Hakko FR-301 desoldering gun not working as good as it used to

[Pcmaker]

I bought it a year ago and rarely use it to replace the switches on my computer mouse. It heats up and there's suction. I cleaned the tip with the poker tool and replaced the filter and same deal. Not sure what I'm doing wrong. I max the heat setting and stay on the pin for quite a few seconds and it only gets some of it. I can still see solder inside the pin hole and I can't remove the switch. I have to use a copper wick to grab the remaining solder.

It used to take 1 or 2 seconds and it would suck up pretty much all the solder, even on a lower heat setting. 

What works, though, is if I put flux first on the pin then use the desoldering gun. The thing is, I didn't have to do this before. I just put the pin in the nozzle and press the trigger and I'm done.

There's nothing wrong with the temp since I can feel the immense heat when it's on.

[Bud]

You should treat the desoldering tool tip same as if it was a soldering gun- clean with sponge and tin with solder and keep it that way throighout a job and right before turning it off after the job. My guess is the tip has oxidized to the extent there is poor heat transfer from the tip. You should not crank up the heat all the way up, just set it good enough for a specific job. Overheating will wear the tip prematurely.

[floobydust]

It sounds like poor heat transfer from the tip to the part. I keep my desoldering tip tinned or else it goes black and then does poorly heating up things.  Your technique might be too fast- put the tip on the pad, squarely on it not crooked, wait a couple seconds for heat to flow to the top side, then hit the vacuum. If that doesn't pull all the solder, ADD fresh solder to the pad, and re-do but wait longer for the heat to flow to the other side of the board. Careful not to overheat the pad, sometimes leave it to cool down.
Also, lead-free rework can clog things so use the poker when it's hot and push out any slag at the back. You might have low suction.

Best is to practice or troubleshoot a desoldering problem on junk boards.

[Pcmaker]

It works great if I add flux to the joint, but I didn't have to do this before

[rsjsouza]

It works great if I add flux to the joint, but I didn't have to do this before

Precisely as the others have mentioned. Heat transfer has become poor and the flux improves the scenario.

Perhaps consider getting a new tip? Tips are consumables, although good quality ones can last quite a long time (the original tip that came with my ~10 year old FX888 is still in good shape).

[0culus]

I'm going to offer another possibility....it's still plugged. Mine started doing something similar despite careful tip care and regular cleaning with the poker tool it comes with, but I discovered there was still a gigantic glob of solder stuck just where the poker couldn't get it from the front (remove the canister to see it). After getting that off, it worked *much* better and I realized how much the vacuum pump had been struggling. Also make sure to change the filter occasionally. It gets blasted by the hot solder and flux fumes, and it's required to protect the vacuum pump from damage. Now I am much more careful to clean it from the back side too. Oh and make sure to also clean the metal piece that sits in the canister as well.