I agree.Plus it looks like the solder hasn't adhered to the pins very well.I would apply flux and resolder at the very least.The Pace solder course stressed "flux is your friend",use it on all your connections.As well the gate resistor joint visible in the pic looks like a cold joint.That said you should probably flux and resolder all joints on the board,only takes a couple of minutes.Clean with isopropyl after and see if the joints are nice and shiny and wicked onto the component leads nicely.
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The black coloration is from today when trying to reflow the solder, but point taken.
The purple hue on the back and source lead of the mosfet was already there.
Does that indicate failure on the way or not? Logical thing to do is replace both mosfets, but this could be a learning situation.
Does the color change on the back indicate overheating?
thanks,
Vince
Clean all the black with a toothbrush(not yours,the wifes 🙂 ) and alcohol,flux and resolder.I wasn't commenting on the gate lead purpleish coloration (didn't notice that),I was commenting on the lumpy, graininess, dullness of the joint.The black is probably mostly overheated solder flux but after cleaning you will probably see the board is kind of yellow there.
Ok, will clean and reflow the solder on the mosfet.
I had been using a Weller non-lead solder which was harder to work with, even with fine gauge solder.
Switched to a Vellemens non-lead solder recently and it flows much better than the Weller solder.
Joints have a more smooth, even face that doesn't bubble out.
I get a headache each time I solder and I use fume extractor. Building gear is a labor of love that's wearing me out. 🙁
Velleman Lead Free Solder Dispenser Pack - Micro Center
I had been using a Weller non-lead solder which was harder to work with, even with fine gauge solder.
Switched to a Vellemens non-lead solder recently and it flows much better than the Weller solder.
Joints have a more smooth, even face that doesn't bubble out.
I get a headache each time I solder and I use fume extractor. Building gear is a labor of love that's wearing me out. 🙁
Velleman Lead Free Solder Dispenser Pack - Micro Center
Less toxic. I don't know. You see my last post?
The real problem for me is the rosin.
Im thinking of buying a roll of WBT.
I'm just looking for something that melts at lower temp and wets well. Don't care how I get there now.
The real problem for me is the rosin.
Im thinking of buying a roll of WBT.
I'm just looking for something that melts at lower temp and wets well. Don't care how I get there now.
I don't use solder with any type of flux core. My preference is a No Clean flux pen and 63/37 solid solder.
63/37 flux core solder is the best as far as i'm concerned and I repaired electronic eqpt. for a lot of years,however you need additional flux to get the best joint possible.As I said before the Pace high reliability solder course I took as well as the SMT solder course I took all said 63/37.Pace company mfr's. solder equipment. In addition the instructor said they repaired Israely Air Force circuit boards that had been shot in combat so I assumed they knew what they were doing.
I would never use lead-free solder. It's difficult to work with and it destroys soldering iron tips quickly.
Anyone know if Kester 331 63/37 (low smoke) is OK?
Kester 331 Organic Core Solder 63/37 .031" 1 lb. Spool
Kester 331 Organic Core Solder 63/37 .031" 1 lb. Spool
I don't care for it either. It's the higher temperature that takes out the tips,
and it's harder to re-work, making it inconvenient for DIY.
Mr Pass and ZM, you guys ever see a mosfet go purplish like in photos 2 pages back? Is that from over-heating during operation? Do you think there's damage to the mosfet?
thanks.
thanks.
if mosfet is still alive , blame solder fumes , grease , whatever
if it's Dodo , don't think
think next time while mounting one - no burrs , proper pad , proper torque , big washer ,split washer
and yes - proper old fashioned solder (lead) and properly big solder tip
tiny ones are for sissies 🙂
if it's Dodo , don't think
think next time while mounting one - no burrs , proper pad , proper torque , big washer ,split washer
and yes - proper old fashioned solder (lead) and properly big solder tip
tiny ones are for sissies 🙂
It was the p-ch mosfet or the trace/pad on the gate.
I probably cooked it on first build. Gate pad lifted on removal. Put in a wire from gate resistor to the gate. Biased up fine. It's complete silent now.
Thanks
Vince
I probably cooked it on first build. Gate pad lifted on removal. Put in a wire from gate resistor to the gate. Biased up fine. It's complete silent now.
Thanks
Vince
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