Salvaging Components from DPF-HD1000

Introduction 
This post looks at electronic components that could be salvaged from a Sony digital photo frame, DPF-HD1000 (circa 2010).

Tear Down
Four plastic screws secure the two halves of the photo frame case. A thin prying tool was used to release the internal plastic clips.

DPF-HD1000 Front Cover Removed

Removing the front panel shows the LCD and two peripheral items, an IR sensor and an LED strip.

Internals of the Photo Frame
Shifting the position of the display shows the main Printed Circuit Assembly (PCA) and the board to peripheral connections.

DPF-HD1000 with PCA Exposed

The IR receiver was connected with a 3-pin cable to the main PCA. The markings on the sensor appear to be 28m5 and E23, but there is no data available for the part online. The connections to the sensor could possibly be determined from the cable colours.

DPF-HD1000 LED Logo Board

The small LED PCA was labelled ‘logo LED board’ circa 2011. This board was used to illuminate the Sony logo built into the front plastic cover.

DPF-HD1000 LED Logo Board Powered

From the website Panel Look, the LCD appears to be from CPT, although discontinued, and could be used for repair or paired with a converter board capable of driving 60-pin flat flex cables from various interfaces such as USB.

DPF-HD1000 LCD Part Number

After removing the 4 screws retaining the PCA, the entire electronic assembly could be removed.

DPF-HD1000 Complete Electronics Assembly

Disconnecting all the peripherals from the PCA, attention turned to some interesting components on the main PCA. The PCA was labelled ‘Sony Basic 10DW MP’.

Possible PCA Component Salvaging
The USB connectors, surface mount and vertical switches could be salvaged from the PCA. The combination card holder on the PCA was an interesting component (large component on the right of the PCA); no data could be found from the A238B marking on the device.

DPF-HD1000 PCA Side 1

Upon reviewing the passives, inductors and the common mode filter near the DC jack (bottom right) these could be salvaged and reused. Due to the age of the PCA, the SMT electrolytic capacitors are not recommended for salvaging, although they did appear in near-new condition.

For active devices, the single linear regulator 1117T near the SD card holder could be salvaged.

DPF-HD1000 PCA Side 2

Flipping the PCA shows several chips, connectors for the peripheral devices and a smattering of passives. If any external devices, such as the IR sensor, were earmarked for salvage, the surface mount connectors could also be salvaged from the PCA.

To the left of the main Amlogic controller is a surface mount switch which may be responsible for detecting rotation (movement) of the display. When shaking the PCA, the internal mechanism can be heard moving. The component marking is EnSky, however no data could be located on the switch.

There is an oscillator, possibly 24 MHz (middle PCA), driving the Amlogic controller and a watch crystal for the on-board RTC (PCA bottom right) that may be useable.

An ELNA button supercapacitor, rated at 3.3 V 0.22 uF, provided backup for the RTC. Looking at the supercapacitor, corrosion was sighted on the case of the device and therefore not useable.

Corrosion on Supercapacitor

The main controller AML6236-VB-B is not listed on the Amlogic website and is likely not worth salvaging.

For storage, Sony opted for a Samsung 2 GB eMMC, part number KLM2G1HE3F-B001 (far left on PCA2). While this component does not appear to be manufactured any more, it would be a great device for experiments. The PCB model still appears to be available (SnapEDA). Even though the component may need to be reballed when fitting the component to a new PCA, connection to micros such as ST or Microchip would most likely be possible.

The 512 Mbit DDR1 memory was provided by Etrontech, part EM6AB160TSD-5G. This part could be used for repairs.

Interfacing the Amlogic controller to the LCD was a Texas Instruments flat panel driver part number SN75LVDS83B. The datasheet is an interesting read and even contains a good summary of PCB layout techniques.

Some other active components on the PCA are the serial flash, switching and linear regulators, speaker driver and RTC. There is also an unmarked chip on the board whose purpose is not clear. Many of these components could be salvaged depending on requirements.

Component Salvaging Example
Often questions posted after salvaging blogs relate to how components are removed from PCAs. As an example, consider the removal of the DC jack from the PCA.

