Model #7833 Battery Repair / Replacement Cordless Soldering Iron


Model 7800, 7840 cordless soldering iron battery replacement P/N 7833 battery. Please only try to replace the battery on your Model #7800 if you are experienced with using a soldering iron.

The Fast Charge Cordless Soldering Iron (Model #7800 / 7840) uses a bi-metal snap disc thermostat to sense the battery temperature during the charging cycle. It’s that odd mini hockey puck looking thing with the red plunger on the tip end of the battery. The plunger fully extends, meaning the battery is at maximum temperature signaling it’s fully charged. There needs to be a small air gap (.010 roughly) between the end of the plunger and the white arm. The white arm is the slide that activates the quick charge mode on the side of the iron. The air gap needs to be available, otherwise the plunger may not fully extend keeping the soldering iron in fast charge mode. If the air gap is too big the fast charge mode may not become activated and you just paid a bunch more money for our basic Quick Charge Pro soldering iron Model #7700.

Options to Replacing the Battery

Most of our customers are really smart humans…after all they bought from us and they know how to fix stuff. Customers have several options when replacing this battery. First option is to just send it in to us and let us go through the tool, then test and repair anything else the iron or charger may need. The other is to do it yourself which we all like to try at least twice. Just be aware of this issue and that is why we pulled it from the web site. We still make it and we still will sell it. We just like to talk to you sometimes and let you know the gotcha’s in putting this one in.

If you have any questions contact us today!