iFixit - Active Questions With Device Skills

Soldering: Hair dryer for logic board reflow?

Tue, 07 May 2013 21:23:56 -0700

Okay, so I had some time while I was waiting for parts to complete a few more projects. I did my daily browsing through "Answers" and thought it is time to clear up the debate about using a hair dryer for reflow purposes. There are plenty of question and answers about using a hairdryer to reflow either a X-Box or an iPhoneor any other device. To determine what temperatures are produced by either instrument, I assembled a few tools of my own. For this test I used my Dual Temperature 1500Watt heat gun, my families Goodies 1875Watt 2 speed hair dryer, my Lutron TM902C thermometer (range -50deg C to 750deg C), and a few left over ceramic tiles as insulators.

I went ahead and sandwiched the end of the Type K thermocoupler between the ceramic tiles. This way I tried to eliminate variances caused by ambient temperatures as much as possible. It also protects the probe end from to much heat exposure.

Ambient temperature in my shop during this test was 23deg C (73.4deg F). Pretty mild day for South Texas:-)

First heat source I tested is the Goodys 1875watt 3speed hair dryer. It is set to Hot on high speed.

At a distance between the heat source and the thermocoupler of 3/4" (19mm) the maximum temperature it reached was 63deg C (+/- 2deg C by moving the hair dryer in a back-and-forth motion across the thermal probe) (145.4deg F)

Next up is the Dual Temperature 1500Watt heat gun. I used the same setup with the same distance between the heat source and the probe. With a distance of 3/4" (19mm) and the heat gun set to the first speed settings, the maximum temperature reached was 100deg C.(212deg F)

With the heat gun speed at stage 2 the maximum temperature measured was 240deg C.(464deg F) The picture is somewhat deceiving since the angle of the heat gun is increased, so it appears as if it was directly over the thermocoupler. Proper distances have been maintained.

To determine if a hair dryer was sufficient to reflow a board, I picked the solder available in my shop. It is the Sn-Ag-Cu (Tin-Silver-Copper) solder, that is also used by two thirds of Japanese manufacturers for reflow, and has a melting range of 217–220deg C or 422-428deg F . Lead containing solder, like the 63/37 Sn/Pb used principally in electrical/electronic work, has the lowest melting point of all the tin/lead alloys at 183deg C or 361.4deg F. I do recognize that the solidus quantifies the temperature at which melting of a substance begins, but not necessarily the substance is melted completely, is lower than the melting point, but this temperature is usually just a few degrees lower than the melting point

References are here and here

Hopefully this will make a definite case against using a hair dryer for any reflow attempt. It will not reach the temperature required to reflow any logic board. Of course this is just informational for those that wondered about this in the first place. Thanks for a great forum.

⟐ Commented May 7, 2013 at 9:23 pm -0700

Soldering: removing LED from circuit

Tue, 04 Dec 2012 06:04:57 -0700

have any idea about easily removing LED from ciruit board, because its too risky to remove like IC leg prints...

⟐ Edited December 4, 2012 at 6:04 am -0700

software: professional editing video and photo software

Sun, 01 Apr 2012 06:54:46 -0700

i know this is not a repair question but i know many of you'll tecnitian know about computer software to edit,create,combine, and make professional videos and media.

⟐ Edited April 1, 2012 at 6:54 am -0700

Lion OSX: OS Lion is available for download

Thu, 19 Jan 2012 21:32:14 -0700

Lion became available this morning. At 9:05 it took 20 minutes. Download time is running an hour and forty five minutes. No telling how long it will take once email notifications are sent out. Just wanted to notify ya'll.

The incapacity of Lion to allow the functioning of the Power PC applications may be a major problem, the problem is the abandonment of Rosetta. Rosetta allows Power PC apps to run with an Intel processor. Before doing this update, it would be wise to check which applications, which small utilities will not function any more and to benefit from it to do the housekeeping or to find an equivalent with the Intel code of it.

CultOfMac offers a simple solution to track all this software. Make the following command in the terminal:

system_profiler SPApplicationsDataType >~/Desktop/MyFileTypes.txt

It will create on your desk a textual file " MyFileTypes.txt" that will contain all the list of the applications of your computer. Open and do a search for the occurrence " Kind: PowerPC".

All the software that have this label will not function on Lion.

For those who still imperatively need a Power PC application and who want nevertheless to upgrade to Lion, I suggest that they keep a partition Snow Leopard on their machine.

I ran this Terminal command and the list of programs that won't work on my machine was very extensive. Even my Adobe CS 2 won't work. I'll be installing this system on something that doesn't matter. This appears worse than my transition from system 9 and the loss of all those programs collected for so many years. I'm very disappointed with this revelation of Lion.

UPDATE

Lion is not a upgrade only. It will install a full version. I tried burning it onto a DVD but got media errors twice. I moved it to an external firewire drive to move it around. I didn't think it installed at first, it gives you an app that tells you what programs won't run with it. It requires a couple of restarts to install. The install took 22 minutes. It automatically opens migration assistant on the first boot.

To my surprise, migration assistant moved over all the apps that it says won't work so I will have to go in and clean them all out.

⟐ Commented January 19, 2012 at 9:32 pm -0700