New Weller D550, and there is a screw missing from the housing near the heating tip, and the other two housing screws are stripped. When I plug it in and try to use it, the lights flicker and it doesn't heat up. It was made in Mexico. Should I replace the screws with a slightly larger self tapping screw, or just return it?

The manual is available here: http://www.cooperhandtools.com/onlinecatalog/Operating_Instructions/D550-8200_Gun_Instructions.pdf . This is the manual for the Weller 8200 and the D550.

I hope this helps.

Cindy Wells

Just loosen the screw in the barrel near the tip, then rotate while pulling the tip out. It shouldn't be necessary to remove the tip unless it requires replacement. Hope this helps!

HERE their is a collar that slips over the tip holder theirs screws that go through the holes on the tips that secure the melting tip hope this helps

It is supposed to produce heat there, it's the place where catalytic combustion takes place. If the tip doesn't heat up enough, it means that either the tip is not screwed properly into the housing, or there's not enough gas pressure. The catalytic mesh should be orange in color when heated properly.
Too low gas pressure may be a result of many things, like a malfunctioning valve (regulator and/or on/off),or clogging of the ceramic pressure reductor due to poor quality gas used, with high heavy fraction content.

Hi, I'm not sure the tip is defective. Check that the tip is screwed in tight. If it is not good and tight the tip will not get a good heat transfer from the solder wand. Hope this helps. If the wand will heat then the tip should.

It probably isn't; the tightness of the nuts is critical since any resistance at that point will reduce the current flow and cause the tip to heat slowly or not at all. The element will also oxidize at its connection point too which also causes a loss of current over time.

I cannot see by the picture if you have one or two light bulb model, but if you have the 2 bulb, then you must know that these bulbs are in series so they both must be good and they have to be 1,5 volt bulbs each or you will get a very dull light. If it is a single bulb, then you need to check the screw-in socket and check the bulb with an ohm meter or continuity tester. iF ALL TESTS OK, THEN THE PROBLEM IS INTERNAL AND YOU WILL HAVE TO OPEN THE GUN OR JUST FORGET IT. GOODLUCK, MACGIVOR.

are you sure you bought the H.D. tip this is the big gun

Heat gun tips often get bad electrical connection where the nuts tighten to the tip ends. Remove the tip, clean the ends, re-install the tip, making sure the nuts TIGHTEN onto the tip ends. Your problem is common and always caused by a poor connection at the tip ends/nuts.