On 2018/10/07 1:26 PM, John Larkin wrote:
On Sun, 7 Oct 2018 11:58:41 -0700, John Robertson
wrote:

On 2018/10/07 10:36 AM, Jeff Liebermann wrote:
On Sun, 7 Oct 2018 16:08:34 -0000 (UTC), Cursitor Doom
wrote:

https://www.flickr.com/photos/128859...posted-public/
https://www.flickr.com/photos/128859...posted-public/
As you can see, the "world's worst" tag was no exaggeration!

There may be hope for you yet:

1. How many watts is your soldering iron? It looks like the mess
made by too low power or too fine a tip. 75 watt seems about right.

2. Is the soldering iron temperature controlled? If yes, raise the
temperature and work fast. Mine runs at 750F (400C) for 60/40
lead-tin. If no, go shopping and buy a decent adjustable temperature
controlled soldering station. Get a fine tip for fine work, and a
thicker tip for the big stuff (so that the tip doesn't go cold as soon
as you touch the work).

A good soldering station and good hand tools (eg. - strong needle nosed
pliers, shard edge clippers) are indispensable for repairing equipment
properly.


3. Are those 3300uF 25V caps 85C caps or 105C? The photo looks like
85C. If so, they'll last about 6 months inside a hot oscilloscope.

I spotted what looks like "10..." curling over the edge on the edge of
one of the caps, so he is at least using 105C caps. The caps should be
secured though.


4. Clean the enamel off the wires with sandpaper before you solder.

Sandpaper may be too aggressive if a rough grit, that can introduce
scratches to the copper leaking to the potential for breakage. I suggest
using something more like wet/dry emery cloth of about 1000 grit - true,
it is another sandpaper, but less likely to scratch.

I scrape magnet wire with an x-acto knife. That leaves a shiny surface
that wets nicely. I think the professional wire strippers use rotating
knives.

https://www.dropbox.com/s/27px827y9e...nned.jpg?raw=1

https://www.dropbox.com/s/zcbo3i2kro...B_L1.jpg?raw=1

I have a brush that uses fiberglass. Cleans quickly, bends a bit to get
the rounding needed, and doesn't run any risk of nicking the wire.

Something like this:

https://www.ebay.com/itm/191126624992

Also polishes edge connections, etc. a very useful tool.


A serious high-power, controlled temp iron is basic to good soldering.
I like my Metcal.


For regular board work I like my Weller stations with the magnetic temp
controlled tips, I mostly use the #7 medium or thin screwdriver tip.

John :-#)#

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