Here at Hackerfarm, we use 18650 rechargeable lithium ion batteries for just about everything. We …
This is a new series we’ll be doing on the Hackerfarm website. Here at Hackerfarm, we’re constantly taking things apart to figure out how they work and how to fix them. We don’t have a lot of money so one of the techniques we employ is to buy broken items from Yahoo Auctions for super cheap and try to fix them. We do this for power tools, Dyson vacuum cleaners, and many other products that cost too much to afford new, but can be bought cheap as a “junk” device and repaired.
This Ryobi impact driver was one of the items we bought about four years ago to bolster our impact driver collection. We have to do a lot of carpentry out here to fix floors, houses, barns, and general renovation so impact drivers get a lot of usage. This particular one stopped working a while ago and we have some big jobs coming up to renovate a beautiful old house and barn. I wanted to get all of our impact drivers up and running with fresh batteries so we could get more people to help out with things. This is a Japan-only Ryobi model BID-1220. They were about 30,000 yen new but we picked a pair of them up without batteries for around 3,000 yen.
Here’s a shot of the pair of Ryobi impact drivers we picked up circa 2015 along with some drills. We standardized on this Ryobi series because they all used the same batteries.
For batteries, we generally buy old battery packs, take them apart, and install fresh 18650 rechargeable batteries inside them. You can actually solder 18650s if you’re careful, so replacing them mainly consists of re-soldering the old wires on to new batteries. The reason we like old battery packs is that the circuitry inside is the most valuable part and handles the charge control and communicating with the chargers. The new 18650 batteries are about $1/cell in Shenzhen and we usually have a bunch of them lying around hackerfarm. We’ll do a battery teardown and replace in a later article.
For this repair job, the Ryobi had stopped working, even with fresh batteries inside. I was worried that the motor burned out but since we didn’t use it for anything heavy duty recently, I didn’t think that was the case. It had been left on a shelf for a while because we haven’t done a floor since last year. Perhaps the humidity got to it. Anyways, it’s always best to take something apart to understand it.
Here is the problem impact driver. It’s sporting a freshly charged battery. You may notice that the battery isn’t a factory model. We also buy cheapy NiMH batteries from China when they’re available for the power tools we have. At this point the impact driver didn’t respond to pressing on the trigger.
I pulled out all the screws so that I could take apart the handle. There is also a screw hidden in the base that’s recessed deeply inside a hole there.
Before I could separate the handle, I found I had to remove the head first. There were four screws holding it in place. Once they came out, you could easily remove the head. This held the turning mechanism, gear reduction, and the weighted “impact hammer” that makes it so powerful. There was also a lot of grease on the gears. I can imagine that if the seal ever becomes bad, sawdust mixed with grease could cause a lot of problems for the drills.
Once the head was removed, I used a screwdriver to pry open the two halves of the impact driver. There was a lot of dust and debris inside. The dust was a bit wet like a paste. Possibly, there was residual grease that sawdust mixed with. I had to blow on the trigger mechanism and area around it to clean out the debris.
I plugged the battery directly into the trigger mechanism and measured the voltage. I had to be careful since plugging it in backwards could potentially damage the driver. On the other hand, it might just make the motor go in reverse. Ha ha ha.
The battery voltage was okay but I wasn’t seeing any voltage on the wiring at the trigger. This meant that there was a bad connection either on the battery contacts or on the trigger contacts. I continued blowing and cleaning the battery contacts and trigger contacts with the wires. I also scraped the battery contacts to remove oxidation that had built up on it.
Finally I got it to work. The problem was oxidation and debris on the battery contacts. After scraping it a bit, I could get the motor to turn.
Closing up the impact driver was pretty straightforward. It’s almost all motor and just has the trigger switch and contacts to the battery. I did need to be careful with putting the wiring back into the wire guides to make sure it would close up properly though.
Impact driver as good as new. Luckily, this was an easy fix.
Yay! We could salvage the tool which will be a huge help. We will be rebuilding a bunch of floors soon on a house that Jacinta and I will be moving into. That’s part of a different story though 🙂