Garrick's RC boat burned out on it's first real use. The boat wasn't junk, I just got unlucky with a faulty part, and didn't want to return it as I'd bought it weeks before at an insanely discounted price.
I cut a small hatch into the top to access the RX circuit, and determined it had blown at least one power-transistor (...it had visually exploded...later dad identified it as a mosfet), and possibly more components. Unfortunately the part numbers had no real life counterparts so replacements would be a best-guess scenario. Adding up the electronic parts totaled an estimated ~$25, and a low probability of success. This isn't the cost of a replacement circuit...it's the cost of components that have to be re-soldered with the hope that's all it's gonna take.
Given the cost vs reward was low, I decided to cut the whole top off of the boat, and simply replace everything with proper RC equipment for big boys toys. The price wouldn't be vastly different, yet the results would be superior, including fully proportional controls and modularity in parts for replacement.
The boat has a whacky dive feature and goes fully underwater for brief dips. This meant the top is glued on, and had zero chance of removal without cutting hatches. A sloppy cut-out with a dremel gained access to the RX board. I then made a much cleaner cut around the entire boat with a hack-saw to get access to, and remove all the interior components.
Upon testing the motor I found it was actually the source of the problem. It had a serious short, and while it certainly ran, it cooked hot in seconds and undoubtedly was the cause of the circuit burnout. This meant I needed a new motor. :( Unfortunately I'd already ordered a new brushed motor controller online. Had I known the motor was the problem, I would have bought a regular 3-phase brushless hobby motor and controller which would have had more power, and been a few bucks cheaper.
I didn't want to spend more money on the boat, so I dug through my bits and dug out an old cordless drill motor (18v unfortunately) with it's gearbox gears, and a prehistoric 12v brushed hobby motor which I'd somehow held onto since I was in my 20's. Unfortunately I now had to deal with a variety of mismatching shaft diameters, gears, and the original boat gearbox.
The boat is in the toy-category, but it was just pricey enough to have an off-the-shelf hobby gearbox that had mounting holes for two of the most commonly used ~12V motors for the last few decades. This meant my kludge motors were in for a much higher chance of success, and way less work for me to mount correctly.
27mm original motor left, with 13mm spacer-colar. 35mm hobby motor right with the same 13mm colar.
The brushed motor driver arrived in the mail. A shame they're so big compared to regular multi-phase ESC's.
I need to mount this 2mm pinion gear onto a 3mm shaft.
The drill gears were 3mm, but their teeth were ever so slightly different. It was close enough that I could have run with it, but since I had the original pinion gear in my hand, I decided to resize the hole.
...and vomit, my drill bit quality is ultra low and the hole is significantly too large. I should have done a test drill first. I'm too used to nice expensive bits at work drilling out holes the size they're supposed to be.
Given the sloppy drill-out and no grub-screw opportunities anyway, I jammed a safety pin wire into the shaft-key and epoxied the thing on.
Mounting some servos, and adding some linkages as needed. Kludge-o-rama.
My replacement motor shaft isn't long enough to engage the pinion gear adequately. This is a problem.
...however there are floating nylon bushings in here that are about the same size as the offset I need to correct the problem...
Incredibly, the notching in the drive shaft is significantly longer than the offset I need. This means I can slide the drive-gear by one-bushings-space down, and still keep everything engaged.
Now I can put the nylon bushing onto the opposite side of the drivegear with it's sister, and still maintain correct spacing across the width of the gearbox without anything moving around. Megga-win.
I need new mounting screws for the replacement motor. Here's a pile of computer screws I prepared earlier which live in my desk...thread-match-sweepstakes.
...but if you look closely, you'll see I'm making a mistake here...
Yeah, it's mounted now, and the teeth engage nicely.
But can you see the mistake??
Argh!! I was supposed to mount this motor, not that one!!! This one has the correct pinion gear on it!!
Not kidding, I dismantled, and re-mounted the WRONG MOTOR, THREE TIMES IN A ROW !!! It was really late. :(
Testing all systems. RX, battery and motor controller not mounted yet.
I cut some plastic strips from an ice cream container to glue in as support ledges when regluing in the top deck of the boat.
RC gear all velcroed in. Wires tied up.
Silicone seal the whole top back on.
The 35mm drum motor doesn't actually fit inside the old hull... Some heat-gun work and hot-glue fixed the problem though. :D
Some experimental heat-gun work made this hatch shrink at the corners a little.
Overall this was a massive kludge that should have been a lot easier, isn't re-painted because paint... yet performance is vastly superior to the original toy. Can't wait for Garrick to chew through a battery's worth of drive-time down at the lake later this week.
