Xhdata D-808 Schematic !free! Access

The XHDATA D-808 Go to product viewer dialog for this item. is a highly-regarded portable DSP radio featuring Airband and SSB support. While a full official schematic is not publicly released by the manufacturer, detailed technical documentation and internal board comparisons are available through the enthusiast community. Technical & Version History

The radio has undergone several internal revisions that significantly change the "solid features" of its circuitry:

Original Version (2017–2021): Known for its high-quality audio and adjustable coils on the main PCB (marked 2017-0829). It uses a Micro USB port and has a blue/white backlight.

2022 Revision: Retained the same main PCB date but updated the display board and changed the audio amplification. Some units in this era introduced a slight "hiss" at zero volume.

New Version (2023–Present): Features a USB-C port. It replaced variable coils with fixed chip inductors and resolved the low-volume hiss. The audio amplifier is reported to be slightly weaker than the original on very weak AM signals. Circuit Resources & Documentation

Internal Circuit Photos: You can find high-resolution internal photos and technical comparisons between the original and new circuit boards at Dave's Radio Receiver Page (N9EWO).

Undocumented Features: A specialized guide on Scribd details internal behaviors like battery protection ICs (DW01A) and MOSFETs used in the charging circuit.

Official Manuals: The standard user guides covering operations and specifications are available on the XHDATA website. Key Hardware Features xhdata d-808 schematic

Finding a complete, official schematic for the XHDATA D-808 can be difficult as the manufacturer does not publicly release detailed service manuals. However, the radio community has documented its internal architecture extensively through teardowns and partial schematics. Internal Architecture Overview

The D-808 is a Digital Signal Processing (DSP) receiver based on the Silicon Labs Si4735 chip. It uses two main circuit boards connected by a ribbon cable.

Core DSP Chip: The Si4735 (Silicon Labs) handles the majority of radio functions, including tuning and multiple bandwidth selections for AM and SSB.

Front End: Uses a CD7358GS (clone of Toshiba TC7358) for FM and Air band processing.

Air Band Conversion: An IF of 10.7 MHz is achieved using a Princeton Tech FS8308 PLL, which is then fed into the Si4735. Audio Power Amplifier: Uses a CS4863 (clone of LM4863).

Microcontroller (MCU): Often hidden under a black epoxy "blob," making direct identification difficult, though it supports a serial SWD interface. Versions and PCB Differences

When looking for schematics, you must identify your radio's version, as the internal layouts differ significantly. The XHDATA D-808 Go to product viewer dialog for this item

Original (Pre-2021): White backlight and a Micro-USB port. The PCB includes multiple adjustable coils and trimmer capacitors for factory alignment.

Revised (2021-2022): Amber/Yellow backlight but typically retains the Micro-USB port.

New Version (2023+): Identified by a USB-C port and rubber feet on the bottom. This version has a redesigned PCB with a drastically reduced component count and almost no manual adjustment points, which some enthusiasts claim leads to lower overall sensitivity. Where to Find Schematics Gary pulls apart and examines the XHDATA D-808

The Future: Will XHDATA release an official schematic?

As of 2025/2026, it is unlikely. The D-808 is being slowly phased out in favor of the newer XHDATA R-108 and the upcoming "D-808W" (Wi-Fi version). However, legacy support remains strong on Chinese forums like Hellocq.net and radiomanual.info.

Pro tip: If you search for "XHDATA D-808 schematic site:radiomanual.info", you will sometimes find a scanned copy of a handwritten correction that XHDATA sent to an early reseller. Bookmark that site and check monthly.

Problem 2: "SSB is Distorted"

Schematic check: The Si4735 uses a 32.768 kHz crystal (Y1 on most boards). A drifted crystal causes the BFO (Beat Frequency Oscillator) to go sharp. The schematic will show you the load capacitors (usually 12-15pF) next to this crystal. Replace both the crystal and caps.

1. Official Source (Limited)

XHDATA official website – They do not list schematics for public download. Contact their support directly: support@xhdata.com.tw
Request it as a service technician for repair purposes.

9. Repair and modification guidance

Replace electrolytic caps with low-ESR audio-grade equivalents keeping polarity and voltage ratings.
For noise reduction, add small (10–100 nF) NP0/C0G ceramics across op-amp supply pins and close to ADC/DAC Vrefs.
To improve headphone drive, consider upgrading the headphone amp IC only if PCB footprint and thermal dissipation allow.
When changing op-amps, match input bias current and output swing; check for required supply headroom and stability with existing filter caps.

3. The "SSB Twist": BFO and Architecture

One of the main selling points of the D-808 is its Single Side Band (SSB) performance. In traditional radios, SSB requires a Beat Frequency Oscillator (BFO) and a product detector.

Virtual BFO: In the D-808 schematic, you will not find a dedicated BFO component. Instead, the Si4735 generates a "virtual" BFO internally. The DSP shifts the local oscillator frequency to effectively re-insert the missing carrier for SSB demodulation.
Clarifier Control: The fine-tuning knob (Clarifier) is tied to a rotary encoder that adjusts the internal registers of the DSP chip, allowing the user to fine-tune the frequency in 10Hz or 50Hz steps to clarify voice audio.

11. Documentation & schematic reading tips

Trace power nets first to ensure correct rails before probing signal paths.
Annotate part numbers and cross-reference with PCB silks for replacements.
Use continuity and diode-mode checks around connectors, power switch, and ESD diodes.

Schematic reading guide (how to approach the actual PCB/schematic)

Start at the power input and trace rails.
Locate sequencing IC or MCU and follow outputs to transistor driver stages.
Identify the bass drum voice and trace its oscillator/envelope — it's often central and easiest to test.
Map mixer summing resistor network to find voice output nodes.

If you want, I can:

Produce a labelled block diagram mapping these blocks to a photographed PCB or a specific D-808 schematic revision (please upload the schematic image or PCB photo), or
Provide a parts-replacement list for common failures (caps, op-amps, transistors) tailored to a board photo or BOM.

You seem to be looking for a schematic diagram for the XHData D-808, a type of shortwave radio receiver.

The XHData D-808 is a popular, compact, and highly-regarded SDR (Software Defined Radio) device used for receiving shortwave radio broadcasts. It's widely used by hobbyists and shortwave enthusiasts for its capability to receive a wide range of frequencies with good sensitivity and selectivity.

However, obtaining a detailed schematic diagram for such a device can be challenging due to several reasons:

Intellectual Property Protection: Companies often protect their intellectual property, including schematic diagrams, to prevent copying and to maintain a competitive edge.
Availability: Some manufacturers may not release detailed technical documentation, especially for devices that are designed to be used as-is, without modification.

That being said, here are a few suggestions on where you might find information or resources related to the XHData D-808: