How to unsolder transistor

[Rockguy]

Re: How to unsolder transistor

I should have known that since I put one lead of my meter on the tab when testing it Duh

[Rockguy]

Re: How to unsolder transistor

I think you'll be fine. Trace those connections then verify with your meter they are still good then flow some solder on the large pad and see what you've got.

Where the solder remains, I have continuity with the other transistor tabs. Obviously where the copper is torn out, there is nothing. There is no damage where the legs were.

Is the goal to try and flow new solder attaching to the old and filling the damaged area? Do I need to get a copper sheet and epoxy it in there?

[stj]

Re: How to unsolder transistor

if the tabs are all connected, you could solder a stiff copper wire across a few.
your really just trying to physically hold it down.

[mmartell]

Re: How to unsolder transistor

Did you test the fet for short after you pulled it ? How did you know this one was short and not another one that is in parallel ?

[Rockguy]

Re: How to unsolder transistor

Did you test the fet for short after you pulled it ? How did you know this one was short and not another one that is in parallel ?

Yes, I tested it out of circuit. With that FET missing, I briefly fired up the tv and it was working so I should be good when I put this new one in. I'm planning on messing with that today if nothing comes up. I was working too much the last couple of days.

[Rockguy]

Re: How to unsolder transistor

if the tabs are all connected, you could solder a stiff copper wire across a few.
your really just trying to physically hold it down.

That does seem like another option. Thank you for suggesting it. If flowing solder in there doesn't work as well, I can do that.

[Rockguy]

Re: How to unsolder transistor

That does seem like another option. Thank you for suggesting it. If flowing solder in there doesn't work as well, I can do that.

As I feared, the solder will not stick to the area where the solder and everything was torn out. I'm gonna have to go with another plan.

[SteveNielsen]

Re: How to unsolder transistor

Can't you get solder to take where the copper is still intact? It may be enough to do the job. As I said earlier my concern is heat sinking the transistor enough through it. I wouldn't glue copper onto the area unless using highly conductive glue (both electric and heat conductive), but you could try soldering a copper shim to it and then solder the transistor tab to the copper shim.

[Rockguy]

Re: How to unsolder transistor

Can't you get solder to take where the copper is still intact? It may be enough to do the job. As I said earlier my concern is heat sinking the transistor enough through it. I wouldn't glue copper onto the area unless using highly conductive glue (both electric and heat conductive), but you could try soldering a copper shim to it and then solder the transistor tab to the copper shim.

Yes, I can get solder to take where the old stuff is still there. Understood on the copper. I won't glue that in there. Your idea of soldering a copper shim sounds plausible. I got a tip from tom66 to possibly buy a tiny heatsink and attach to the top of the FET.

[stj]

Re: How to unsolder transistor

thick copper wire soldered across 3 tabs (the new one in the center) should conduct the heat better thansticking a heatsink to the resin body.

[Rockguy]

Re: How to unsolder transistor

thick copper wire soldered across 3 tabs (the new one in the center) should conduct the heat better thansticking a heatsink to the resin body.

That would be pretty easy too I think. What kind of wire would you suggest?

[stj]

Re: How to unsolder transistor

the thickest solid copper you can find.
got a bit of the stuff used to wire in cookers?

[Rockguy]

Re: How to unsolder transistor

the thickest solid copper you can find.
got a bit of the stuff used to wire in cookers?

Hmm no. I've got some house wire.