On Wed, 22 Sep 2010 05:05:19 +0000 (UTC), Sergey Kubushyn
wrote:
Jeffrey Angus wrote:
On 9/21/2010 11:29 PM, Sergey Kubushyn wrote:
I recently restored and fully recapped two Kenwood KA-9100 amps. All the
boards are phenolic and I used solder braid on them.
And they are not multi layer boards with 0.010" traces.
They are not. There is no such thing as _phenolic_ multi layer boards with
0.010" traces.
Not yet. Some experiments in printed semiconductors and 3D circuits
use multilayer boards. However they don't use solder. They're
stapled together. They're also intended to be throw away assemblies,
so I wouldn't worry about repair.
BTW, solder braid is very useful on _ANY_ board, including multilayer ones
with 0.010" traces. It requires some skills of course but everything does. I
do use it all the time.
I've been soldering for about 50 years, so I suspect I'm sufficiently
experienced to have made all the usual mistakes (several times). It's
not the lack of skill. I have no problem using braid on large objects
with small heat sinks. I have nothing but problems using braid on
small objects attached to large heat sinks. I this case, there's a
small leaded capacitor, connected to a rather large copper heat sink
of the power bus inside the PCB. You can see the effect when
unsoldering the capacitor leads. The ungrounded hot lead comes out
easily. The grounded lead is far more difficult. If the capacitors
are near the CPU and on a power bus, then both leads are difficult.
Braid is also quite suitable for unsolder connections where the solder
is easily accessible and exposed to the braid, such as large xformer
pins, terminal strips, wire terminals, some IC sockets, tube sockets,
etc.
Also remember that this is for what appears to be a beginner at
repair. It's easier to explain how to operate a solder sucker than
braid.
I forgot to mention the desoldering bulb, another device that barely
works:
http://www.amazon.com/Weller-Desoldering-Bulb-Solder-Off/dp/B00011TUZY
The only good part is that it's great finger exercise (I play piano).
I recently purchased one of the contrivances:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220664298701
It's a solder sucker hung on the back end of a hollow soldering iron.
It took a while to discover what was wrong with this idea. The amount
of vacuum generated is dependent on the unsuck to suck ratio of air
volumes. With an ordinary solder sucker, where the tip is close to
the piston, the ratio is rather large, thus offering a good vacuum.
Not so with this contrivance, as the volume of the hollow tube adds to
both volumes and results in much less vacuum. A larger diameter
piston or shorter soldering iron barrel would have made it work
better, but as it stands, the design sucks. 30 watts also seems
underpowered, the tip is too big, and it takes 10 minutes to warm up.
I haven't used it much, but I suspect that it will clog with dross
near the entrance to the solder sucker.
It is not the rifle that shoots way off the target, it is the shooter.
True. However, I would rather use a guided missile (fancy desoldering
station) than to go off plinking at the target (solder braid).
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558