On Thu, 08 Oct 2009 13:00:17 -0700, D Yuniskis
wrote:

wrote:

As a rule of thumb, when a monitor has a defective cap, I will replace
the lot of them. As you point out, it's not worth the risk of having
to open the monitor up again.

I prefer Panasonic FM or FC series for replacements. Purchasing from
Digikey, I can redo an entire monitor for under $10, including
shipping. (OK, I seldom replace the 100 µF 450 Volt cap).

I've only seen one of these "bad" (in about 100 monitors).
Despite the fact that they are often manufacture by the same
company who manufactures the other (crappy) caps on the
board! I guess the ripple currents are not as large (?)
The large (rectified mains filter) is handling 120 Hz ripple (and the
pulses from the SMPS). The filter caps on the secondary are handling
100 KHz or greater ripple. As I understand the problem, the ripple
current will cause heating (duh!), which will cause the ESR to rise,
causing more heating, until eventually a poorly made cap will vent.

The mains filter cap has several advantages - much lower current and
much more surface area to dissipate the heat.

PlainBill