You_Wa
> nt_Butter_On_Those_Capacitors_.php?nid=3073&rid=398497
> >
> > --
> > Monty Brandenberg
> >
> >
>
>
>
> ------------------------------------
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