[PlanetCCRMA] Delta 1010 replacement capacitor part numbers

[Tom Anderson]

>
>
>This one is 470 uF, rated for 63v ... what would be an appropriate value
>> to look for?  And if we decide to do this, should we change the other
>> one that's just like it and which looks like it's part of the same
>> group, but which doesn't seem to have sustained damage?
>  
>
(delurking...   wait for it...   poof!)

I found the 470uF capacitors on my LT1010 (Rev B, 0307)
and they are rated at 16V and 105 degrees C.  My capacitors
look fine and work fine, and my board is powered up
all the time.  Matt mentioned 63V at 470uF, this would
almost certainly not fit on my board.  The capacitors on
my board appear to be one of the standard sizes:
a metal can that is 8mm diameter and 12mm tall.

I'm assuming this capacitor is for filtering
the +/-12V supplies, in which case, 16V is a marginal rating.
The rule of thumb is that the capacitor rating should be
double the working voltage.  75% is really too high.
25V and 105 degrees C would be better.

The capacitor failures can be caused by too much AC
current in the capacitor.  The specification for this is
'max ripple current'.  I don't know how much
ripple current there is in this design,
but high quality, low effective-series-resistance
capacitors can handle more ripple current.  Also,
larger, higher voltage capacitors with the same value
can usually handle more ripple current.  If you really
have a 63V part (which I expect would have to be
in a larger can than mine) the reason for the high
voltage may have been to get a part that can
tolerate more ripple current.

For a replacement on my board, I would recommend
either of these two parts:

Manuf Part No.   Manuf       Digi-Key Part No. price
UPW1E471MPD6     Nichicon    493-1827-ND      $0.69
EEU-FC1E471L     Panansonic  P10274-ND        $0.89

http://www.digikey.com is a great supplier for this type
of part, they are very happy to sell you a small
quantity of parts.  They have great phone service and
many delivery options.

I selected the parts above because I believe that
they would work and fit on my board.  Both
Nichicon and Panasonic make capacitors with
excellent quality.  These capacitors
are both 8mm in diameter and 20mm tall, which is
slighly taller than the capacitors on my LT1010,
but not so tall that they would bump into anything
else in my computer. They are 25V, 105 degree C parts,
and have an ESR of 0.065 Ohms.  The datasheets are
available online at the no-hassle Digi-Key web site.

Replacing the capacitors requires some skill with
a soldering iron.  These capacitors are polarized,
just like batteries, and can explode if installed backwards. 
There is a + or - sign on the little label that marks the
polarity.

-Tom Anderson