Setup for Component Removal

The jack component is a 5-pin device that could be desoldered although in this example it was removed using a heater plate. Firstly, all the components on the opposite side of the DC jack were removed. These components consisted primarily of passives. This side of the board was made as flat and clean as possible. Then a heater plate, in this instance a MiniWare MHP50, was used to preheat the side of the PCA where the passives were removed (beneath the DC jack). Shortly after the heating cycle, a reflow cycle was run to pry the jack from the PCA. This technique certainly cannot be used for every board and component as the component population density and board construction can have significant effects on heating.

Salvaged DC Power Jack

Other tools such as a hot air desoldering tool or a small temperature controlled oven may be better suited for the removal of specific components.

Transponder Coil Test

Introduction 
This short post details the testing of the transponder portion of the tank circuit used for the ScioSense AS3935 lightning sensor.

AS3935 Block Diagram (Courtesy Sciosense B.V.)

Sensor Board for Arduino (Educational)
A printed circuit board (PCB) was designed for the ScioSense lightning sensor which was paired with an RGB LED (8x8) matrix as a visual output device for lightning intensity. The PCB design uses the common Arduino shield footprint to suit a controller such as the Uno or another compatible controller.

3D View of Lightning Sensor PCB

Tank Circuit Testing
After reading comments from several forums regarding sensitivity concerns with the AS3935, I wanted to check the Q-factor of the recommended LC resonant tank circuit for lighting detection. The transponder manufacturer, Coilcraft, has an article describing testing with a Helmholtz coil however I was interested in driving the recommended tank circuit with the function generator and then measuring the resonance with a second transponder coil connected to a scope.

Coil Coupled Tank Circuit Measurements
Using the two-board setup as pictured below meant that the distance and alignment of each board (transponder coils) affected the measurements. The placement of the transponders in proximity to each other impacts the field coupling. Field coupling is explained well at this Electronics Tutorials site.

Tank Circuit and Transponder Measurement Test Setup

During the test setup, the highest coupled transponder voltage on the receiver transponder was measured using an oscilloscope. The two boards were fixed in position for consistent measurements. Measurements using this test process are not perfect because of the coupling factor between the coils (not unity) and mutual inductance can also affect measurement accuracy.

Tank Circuit Measurements
The datasheet for the AS3935 recommends a 10 k resistor in parallel with a 1 nF capacitor and the transponder coil for the tank circuit.

Schematic of Tank Circuit on Test Board

A second board with only the transponder coil fitted served as the detector through a connection to an oscilloscope. 

The signal generator frequency was varied and measurements were taken using an oscilloscope. The approximate centre frequency (resonant) and the corresponding 3 dB points were determined during testing. 

From the centre frequency measurements and the 3 dB points, the Q factor was calculated. Three different resistor values were tested and the table below shows a plot of the resistor values and the calculated Q factors. For the recommended tank circuit, the resonant frequency was around 494 kHz.

Tank Circuit - Measurement Data

Tank Circuit - Plot of Resistor Value vs Q-Factor

As a validation test, the FFT function on an oscilloscope was used to view the changes in the resonant frequency of the tank circuit as the the signal generator frequency was varied.

Tank Circuit Measurement Validation using Field Probe

To perform the FFT measurements, a near-field probe (Beehive Electronics) was connected to a wideband amplifier and then connected through to an oscilloscope. 

Captured in the image below is the approximate resonant frequency of 488 kHz. The test board was fitted with the suggested design, a 10 k resistor, 1 nF capacitor in parallel with the transponder coil.

Tank Circuit - FFT Measurement

Final Thoughts
A standalone transponder coil was used in this post to show that a parallel RLC circuit on a different circuit board was resonating. Validation of the resonant frequency using a field probe indicated that the measurement difference between using a second transponder coil for measurement, or a field probe was less than 2 %. For accurate resonant frequency measurements, factors such as mutual inductance in the measurement device and the equipment under test should be accounted for.

Crosstalk Test PCB (Educational)

Introduction 
The Printed Circuit Board (PCB) design in this post was inspired by the well-known signal integrity educator, and professor, Eric Bogatin. The board design was based on content shown in a YouTube video created to demonstrate crosstalk.

