[sdiy] Re: Tantalums, VERY IMPORTANT to all DIYers

[Tom Corbitt]

In my experience, there are two mistakes that I see people make over
and over again with tantalum caps.

#1 SMD caps have a band marking the POSITIVE terminal, not the negative.

#2 The voltage spec'ed on tantalum caps is frequently the peak, not
the working voltage (it's usually around 70% of the number given) As
with many things in life, I learned the hard way to always always
always check the data sheet before use.


tom




On Fri, Jun 12, 2009 at 10:08 AM, David Anderson<andersdl at buffalo.edu> wrote:
> Gil,
>
> Have you measured the voltage levels at the caps? I don't know anything
> about the circuits where you replaced the 16v caps but if they're on 15v
> lines, that seems too close to me. And, of course, tolerances on older parts
> were considerably looser than most of the stuff we get these days.
>
> David
>
> Gil W. wrote:
>>
>> Please note that out of my experience, some modern tantalums will
>> BLOW or SHORT if replaced with old tantalums, in some locations in
>> the circuit, even when the voltage rating of the new replacement
>> tantalum is higher !!
>>
>> I had this occurring in both my Prophet 5... and now IN MY CS20M !!
>>
>> I spent a few hours trying to find why my CS20M didn't initialize,
>> when I found that a few 10uf/25v tants I used as replacements for the
>> stock 10uf/16v has shorted out ! One even blew up CAUSING ACTUAL FIRE
>> INSIDE THE SYNTH !!!
>>
>> These problems were solved when I dropped 10uf/35v tants instead (the
>> schematics calls for 16v tant caps....). I then recalled having the
>> very same issue when I recapped my P5 !
>>
>> So, beware and always keep this in mind ;)
>>
>>
>>
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>>
>
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