Author Topic: Solder type and heat range on power transistors  (Read 960 times)

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Offline Hawke

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Solder type and heat range on power transistors
« on: December 11, 2016, 03:04:39 pm »
I have two RF transistors needing replaced that I've put off for years because of the heat required to desolder the old ones it just tortures the pcb. I have wafer matched mrf455 and 2sc2960 to put into an old project but as said I've been putting it off. The factory solder requires way to much heat. Is there a flux I can buy to soften this up or anything ? Thanks
 

Online tautech

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Re: Solder type and heat range on power transistors
« Reply #1 on: December 11, 2016, 03:21:31 pm »
I have two RF transistors needing replaced that I've put off for years because of the heat required to desolder the old ones it just tortures the pcb. I have wafer matched mrf455 and 2sc2960 to put into an old project but as said I've been putting it off. The factory solder requires way to much heat. Is there a flux I can buy to soften this up or anything ? Thanks
Welcome to the forum.

They're probably production soldered with that lead free muck.
Try mixing some normal solder with the joints, suck it off and maybe do it again a time or two until you can sucker the holes clean. Do you have a temp controlled iron? Not using too smaller tip ?
Avid Rabid Hobbyist
 
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Offline SeanB

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Re: Solder type and heat range on power transistors
« Reply #2 on: December 11, 2016, 03:58:01 pm »
Chipquick will amalgamate with the existing solder to make it a very low melting point alloy that then is easy to remove with low temperature. A small roll will cost, but for this it probably is worth it. You just need to use solderwick and extra liquid flux afterwards to get it all off, then retin the pads, clean again with solderwick, retin then place the new device and just reflow the solder using more flux. Then clean the area with IPA and it will be done.
 
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Offline Hawke

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Re: Solder type and heat range on power transistors
« Reply #3 on: December 11, 2016, 04:15:03 pm »
Thanks guys and yes I have temp controlled irons and vacum desoldering equipment but the solder on those transistors is evil stuff. I will buy some of the mentioned product to soften the old ones up as it is worth the cost to not torture the pcb. Loving this forum. Cheers
 

Offline David Hess

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Re: Solder type and heat range on power transistors
« Reply #4 on: December 12, 2016, 10:13:54 am »
I have faced the lead free solder situation recently with PC power supplies and have replaced RF power transistors before.

To handle the lead free solder, I mix in some standard SnPb solder and then remove it all with braid.  Then I use a lower temperature of 600F to remove the part.  In both cases I used the largest possible tip for maximum heat capacity and transfer.
 
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Offline IdahoMan

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Re: Solder type and heat range on power transistors
« Reply #5 on: December 14, 2016, 04:08:20 am »

Makes one want use some kind of component socket instead of soldering the component directly to the board.
 


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