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a try to repair a driver.

Mannitu78

Member
Joined
Dec 19, 2019
Messages
78
Points
8
Hello folks.
I accidently damaged a nice laser driver. Instead of a diode i hooked a small 5V electromotor on it, i wanted to see if it makes a good testload. View seconds later theres was a little smoke and the black part with the 8 pins came off, obviously its soldering points got too hot and that little part was like "F... that im leaving".
Now this part isnt particularly expensive, but i think it might be a good practice to solder such delicate and small things. Im not even sure if it is salvageable. I tried following so far:
i set the part exactly in the position it was and then tried to heat the board up from the backside, hoping the heat gets through and melts this soldering points again. Now that didnt work, board is thicker as you might think and i only have this 30w crappy soldering iron. I do have a heatgun that goes to 600 C, problem even on lowest air volume setting it puts out a lot of air. Also it has huge diameter at the air outtake, more than an inch.

Plus i dropped that thing and now i dont know which way that thing(i think a transistor)was soldered to the board.
Can anyone maybe give advice how to proceed or guess if it is still working?
thank you.(edit yeah i should admit im a soldering noob. I managed to desolder a few caps and coils from an old mainboard and PSU over the last weeks, but thats it)
 

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Commander J. Bloodmaker

Active member
Joined
Apr 14, 2021
Messages
137
Points
28
I use resolder flux when changing stuff out. Takes almost no solder to do, just the tiniest amount. I slather the resolder flux on like no tomorrow. Helps to keep everything a little cooler, while keeping most of the heat on the tip where I want it. I buy it in needled bottles, so nice for aiming it where I need it. For me the key is a hotter iron than normal, and working faster with the resolder flux. I'm not perfect, and do mess up, but I usually can get it swapped out without to much hassle.
 

Mannitu78

Member
Joined
Dec 19, 2019
Messages
78
Points
8
i havent even heard the word resoldering flux so far. So whats the best way to heat it up, from the backside? Cause this stuff is way to tiny to fummel around with my iron in. I feel i need more than a 30w iron then. How would you proceed in that case?
 
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Commander J. Bloodmaker

Active member
Joined
Apr 14, 2021
Messages
137
Points
28
Get better tips and a better station. Re- solder flux is super clean and requires no clean up, but really only works on pre-soldered stuff, like when repairing and replacing parts. I use a needle point and set my iron pretty hot, pre-tin my pins very very lightly, just want enough so the board can grab it. I use a cleaning string to make sure my holes are pre-tinned but still open. Then I slide it in, set it flush and hold it however I need too. I slather the area with copious amounts of resolder flux and run my iron across the pins to secure them to the board. I use an acid less stuff, so I don't have to clean up, but I do wipe it with a rag. The extra amount I use helps to dissipate any heat the other components might experience and the part I'm replacing itself. I could probably get away with way less, but my flux usually goes bad before I ever use it all, so I'm not really worried. lol
 




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