Crosstalk PCB 3D

Why This Design?
Following on from the PCB trace-to-trace crosstalk content created by YouTuber Robert Feranec with guest Eric Bogatin, I wanted to design a simple educational board that would allow crosstalk measurements to be made on a PCB and tested when passive elements were introduced into PCB traces. Crosstalk measurements with series and parallel resistor signal path terminations are common in many PCB designs and this PCB design was designed specifically for series terminations.

Circuit Board Design
A regular 1.6 mm board (FR4) double-sided PCB was chosen for the design. For the copper layers, a reference plane was placed on one side of the PCB and impedance-controlled traces were placed on the opposite side. Using PCB design software tools, the configuration of the trace impedance (width) was tuned for around 50 R impedance giving a 2.8 mm trace width. The 50 R impedance is given a tolerance of + 10 % as this is the standard tolerance for PCB fabrication houses in the local region.

Altium Impedance Profile 50 R for Crosstalk PCB

 

As a crosstalk PCB design features two signal traces, the spacing between the traces was set at less than a track width to ensure ample signal coupling between traces.

Crosstalk PCB 2D

As the series element, a resistor footprint was included in one of the PCB test traces.

Crosstalk PCB Resistor Linked

This footprint on the PCB provided an option to test with different resistor values and then measure the effects with suitable test equipment. A pulse generator with a fast edge and an oscilloscope are required.

The first setup on the test PCB has the series resistor on the same layer as the signal trace and the second test setup has the resistor on the opposite side to the trace, connected through vias.

Board Build and Initial Testing
For the board assembly, the Molex SMA connectors were fitted. The Molex part number is 0732512120. For the validation test, the resistors on the PCB were replaced with solder shorts.

During testing, the trace with the series resistor is referred to as the aggressor and the nearby sensing trace, is the victim. Further details relating to this setup and a further explanation can be found in the aforementioned video content with Robert Feranec.

First Test Setup with Crosstalk PCB and Pulse Generator

For validation, measurements were taken using an oscilloscope with a bandwidth of less than 500 MHz and a simple pulse generator (Microchip version) designed in a previous blog.

Pulse Generator Frequency

Pulse Generator Rise Time

With the pulse generator providing the 1.4 ns rising edge signal into the aggressor trace (CH2 blue trace), the connector at the near end of the victim trace (CH1 yellow trace) was connected to the oscilloscope.

Near End Crosstalk PCB Measurements

For a second measurement, the two ends of the victim trace were connected to oscilloscope. When the pulse was applied to the aggressor,  the signal entering and then reflecting (near and far end) was measurable.

Near and Far End Crosstalk PCB Measurements

Summary
This short post introduced a printed circuit board for testing the behaviour of signals relating to crosstalk measurements. The option to use a series resistive element was included but not tested in this post. 

The PCB Gerber files are downloadable using the link below for those who prefer to build the board and perform testing at home, school or in the lab. The Gerber files use the format as defined on this page.

Crosstalk PCB Gerber Files

PSoC I2C Address Scanner (I2C Scan)

Introduction 
This short post covers a change to a PSoC Creator project created by Bob Marlow (Infineon Developer Community) for scanning an I2C bus.

Reason for the Updated Project
While experiencing issues when communicating with a Midas I2C display (MC20805A6W-FPTLWI-V2), the I2C address needed confirmation. Upon testing with a PSoC project (I2CScan) authored by Bob Marlow, the PSoC program did not output a response to the terminal program with an I2C address even though the Midas display was connected correctly to the PSoC. This was curious because the display was newly purchased.

Test Setup - PSoC Development Board with Midas I2C Display

Narrowing the I2C Address Range
Using two hardware connections on the Midas display, the I2C address can be configured for various I2C address options. For testing, the range of the variable I2CAddress in the PSoC code was limited from 0x3A to 0x3F. A short delay (padding between transmissions) was added to the code to make debugging on an oscilloscope easier.

Status = I2C_I2CMasterSendStart(Address,I2C_I2C_READ_XFER_MODE);   

The Midas display did not respond to the read command shown above. However, after changing the code to use the I2C write command, the display responded with its expected address.

