- RADIOSOL step by step tutorial: Build the RDA5807 FM radio kit from bare PCB to working radio
- Core rule: Solder low-profile parts first (chips, resistors), tall parts last (display, switches)
- Polarity matters: Electrolytic capacitors and LEDs follow the long-lead-is-positive rule
- Power safety: Never use USB power and batteries at the same time
- Final test: A correctly assembled radio powers on and auto-searches for stations
Kit Overview and Preparation
This RADIOSOL step by step tutorial walks you through every stage of building the RDA5807 FM radio soldering kit. The project transforms a set of through-hole components into a fully functional FM radio with a four-digit digital tube display, station memory, and adjustable volume. It is suitable for both seasoned hobbyists and beginners diving into electronics.
Video Highlights:
- Full assembly of the RADIOSOL RDA5807 kit from unboxing to first power-on
- Correct orientation techniques for the radio module, IC sockets, and display
- Battery contact wiring and speaker installation inside the case
- Final testing and troubleshooting advice for cold solder joints
Before soldering anything, sort your components and confirm you have the items listed below. Working from a organized tray dramatically reduces mix-ups between similar-looking resistors.
| Component | Quantity | Board Position | Key Identification |
|---|---|---|---|
| AMS1117 voltage regulator | 1 | Top pad | SMD chip, solder pad first |
| RDA5807 radio module | 1 | Module pads | Square part down, cylinder up |
| 10k ohm resistor | 1 | R16 | Brown/black/black/red/brown bands |
| 1k ohm resistors | 5 | R2-R6 | Note R6 sits apart, near USB |
| 510 ohm resistors | 8 | R7-R14 | Green/brown/black/black/brown |
| 1uF electrolytic capacitor | 1 | C3 | Long lead = positive |
| 100uF electrolytic capacitors | 4 | C4, C5, C7, C8 | C8 is higher on the board |
| 104 ceramic capacitors | 4 | C1, C2, C6, C9 | Marked "104" = 100nF |
| 200k potentiometer | 1 | R1 | Volume control |
| IC sockets | 1 + 1 | U9 (8-pin), U2 (16-pin) | Notch aligned to silkscreen |
| LED | 1 | D1 | Long lead = positive |
| Toggle switch | 1 | P5 | 5 solder points |
| Audio socket | 1 | U4 | 5 solder points |
| Tact switches | 4 | S1-S4 | Press-fit, then solder |
| 4-digit display | 1 | Display pads | Match decimal points |
| TDA2822 + STC8G chips | 1 + 1 | Into sockets | Notch to notch |
Always solder in this order: chips and resistors first, then capacitors and sockets, then switches, display, and antenna last. Installing tall components early blocks access to nearby pads and leads to poor joints.
RADIOSOL Step by Step Tutorial: Board Assembly
The core of this RADIOSOL step by step tutorial is the board assembly itself. Use the tacking technique throughout: apply a small amount of solder to one pad, position the part while the solder is molten, then solder the remaining pins. This keeps every component aligned.
Mount the Voltage Regulator and Radio Module
Solder one pad of the AMS1117 position, position the chip, then finish the remaining pins. For the RDA5807 module, check the PCB silkscreen: the square component faces downward and the cylindrical component faces upward. Tack one connection, verify alignment, then complete the rest.
Install the USB Socket
Seat the USB socket at the DC power position. Solder the upper side first to hold it securely, then flip the PCB and solder the remaining pins from the back.
Solder All Resistors
Bend both leads of each resistor, insert through the holes, solder from the back, and trim excess. Install the single 10k at R16, the five 1k units at R2 through R6 (remember R6 is farther left near the USB connector), and the eight 510-ohm units at R7 through R14.
Add Capacitors, Sockets, LED, and Switches
Install the 1uF electrolytic at C3 with the long lead in the plus-marked hole, then the four 104 ceramics at C1, C2, C6, and C9. Seat the 8-pin socket at U9 and the 16-pin socket at U2 with their notches matching the silkscreen. Insert the LED at D1 (long lead positive), the toggle switch at P5 (five points), and the audio socket at U4 (five points).
Finish with Tall Components
Install the 200k potentiometer at R1 and the four 100uF electrolytics at C4, C5, C7, and C8, honoring polarity. Mount the four-digit display by matching its decimal points to the PCB markings, add the four tact switches at S1-S4, and solder the antenna vertically.
