This teardown concerns a compact Jelly Comb Bluetooth keyboard with an integrated touchpad, not every keyboard sold under the same name. The 2017 examination found tactile key switches, an eKT2101 QN32 capacitive-touch controller, a Beken BK3231Q Bluetooth microcontroller, an unlabeled lithium-ion battery, USB charging hardware, a printed antenna and several useful test pads. It is easy to open, but far less straightforward to repair or reprogram.
The original teardown was published by All About Circuits on May 30, 2017. The exact retail model number was not established, so these observations should not be generalized to every Jelly Comb keyboard.
What was disassembled?
The device is a roughly 20 cm QWERTY wireless keyboard with function buttons, an integrated touchpad, a USB charging connector and power/control buttons on the rear. Its compact enclosure combines five jobs: physical key input, capacitive pointing, Bluetooth HID communication, battery charging and power management.
That combination makes it a useful example of cost-focused consumer design. Most of the digital work is concentrated in one wireless microcontroller rather than split between a keyboard controller and a separate radio module.
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- Wide Compatibility Tips: 2.4G USB mode works with Windows 11/10/8/7/XP. Bluetooth mode supports Windows 11/10/8/7/XP, macOS 10.12+, iPadOS/iOS 13.0+, and Android 4.3+. Note: Bluetooth 4.0 or above is required; 2.4G USB mode is for Windows only
- Triple Device Connectivity: Switch seamlessly between three devices via USB-A, BT1, and BT2 channels. Ideal for multitaskers, students, and hybrid workers who use both Windows and Mac systems. Eliminates desk clutter and the need for multiple peripherals
- Dual OS Layout Ready: Designed with both Windows and Apple keyboard layouts, this combo works across Windows, macOS, iOS, and Android. Perfect for users who switch between laptops, tablets, and desktops frequently - no relearning required
- Type-C Fast Rechargeability: Built-in battery offers 200 hours of use and recharges fully in 3 hours. Auto-sleep and on/off switch extend battery life. Great for travelers, remote workers, and eco-conscious users who value convenience
- Slim & Durable Metal Build: At just 0.12” (keyboard) and 0.9” (mouse), this set is ultra-portable and space-saving. Made with stainless steel and premium materials, it resists wear and fits easily into bags for work, study, or cafe sessions
Opening the enclosure without damaging it
The original teardown found no visible external screws or obvious fasteners. The lower shell could be pried away with a small flat-head screwdriver. A plastic opening pick is safer for a repeat inspection because it is less likely to mar the case or short a component.
- Switch the keyboard off and unplug USB.
- Inspect the underside for seams, labels, feet or concealed clips.
- Work a plastic pick around the seam; do not lever against the battery.
- Photograph cable orientation and board positions before disconnecting anything.
- Remove the small PCB screws and release retaining tabs rather than forcing the board.
Easy access is only teardown accessibility. It does not mean the battery, radio SoC or charging circuit is service-friendly.
Battery and USB charging section
An unlabeled lithium-ion cell sits inside the case. The teardown author estimated approximately 3.7 V, about 1 Wh and roughly 330 mAh from the surrounding electronics. Those figures are estimates, not a printed rating or a measured capacity. The exact chemistry, protection circuit, charge current, temperature sensing and cycle life were not established.
Near the USB connector are three resistors, two capacitors and a six-pin surface-mount device marked HXN MH. USB charging is confirmed; the function and part number of HXN MH are not. It may be a lithium-ion charger with an integrated linear regulator, but no pinout, schematic or measurement in the teardown proves that identification.
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- 3 Devices Switch with A Single Clicking: This keyboard is able to connect to 3 devices at the same time. You can switch between 3 devices with a single key clicking.
- Functional Built-in Cradle: The smartphone or tablet can be placed in the cradle for better viewing and typing. The heavy duty keyboard allows you to type firmly even with the cellphone or tablet standing in the cradle.
- Broad Compatibility: Use with all four major operating systems supporting Bluetooth (iOS, Android, Mac OS and Windows), including Computer, Desktop, PC, Laptop / iPad Pro, iPad Air, iPad, iPad Min, iPhone, Smartphone / Android Tablets like Samsung Galaxy, Surface etc.
- 6-Month Battery Life: Rechargeable lithium battery with an industry-high capacity lasts for 6 months with single charge (based on 2 hours non-stop use per day).
- Package contents: Arteck Bluetooth Keyboard, USB-C charging cable, welcome guide, our 24-month warranty and friendly customer service.