Status = I2C_I2CMasterSendStart(Address,I2C_I2C_WRITE_XFER_MODE);

Tera Term - Midas I2C Address

The captures below illustrates the I2C replies, when the 0x3F address was used with the read and write transfer modes for the PSoC function I2C_I2CMasterSendStart.

Midas Display - NACK to Read I2C Packet

The ninth bit (left MSB bit first) in the SCL clock train (yellow trace) in the above trace shows that the corresponding position in the SDA trace (blue trace) was high and therefore represents a negative acknowledgement (NACK) to the read command; the same bit position on the trace below has a low on the ninth bit (blue trace) represents an acknowledgement (ACK) to a write command.

Midas Display - ACK to Write I2C Packet

For further information, see Figures 6 and 7 in the TI document ‘Understanding the I2C Bus’ for waveforms relating to I2C ACK and NACK responses.

Code Changes
The code change mentioned in the above paragraph was implemented in the PSoC TestI2CAddress function located in 'main.c'. Other changes were made in main to suit the terminal program TeraTerm.

Testing Other Devices
To ensure the code change would work with other devices, two other I2C devices were tested; an Adafruit SI1145 light sensor and an INA219 current sensor. 

Test Setup - PSoC Development Board with SI1145 Sensor

Tera Term - I2C Address from SI1145 Sensor

 

 

Test Setup - PSoC Development Board with INA219 Sensor

Tera Term - I2C Address from INA219 Sensor

Downloads and Disclaimer
The updated PSoC Creator project v1.1, for a PSoC4 device, can be downloaded as linked below. The original project is copyrighted and remains the property of Jörg Meier Software as noted in the project source.

I2CScan-v1_1.cywrk.Archive01.zip

PCB Artwork - Coaster (Dark Chocolate Imprint)

Introduction 
In this blog, the circuit board tool Altium Designer was used to create a circuit board (PCB) coaster with an imprint on the PCB resembling a dark chocolate (cocoa) molecule.

Prototype (Coffee) Cup Coasters

Finding a Suitable Source
Before the PCB design process could be started, a suitable molecule for the PCB imprint was found online. A representation of a molecule that was more uniformly shaped was chosen to suit the shape of the PCB. Such a specific layout may not be available without manipulating the molecule’s layout.

Dark Chocolate Molecule
(Courtesy biobeat.nigms.nih.gov)

The molecule in this post could have been caffeine, tea or several water molecules however for this post dark chocolate was chosen.

Creating the PCB
To begin creating the PCB artwork for the coaster in Altium, a circular arc on mechanical layer 1, with a 90 mm diameter was drawn. The 80 mm PCB diameter used in the previous coffee cup coaster was marginally too small however the overall PCB dimension should be adjusted on a project-by-project basis.

Coaster PCB Shape and Size

Next, the names of the individual chemicals were added as top copper layer strings. The font type sans serif was selected over serif for a modern appearance. Then the bonds between the chemical text were added to the PCB on the top overlay. Various placement and shuffling of top overlay line lengths and text were needed.

Coaster Top and Silk Layers

The next step was to duplicate the top copper layer strings. The layer properties of the copied strings were changed to the mechanical top solder layer and then placed over the top layer strings. This effectively removed the top solder mask exposing the PCB copper. Having a separate top solder layer allows for manipulation of the size and placement.

Coaster Top Solder and Silk Layers

Viewing the PCB using the Altium 3D feature yields the image below for the black solder mask.

Coaster in 3D

PCB Export
The requirements of the desired PCB manufacturer were checked to prepare the PCB artwork for manufacturing. As the files for the PCB manufacturer are usually in the Gerber format, the export settings for the Gerbers should be verified with the manufacturer.

Manufacturing
As noted in other blogs, the appearance and cost of the manufactured PCB may vary based on Production settings. For the PCB in this post, a black solder mask is more expensive than a green solder mask, the latter being more common.

In this post, the PCB thickness was kept at 1.6 mm since this is usually the most cost-effective thickness, a lead-free HASL (Hot Air Solder Levelled) surface finish was chosen over a lead finish and the solder mask was produced in two separate colours, green and black, to exhibit the visual difference. Lastly, the PCB manufacturer's marking was specified on the PCB bottom side overlay.

Downloads
The Gerber file can be downloaded from the link below. The files should be checked before use.

