After being summoned by a distressed 11 year old who accidentally broke the antenna on his dad's vintage R/C car controller, I accepted the challenge of repairing it without making it obvious that had been repaired. The offending controller displayed above.
Step 1: Step 1: Initial Disassembly.
Bog standard philips screws holding the molded plastic shell together. Ah, the smell of aged silicon and leaky electrolytic capacitors...
Gladly the antenna had snapped at the largest diameter of the telescoping antenna assembly, which made it much easier to prepare both ends for repair.
I started by cleaning the antenna assembly with 99% Isopropyl Alcohol. Then I used a fiberglass pen to scratch micro-abrasions on both sides of the break in the antenna assembly. This is to provide microscopic molecular channels for the solder to flow into on each side of the polished chromed-nickel surface of the antenna material. Smooth, shiny surfaces need the extra abrasion preparation in order to insure the solder will bond correctly with the base material.
Step 2: Step 2: Create Antenna Splint.
After measuring the inner diameter of the broken antenna, I determined I could twist a bare metal coat hanger together to achieve the proper circumference. I used locking pliers to twist the coat hanger ends together, then snipped off an approximately 2 inch portion of the twisted wire with heavy duty wire cutters.
I confirmed the cut piece fit into the antenna assembly.
Then I applied rosin flux (I use SRA Tacky Flux) to the twisted wire, heated it up with a small torch, and 'filled' the gaps in the twist with 98% silver solder, for max conductivity in the splint.
Step 3: Step 3: Solder the Things
I removed the antenna base from the controller, inserted the splint, and attached the other side of the the antenna assembly.
Fluxed it, then soldered it. Make sure the ends are firmly together, and that solder has flowed into the joint, and over the splint.
When done, clean the flux off with alcohol, and go over it a bit with a micro-file in order to smooth out the solder joint visually.
Step 4: Step 4: Test and Reassemble, and Test Again.
Tested that the assembly could still extend and retract as before, then reattached to controller.
Assembled controller, added batteries, and tested for 'on' state. Once 'on' achieved then tested remote controls to Vehicle. All channels worked with no palpable degradation in signal strength .
Step 5: Step 5: Success!!!
Repair barely visible. Antenna is now structurally stronger than before, with little to none in the way of loss of signal.
11 yr old Todos:
Continue terror campaign against cats with ancient R/C car. Results effective, if not entertaining so far.
Continue to attach things exceeding the maximum allowable weight of the chassis. Mixed results.
Remind the adults that I'm to be a jerk-teenager soon, whilst expecting them to fix my things for free. :)