For a battery replacement, match nominal cell voltage, physical dimensions, connector polarity, protection arrangements and any thermistor connection. Never bypass protection circuitry or choose a higher-capacity cell solely because it fits.
The keyboard is a tactile-switch matrix
Under the keycaps are many individual surface-mount tactile switches, not the rubber-dome membrane construction often assumed for inexpensive wireless keyboards. Pressing a key closes an electromechanical contact; the controller scans the switch network and turns the result into Bluetooth HID reports.
This arrangement provides distinct actuation and makes an individual failed switch theoretically replaceable. In practice, a substitute must match the switch footprint, height, travel and electrical behavior. A single dead key can come from a worn switch, contamination, a cracked solder joint or a broken local trace.
Diagnosing key failures
- One key: test the switch, inspect its solder joints and compare its matrix connections with a neighboring key.
- A row or group: suspect a matrix trace, connector or controller-side fault before blaming several switches independently.
- Replacement: confirm the exact mechanical and electrical footprint before desoldering.
How the touchpad senses a finger
The touch surface uses a diamond-pattern electrode array beneath a plastic overlay. The overlay can be peeled away to expose the conductive pattern; the apparent orange color in the teardown photographs was attributed to lighting or reflection, not a special copper-colored coating.
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- Connect in seconds: Fast, easy Bluetooth wireless technology simply connects without the need for a dongle or USB port
- Durable and reliable: Built for quality, K250 offers long-lasting keys, a spill-resistant design (2)
- Comfort is key: Deep-profile keys and an adjustable tilt-leg design make typing feel great
- Space-saving: with a compact layout that still includes number pad, arrow keys, and handy F-key shortcuts
- Made responsibly: Designed to last, K250 plastic parts are durably made with minimum 64% recycled plastic (3) to withstand everyday use
An eKT2101 QN32 touch controller measures capacitance changes as a finger moves across the electrodes. The source describes this off-the-shelf IC as containing an 8-bit RISC microcontroller with SPI and I²C interfaces. Nearby pads marked SCL and DATA suggest an I²C connection to the main controller, but the bus mode was inferred from labels and layout, not demonstrated with a logic analyzer.
Intermittent touch usually warrants checking contamination, moisture, the electrode layer, its connections and power stability before assuming the controller has failed.
The Beken BK3231Q is the central controller
The main wireless device is marked Beken BK3231Q. The teardown identifies an ARM968E-S processor core, 32 KB of RAM, 256 KB of flash ROM and peripherals including timers, PWM, watchdog, ADC, UART, I²C, SPI and GPIO.
In this architecture the BK3231Q can scan the keyboard, exchange data with the touch controller, manage buttons and LEDs, and provide the Bluetooth link. Integrating those functions reduces chip count, board area and assembly cost. It also creates a single major failure point: replacing the SoC requires donor hardware and suitable rework equipment, while firmware may be undocumented or locked.
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- 3 Devices Switch with A Single Clicking: This keyboard is able to connect to 3 devices at the same time. You can switch between 3 devices with a single key clicking.
- Ergonomic design: Stainless steel material gives heavy duty feeling, low-profile keys, full size keys, arrow keys, number pad, shortcuts offer quiet and comfortable typing.
- Broad Compatibility: Use with all four major operating systems supporting Bluetooth (iOS, Android, Mac OS and Windows), including Computer, Desktop, PC, Laptop / iPad Pro, iPad Air, iPad, iPad Min, iPhone, Smartphone / Android Tablets like Samsung Galaxy, Surface etc.
- 6-Month Battery Life: Rechargeable lithium battery with an industry-high capacity lasts for 6 months with single charge (based on 2 hours non-stop use per day).
- Package contents: Arteck Stainless Bluetooth Keyboard, USB charging cable, welcome guide, our 24-month warranty and friendly customer service.
The teardown does not establish a precise Bluetooth version, radio mode, HID firmware implementation or pairing-security scheme, so none of those should be inferred from the chip marking alone.
Printed antenna and RF layout
A PCB antenna is located near the Bluetooth circuitry. A printed antenna avoids a separate cable and is inexpensive to assemble, but its performance depends on board ground geometry, clearance, enclosure materials, battery placement and nearby mechanical parts.
Do not treat it like a wire that can be lengthened or relocated arbitrarily. Added foil, metal screws, shielding, wiring or a changed case can detune the antenna and reduce range. Damage to the antenna trace is consequently difficult to repair without RF measurements.
Debug pads and reverse-engineering opportunities
Pads marked RX1 and TX1 sit near the BK3231Q. They may be UART or other debug connections; the teardown did not demonstrate a live console, AT-command interface, firmware readout or custom-firmware installation. Another unpopulated position is marked J4, but its purpose is unresolved.