Insert the ICs
Straighten the pins of the TDA2822 power amp and STC8G controller so they are perpendicular to the chip body, then insert each into its socket with the chip notch facing the socket notch.
Reversed electrolytic capacitors or a reversed LED will prevent the radio from working correctly and can damage parts. Double-check every plus-symbol marking before soldering, because desoldering a through-hole capacitor is far more work than verifying orientation.
Case Assembly and Wiring
With the board complete, shift attention to the enclosure. The battery contacts and speaker wiring are the most detail-oriented part of this build.
Battery Contacts
- Spring contacts = negative terminals
- Flat contacts = positive terminals
- Mounting tabs face downward
- Bend tabs on the two long contacts to secure
Wiring Color Code
- Red wire = positive terminals
- Black wire = negative terminals
- Route wires through the grooves beside the contacts
- Pre-tin pads and contacts before attaching wires
Solder a red and black wire pair to the short battery contacts, then attach the other ends to the BAT pads on the PCB, matching red to positive and black to negative. For the speaker, solder the second red/black pair to the speaker terminals, then connect the free ends to U8 on the board, again matching polarity. Seat the speaker in its mounting slot, align the circuit board with the case slots, and press it into position.
| Wiring Task | Red Wire | Black Wire |
|---|---|---|
| Battery contacts | Positive (flat) contact | Negative (spring) contact |
| PCB BAT pads | Positive BAT pad | Negative BAT pad |
| Speaker | Positive terminal | Negative terminal |
| Board connector U8 | Positive pin | Negative pin |
Install three AAA batteries (negative ends against the springs) or connect a USB cable, adjust the potentiometer for volume, and confirm the radio powers on and searches for stations before screwing on the protective cover.
Power Options and Safety Rules
The kit supports two power sources, but they are not interchangeable during operation. Follow the rules below to avoid damaging the regulator circuit.
| Power Source | Requirements | Notes |
|---|---|---|
| 3x AAA batteries | Negative terminal to spring contact | Reinstall after assembly, then fit cover |
| USB cable | Standard USB power source | Use when batteries unavailable |
| Both together | Never | Do not use USB and batteries simultaneously |
Never power the radio from USB and batteries at the same time. If the radio fails to work, first try fresh batteries or a different USB source before suspecting the soldering.
Build Checklist and Troubleshooting
Assembly Milestones:
- AMS1117 regulator and RDA5807 module soldered with correct orientation
- All 14 resistors installed and leads trimmed
- IC socket notches matched to silkscreen at U9 and U2
- Display decimal points aligned before soldering
- Battery contacts wired red-to-positive, black-to-negative
- Radio powers on and auto-searches for stations
If the finished radio does not work properly, work through the failures in order of likelihood:
| Symptom | Likely Cause | Fix |
|---|---|---|
| No power on | Weak batteries or bad USB source | Try fresh batteries or another USB supply |
| Powers on, no sound | Speaker wiring reversed or cold joint | Inspect U8 connections and speaker terminals |
| No display | Display orientation wrong | Verify decimal point alignment |
| Intermittent behavior | Cold solder joints | Reinspect all joints and reflow dull ones |
| Buttons unresponsive | Tact switch not fully soldered | Reflow all four switch positions |
When everything is assembled and soldered correctly, the radio powers on and automatically begins searching for FM stations. That first auto-scan is your confirmation that the build is complete.
FAQ
Q: How long does the RADIOSOL step by step tutorial build take?
Most builders complete the RDA5807 kit in two to four hours depending on soldering experience. Beginners should budget extra time for inspecting joints and double-checking component orientation before each soldering step.
Q: Where does the R6 resistor go?
R6 is one of the five 1k ohm resistors but it is not located next to R2 through R5. It sits farther to the left on the PCB, near the USB connector. Installing it with the other four without checking position is a common mistake.
Q: Can I use USB power instead of batteries?
Yes. If batteries are not available, power the radio through a USB cable at the DC power socket. However, never use USB power and batteries at the same time, as this can damage the power circuit.
Q: What should I check if the radio does not turn on?
First try a new set of batteries or a different USB power source. If the problem continues, inspect every solder joint carefully, since one or more connections may not be making proper contact.