X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Received: from rwcrmhc13.comcast.net ([216.148.227.153] verified) by logan.com (CommuniGate Pro SMTP 5.1.6) with ESMTP id 1860638 for flyrotary@lancaironline.net; Sat, 24 Feb 2007 15:10:39 -0500 Received-SPF: none receiver=logan.com; client-ip=216.148.227.153; envelope-from=n3773@comcast.net Received: from rv8 (c-24-21-141-28.hsd1.or.comcast.net[24.21.141.28]) by comcast.net (rwcrmhc13) with SMTP id <20070224200953m13006d46fe>; Sat, 24 Feb 2007 20:09:53 +0000 Message-ID: <003d01c7584f$beec0cf0$1c8d1518@rv8> Reply-To: "kevin lane" From: "kevin lane" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] 2nd Board Cooked Date: Sat, 24 Feb 2007 12:09:48 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_003A_01C7580C.AE477940" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 This is a multi-part message in MIME format. ------=_NextPart_000_003A_01C7580C.AE477940 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable is the big silver area a heat sink (I assume its not to handle higher = amperage)? kevin ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 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 {:>). Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.dmack.net/mazda/index.html -------------------------------------------------------------------------= ----- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ ------=_NextPart_000_003A_01C7580C.AE477940 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
is the big silver area a heat sink (I = assume its=20 not to handle higher amperage)?   kevin
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Saturday, February 24, = 2007 11:57=20 AM
Subject: [FlyRotary] 2nd Board=20 Cooked

After digesting the lessons learned from the = first=20 board, I got up my gumption to try another board.  The second = board=20 turned out much better although I still had to work the 0.25mm pitch = socket=20 manually to get it acceptable.
 
I reordered the placement of components by = geographic=20 region rather than by type (capacitor, resistor, diode) as I had for = the first=20 board.  This resulted in no repeats of knocking already placed = components=20 off their pads.
 
I learned to drop the component on or near the = solder=20 pads and then NOT try to move it with the tweezers.  Instead I = drop the=20 tip of a pick on the board and slide the pick into the component and = thereby=20 move it on its pads.  Ends up that works much better for me = rather than=20 trying to lay the component right on the pad (which with no parallax = doesn't=20 work well).
 
 
After I did the solder past run, I removed the = solder on=20 the .25mm pitch 30 pin socket as it has "slumped" and covered several = adjacent=20 pins.  Flux may have seen it draw onto the pins, but I think = there was=20 just too much and it would bridge again.  So I removed the paste = in that=20 area before popping it in the oven.
 
I then manually soldered on the .25mm pitch = socket -=20 again got some pin bridging.  I tried with a solder sucker and = still=20 bridging remained.  I was wishing I had some solder wick when I = happened=20 to think - Hey! I'll bet if I strip the insulation off of some fine = stranded=20 copper wire - I might could make a solder wick.  Well after that = was the=20 answer.  It took the solder bridges right off.
 
I did, however, find that SMD pad dimensions = for my=20 diodes was off considerably.  The diodes just barely caught the = solder on=20 each end.  So redid the board diagram with the correct dimensions = this=20 time - I laid a diode on a paper print out and it fit.
 
Now everything looks good, but have not = finished with=20 connectors and cutting the board into two pieces.
 
Even though I am starting to get "use" to the = 0805 size=20 components, I am still going to back up to the next larger size - = since I have=20 the board space - just to make it easier on my nerves = {:>).
Ed Anderson
Rv-6A N494BW Rotary = Powered
Matthews,=20 NC
eanderson@carolina.rr.comhttp:/= /members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.dmack.net/mazda= /index.html

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Homepage:  http://www.flyrotary.com/
Archive and=20 UnSub:  =20 http://mail.lancaironline.net/lists/flyrotary/
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