Etech33

I found this schematic on "vintagemachinery.org". It doesn't show terminal "B" like you are wanting to see. The FURNAS model # doesn't match the part in the list for MAGNETIC with low voltage control, but yours is probably made a little earlier model as in AJ71 vs BJ71. In any event, it is still 24 VAC on the secondary for low voltage control. The wires look like they have been replaced with newer ones at one time which is not a bad thing as long as it was wired correctly. I can't see all the detail in the picture, but you might be able to use this schematic to help you. You also need to make sure that you have the correct source power to match the way this machine is set up to run. As you can see in the schematic, the low voltage (24VAC) transformer is wired to L1 & L2. The primary is labeled 240/480 depending on how you strap it, you still get 24 VAC out. The 24 VAC (Hot) is then wired to one side of the stop switch which is normally closed which is electrically tied to one side of the normally open Start switch. The return off the 24VAC transformer X2 is wired to the current protection normally closed IOL contacts to the magnetic starter's coil. With power disconnected, you should be chase the wiring to see where 24VAC return goes to and where the 24VAC hot goes to validate that it is wired correctly. I notice too, that the wires have labels on them which if they match to the numbers on the magnetic starter, then it may be wired right. You also have a fuse on the secondary that can be blown. Make sure you terminals are tight and where they are crimped that the wire is in good shape, not black or corroded. I'm not sure what symptoms you have with it. The switch cover if removable, it may have a small schematic label on the inside. Hope this is some help or a start.

In my previous post, circuit board # 270264001 fixed the variable speed problem. I inspected the bad board that I had pulled out and found that the MOSFET was short about 10 ohms between Drain and Source, pin 2 and 3. In diode check mode with a multimeter, with the negative lead on pin 2 and the positive lead on pin 3, you should read about .589 ohms and infinite with the leads in reverse. I ordered a couple of MOSFET's PN# IRFZ44N from Mouser electronics with one being a spare. A $ 1.12 ea. I bolted on a small piece of aluminum fin to the tab to help dissipate heat and replaced the component on the board, then disassembled the caulking gun to replace my new board with the one I just repaired for an actual test. The repaired board worked, so I'm leaving it in. Now I have a spare new board and a spare MOSFET. Browsing the Net just didn't show much information about this model. The caulking gun and chord less circular saw are the only 2 power tools I have from RIGID. Both have come in handy. I paid a lot for this caulking gun at the time, so felt the need to repair it. Hopefully, if there is anybody out there that is still using this tool and they have the same failure, this info can get them back to a variable speed function with the exact fix for the cost of the part and ground shipping, approx. $12.00.

Carl, I found this on through images from vintagemachinery.org. Good luck on the parts. Check out your local wood turners clubs in your area for some one who may have knowledge of older lathes. Another resource could be "WoodCraft". Some of the staff are usually fairly knowledgeable. ETech33

The last Post I found regarding the R8804 caulking gun was in 2012. There wasn't really a specific symptom associated with repair of cold solder joints to help me compare with the bug that I had with my caulking gun, however, the post was appreciated. That is an excellent way to fix some issues on circuit card assemblies with regards to components, but especially with wires and connectors. I'm not sure if anyone still owns this cordless tool, but hopefully this information will be of some benefit to someone. I was caulking the T111 grooves on a shed I built in 2000 and repainting it. As I went through a few tubes of Quad caulk, I noticed that the speed could no longer be adjusted to a slower speed. It would work only at full speed which made it a little harder to control the flow. There are only 2 circuit card assemblies. The one that fixed the problem was from the Rigid R8804 diagram: KEY 16 P/N 270264001 CIRCUIT BOARD ASSEMBLY You can get it from eReplacementParts for approximately $25.00