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- iPad Keyboard with Built-In Stand for Tablets -- Turn your desk into a more efficient iPad workstation with this iPad keyboard’s integrated holder. The 14.4-inch long, 0.43-inch wide slot supports phones and up to a 12.9-inch iPad or tablet in horizontal view, making typing, browsing, online classes, and light work more comfortable. For a more secure fit, thicker protective cases may need to be removed.
- Multi-Device Keyboard & Mouse for Multi-OS Compatibility -- Compatible with iPhone, iPad, Mac, Android, Windows, Samsung tablets/smartphones, PCs and more, including iPad Pro/Air/Mini, MacBook Pro/Air and Surface Pro. It enables fast 2-device channel switching without interference or disconnection, automatically recognizing device systems and mapping keys, ideal for busy female office workers juggling multiple gadgets.
- Bluetooth 5.0 & 2.4G Wireless Dual Connection -- The latest Bluetooth 5.0 enables cable-free, clutter-free connection with a 33FT(10m) delay-free range. The 2.4G USB receiver (stored under the keyboard) suits desktops/laptops without Bluetooth. It’s plug-and-play with no extra software or drivers needed, ensuring stable, reliable use for lively on-the-go girls and office users.
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- Full-Size Compact Keyboard with Number Pad & Hot Keys -- This cute, stylish keyboard comes with a numeric keypad, 15 handy hotkeys and FN lock, featuring all essential keys for easier, more comfortable typing. Its industry-standard layout includes special hotkeys: a lock key for screen locking and an FN lock key to customize F1-F12 as media or function keys, boosting workflow and productivity for efficiency-focused female office workers.
A cautious investigation would:
- Photograph every marking and trace before probing.
- Use a multimeter to identify ground, supply, reset and likely signal nets.
- Look up the exact chip documentation where available.
- Confirm voltage levels before attaching a logic analyzer or USB-serial adapter.
- Probe passively first and assume firmware access may be locked.
Unknown pads should never receive an external signal merely because their labels look familiar.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What the PCB layout reveals
The board carries the tactile switches, LEDs, touch circuitry, USB connector, charging components, test points, keyboard-matrix traces and Bluetooth section. Two principal ICs are visible on the underside. The original author judged the board likely to be two-layer from its visible routing and apparent lack of inner-layer traces; that is a visual inference, not a confirmed stack-up specification.
Repairability scorecard
| Subsystem | Practical outlook | Why |
|---|---|---|
| Case and board access | Good | The shell opens without obvious external screws, although clips and tiny screws still need care. |
| USB connector | Moderate | Resoldering or replacement is possible if pads and surrounding laminate are intact. |
| Battery | Conditional | Replacement is possible only with a compatible protected cell and verified wiring. |
| Individual switches | Conditional | A matching tactile part may be fitted, but sourcing and desoldering can be difficult. |
| Touchpad electrodes | Poor | Torn or damaged electrode patterns are difficult to reconstruct. |
| Charging IC | Poor | HXN MH is unidentified, so its pinout and substitute cannot be assumed. |
| BK3231Q and firmware | Very poor | Fine-pitch replacement, undocumented firmware and possible lockout make recovery impractical for most owners. |
| PCB antenna | Poor | Trace damage or enclosure changes can require RF-level diagnosis. |
Common failure paths
It powers on but will not pair
Possible causes include a depleted battery, faulty power switch, damaged BK3231Q, pairing-state or host-compatibility problems, and antenna damage. The teardown does not provide a tested pairing diagnostic, so isolate power, host and RF causes rather than assuming a firmware fault.
USB charging stops
Inspect the connector and solder joints first, then look for open passives or battery-protection cutoff. Do not diagnose HXN MH by applying a guessed charger pinout.
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The touchpad is intermittent
Check the overlay and electrode area for contamination or moisture, then inspect the touch-controller connections and supply rails. Physical damage to the electrode layer can be more consequential than a dirty surface.
Bottom line: an instructive design, not an easy repair
This Jelly Comb keyboard is a compact demonstration of near-single-chip wireless design: tactile matrix input and capacitive pointing feed a Beken Bluetooth microcontroller, while a small power section charges an unidentified lithium-ion pack. It is approachable to open and worthwhile to map, but undocumented firmware, uncertain charging details and delicate RF and touch structures sharply limit practical repair and hacking.
For a model-specific photographic record, see the original All About Circuits teardown. Later articles using the same title describe generic keyboard construction and should not override the component markings and observations documented for this unit.
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