Weller WD1. At power on screen says "OFF". The 3 preset temperatures are still displayed. Tested with a working lead and soldering tip, OK.

Question edited for clarity.

Weller Tech Sheet WTCPR.pdf

University of California San Diego https://neurophysics.ucsd.edu > Manuals
Power Unit Size 4-7/16" x 7-3/8" x 3-5/8". Six (6) Foot, 3 Wire Power Cord. 4. *. SOLDERING PENCIL: Soldering Pencil Wattage 48 Watts. Tip Voltage To Ground ...
4 pages

Weller Tech Sheet

UserManual.wiki https://usermanual.wiki > Manual > WTCPRTec...
If magnastat switch checks good, check wiring for continuity. Re- fer to schematic. C. TC202/TC202D Power Unit Troubleshooting Guide. (No 24 VAC at Pin 1 ...

Vintage unit

https://www.google.com/search?q=Tc202+power+unit

..

You might want to check the iron itself with an induction power tester to see if it is getting any power to the tip. This type of tester doesn't require any dis-assembly just close proximity to energized circuits.

http://www.testequipmentdepot.com/weller/powerunits/wd1.htm

http://www.apexhandtools.com/brands/cf_files/download.cfm?type=literature&file=550517.pdf

Contact the manufactu http://www.weller-toolsus.com/

I believe it takes the LT S E R I E S tips for the W S P 8 0 Soldering Pencil.
http://www.digikey.com/Web%20Export/Supplier%20Content/Cooper_72/PDF/CooperWeller_Catalog550543.pdf?redirected=1
has a catalog with the part numbers for the different types of tips.

The problem is caused by the ceramic heating element built into the iron, it becomes intermittent over time and cannot be accessed.

Hello, does your solder iron --Weller- humming? Also, is the solder tips the right tips for you Weller woldering gun? Are the tips tightened on the end of the solder gun prongs?

Well, if it is humming there is internal short in the windings inside of the gun. Don't mess with. Recyle it by taking the copper, brass, aluminum, and other metal out. Now, if it is not humming.
Make sure you have right tips, make sure that the tip is tightened in the soldering gun prongs.

The working principal of these soldering guns is that they work on low voltage and very high current. The current is regulated to keep the tip from burning into. Just enough current to heat the tipe to a certain temperature.. It can shock you but there not enough voltage with current but it will hurt. and could burn you. Be careful and lots of luck...GB...stewbison

Hello, your Weller 8200 soldering gun is rated at 140 or 160/100 watts. While the junior was about 70 watts. Go to this web site for parts: www.e-sonic.com/aboutus/cat/S/soldering%206.pdf GB...stewbison

You need to adopt an on-off-on---- action to control maximum temperature. Try to keep the tip so that the solder flows properly, but the tip doesn't try to burn up. Hope this helps!

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.