Re: OT: the capacitor curse


Robert Simpson
 

Yup, My 24 inch LCD PC monitor and my wife's 22 inch (she uses it a lot less often), my wife's PC, my daughter's pc etc., and many more all came free to me (mid to upper pentium 4s, some dual core). Five to ten dollars or so in caps and then good for years more use. Several businesses throw them away as not cost effect to pay for repairs. As a retired person's hobby well worth it.
Bob

--- In TekScopes@yahoogroups.com, Bert Haskins <bhaskins@...> wrote:

On 04/14/2013 01:13 PM, vdonisa wrote:

While I was busy with refreshing the 2467B, my better half kept
complaining that the cable box is rebooting itself every 20 minutes or
so. Since I own it (not leased) I figured out I should do something
about it myself as its past warranty period.

Guess what - just to confirm that I was doing some useful work with
re-capping the scope, I found this inside the cable box (Scientific
Atlanta):

http://groups.yahoo.com/group/TekScopes/photos/album/1306124308/pic/2092672805/view


I replaced the vented 470uF/10V and now the box seems to be stable,
however while I was resizing the photo to upload to the group I
noticed that the brown cap behind the Rubycon seems to be bulging so
I'll have to open the box again....

Which brings me to one question. This box is "ROHS", which makes it a
pain to (un)solder anything there. The freaking alloy they used needs
to be heated in excess of 400C in order to flow, and it doesn't seem
to properly adhere to anything except the inside of the metalized
holes :-(

I remember seeing once some advertising for a "magic solder" that you
would use on such joints and would combine with the existing ROHS one,
dramatically lowering the melting point and wetting properties of the
resulting alloy. However I cannot find it now, does anyone here know
where I could find it again?

Thanks,
Valentin VE3VDO
Sadly, this does not appear to be unusual, many late model flat screen
tvs seem to eat filter caps for breakfast.
Same is true for many other consumer product items.
I think the market is targeted to the "use it toss it" crowd and a
two-year product life time is the norm.
Some call this " going green".

I'm not even a service guy and I replaced at least forty caps in the
last twelve months.
I do not replace caps just because of age.

One that I thought was interesting was on a friend of a friends very
heavily used Fender amp.
The original caps had lasted for over a decade and were down to less
than 30% of their rating.
The replacement caps were much smaller but as it turned out they only
managed to last one year.

I have had very little trouble replacing parts though, at least those
that are large enough to see.
One trick that I use is to first add solder to the connection and then
remove it with the solder sucker.
I use NoClean 60/40 and sometimes use extra liquid flux.

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