Mailing List flyrotary@lancaironline.net Message #35660
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Re: 2nd Board Cooked
Date: Sat, 24 Feb 2007 15:13:42 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Yes, Kevin
 
Probably not needed, but it costs nothing more to put it in there and things run a bit cooler.
 
Ed
----- Original Message -----
From: kevin lane
Sent: Saturday, February 24, 2007 3:09 PM
Subject: [FlyRotary] Re: 2nd Board Cooked

is the big silver area a heat sink (I assume its not to handle higher amperage)?   kevin
----- Original Message -----
Sent: Saturday, February 24, 2007 11:57 AM
Subject: [FlyRotary] 2nd Board Cooked

After digesting the lessons learned from the first board, I got up my gumption to try another board.  The second board turned out much better although I still had to work the 0.25mm pitch socket manually to get it acceptable.
 
I reordered the placement of components by geographic region rather than by type (capacitor, resistor, diode) as I had for the first board.  This resulted in no repeats of knocking already placed components off their pads.
 
I learned to drop the component on or near the solder pads and then NOT try to move it with the tweezers.  Instead I drop the tip of a pick on the board and slide the pick into the component and thereby move it on its pads.  Ends up that works much better for me rather than trying to lay the component right on the pad (which with no parallax doesn't work well).
 
 
After I did the solder past run, I removed the solder on the .25mm pitch 30 pin socket as it has "slumped" and covered several adjacent pins.  Flux may have seen it draw onto the pins, but I think there was just too much and it would bridge again.  So I removed the paste in that area before popping it in the oven.
 
I then manually soldered on the .25mm pitch socket - again got some pin bridging.  I tried with a solder sucker and still bridging remained.  I was wishing I had some solder wick when I happened to think - Hey! I'll bet if I strip the insulation off of some fine stranded copper wire - I might could make a solder wick.  Well after that was the answer.  It took the solder bridges right off.
 
I did, however, find that SMD pad dimensions for my diodes was off considerably.  The diodes just barely caught the solder on each end.  So redid the board diagram with the correct dimensions this time - I laid a diode on a paper print out and it fit.
 
Now everything looks good, but have not finished with connectors and cutting the board into two pieces.
 
Even though I am starting to get "use" to the 0805 size components, I am still going to back up to the next larger size - since I have the board space - just to make it easier on my nerves {:>).


--
Homepage:  http://www.flyrotary.com/
Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster