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.
Tin the wire ends before attaching to a lug or PCB rivet.
The invented bridge rectifier was poorly made for the space allowed, and
those bridge modules are readily available. If you need to make a bridge
module wrap the leads at least one loop around the others for a
mechanical junction prior to soldering. Then there less risk of a solder
joint breaking and introducing random loose parts into your equipment...
I've dragged some of the local hams into my palatial office and
demonstrated how easy it is to solder properly with a decent soldering
iron. They're usually amazed at how well THEY can solder using my
equipment. That's when I discover that they're using something from
Radio Shack or that came with their childhood wood burner kit. I just
did a quick scan of what's available on eBay and noticed that they now
have OLED display aftermarket temp controllers for HAKKO soldering
irons. I'm tempted:
https://www.ebay.com/sch/i.html?_nkw=soldering+station+temperature+controll ed
This looks handy - so I've ordered a couple for the shop:
https://www.ebay.com/itm/352464262209
Nice to be able to check calibrations by comparison.
Also, if you don't have a hot air SMD workstation, this might be a
good time to get one because they often include an adjustable
temperature controlled soldering iron.
John :-#)#