For the Gerbers the Altium export settings here were followed.

Coaster Gerber Files

TDR Pulse Generator (Microchip)

Introduction 
This post continues a previous blog that used a microcontroller driver design to generate a fast-rising edge for educational and bench-testing purposes. The microcontroller (PSoC) in the earlier blog was replaced with a microcontroller from Microchip (ATmega16U2). The board uses the Microchip part and is powered by USB.

Pulse Generator PCB

Why Another Generator
While the previous design using a PSoC microcontroller was received well, the price of a PSoC microcontroller has become twice that of a competing device such as the Microchip ATmega16U2. Consequently, a design was produced to utilise the Microchip microcontroller.

Circuit Board Design
As featured in the previous design, a pulse train is initiated from a microcontroller (ATmega16U2).

ATmega 16U2 for Pulse Generation

The same output driver arrangement was reused on this design however the output driver was changed to a Nexperia 74AHC04 because of the 5 V supply rail (USB). A linear regulator was considered to maintain the supply rails at 3.3 V but was ultimately not included to keep the total cost as low as possible. Five outputs of the 74AHC04 driver are still connected in parallel to individual 249 R resistors. All five outputs are tied together thus providing a calculated 49.8 R at the output, CN2.

Buffered Output for Pulse Generator

Software Design for Output Pulsing
A minimal software (code) project was prepared in Microchip Studio. This application generates a pulse by direct and continuous writes to the microcontroller port. The code to generate the pulses is shown below.

int main(void)
{
	DDRD = 0x08;
	PORTD = 0x00;
	for (;;)
	{
		PORTD |= _BV(PD3);
		PORTD &= ~(_BV(PD3));
	}
}

USB hardware connections were made to the ATmega to allow developers or users to enhance the code further. The ATmega software could be developed to support USB-controlled commands. Below are some links for software that may allow for HID solutions with the USB.

https://github.com/NicoHood/HoodLoader2

https://gitlab.com/arksine.code/HID/-/tree/2.0

A Note on Programming
The post includes details regarding the programming of the Microchip part because this design is intended for the educational system or illustrative purposes.

The 6-way programming connector on the pulse board interfaces with the ATmega. The connections are designed for SPI programming. See Table 3-6 in the Atmel ICE document for information concerning connections between the programmer and Microchip microcontrollers.

SPI Connector Pinouts

For programming of the microcontroller in this blog, the ‘Atmel squid’ connections were made to the pulse generator board as shown below.

SPI 'Squid' to Pulser Board

PCB pad jumper J1 should be shorted with solder to power the external oscillator.

Powering External Oscillator J1

The settings displayed below are taken from the Microchip Studio's, Tools menu, and the Device Programming item. The settings can be adapted based on the functionality needed on the board. For example, the onboard 8 MHz oscillator could be replaced with a different frequency device or the board could be redesigned to suit a crystal.

Microchip Studio ISP Clock Settings

Microchip Studio Oscillator Settings

 

Microchip Studio Fuse Settings

Microchip Studio Fuse Settings Continued

Testing the Board
Since the output driver voltage rails were changed from 3.3 V to 5 V, the output rise time (10% - 90%) was predicted to be slower.

Prototype Pulser PCA

Drive Voltage from Pulse Tester (Microchip)

 

Period from Pulse Tester (Microchip)

Signal measurements were again performed on a Keysight oscilloscope with a 20 GSa/s resolution. This board showed a rise time of 1.11 ns when measuring for a rise time of 10% to 90%.

Output Waveform Rise Time from Pulse Tester

Reflectometry Testing
Reflectometry tests were performed with a benchtop oscilloscope. The pulse was connected to the oscilloscope with a BNC Tee adaptor, and the other side of the BNC Tee was connected to a length of coaxial cable.

Pulse Tester as TDR Test Setup

The initially launched and reflected pulses were captured as shown in the image below.

TDR Capture

Engineering Files
The Atmel Studio project, schematic, Gerber and BOM files are available for download using the links below.

Pulse Generator Microchip Studio Project

Pulse Generator Schematic Rev2

Pulse Generator Gerbers Rev2

Pulse Generator Bill of Materials Rev2