Questions tagged [reverse-engineering]

The process of taking a completed system and determining details of its design; may have legal limitations or ramifications in different jurisdictions

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Help reverse engineering an RS485 adaptor

I'm trying to reverse engineer a RS485 shield for a Raspberry Pi 3 that was part of a consumer appliance; I'm trying to repurpose it for other projects, but I wonder if it has ever worked. I don't ...
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79 views

Understanding/simulating an old amplifier power supply

I have an old amplifier that was home-built by someone, and I'm trying to reverse-engineer the power supply (for a start) to understand how it works, and to educate myself. However, I cannot get the ...
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1k views

What is the easiest way to extract the schematics from a physical PCB?

I have a PCB containing a power amplifier. I want to extract the schematics from it. It would take a few good hours, but it is achievable. Is there a tool to help me speed up the reverse engineering ...
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68 views

How to (generally) identify a temperature sensor? [closed]

What should be the approach to figuring out what a temperature sensor is, when taking apart an appliance or “reverse engineering”? This has come up in a couple scenarios for me recently: I am ...
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105 views

Reverse engineering PCB [closed]

I am trying to obtain the layout and eventually netlist/schematic for PCBs I have. I am wondering what others have tried to understand how a piece of hardware works, obtain a reference design, and ...
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107 views

RS485 Protocol Reverse Engineering & Replay Challenges

I'm trying to reverse engineer the RS485 protocol used by my home heater/AC. This protocol handles communications between the wired remote control (WRC)/thermostat and the main heater/ac indoor unit (...
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1answer
71 views

Panasonic RX-DT860 mod, how to unmute audio signal?

I have this older terrific sounding Panasonic Boombox RX-DT860 (huge!) and the laser unit of the CD-player died and cannot replace it. The Boombox also lacks an AUX-input, so time to change it, time ...
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1answer
95 views

How does this electromagnet control circuit work?

I am reverse engineering an electromagnet control circuit in isolation (I do not have the original controls or wiring diagram). I believe applying 12VDC should trigger the respective magnets, but it ...
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123 views

How to import .csv file using Pulse View?

I used an osciloscope to analize a JTAG communication, I exported the data as .csv file do that I can decode it. I'm using PulseView to do it. But I'm having problems to import the .csv file to ...
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606 views

Help discovering communication protocol used on faulty LCD matrix display

I own a device that has faulty 256 x 64 dot matrix display (flat cable damage + some bug infestation). After a disassembly I discovered that display is connected via 20-pin connect (soldered pins). I ...
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72 views

I'm looking for an SMD diode in a (small) haystack, hearing aid repair [closed]

It works, but it buzzes through the earpiece if you turn up the volume much, I'd like to do some signal tracing, but first I'd like a schematic. I found one using 3 NPN transistors that might be close,...
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1answer
91 views

Interfacing with unknown MCU (COB), unusually high current on input pin

I recently got an oscilloscope with a logic analyser and their first mission was helping me in reverse engineering the communication protocol between two 15-20 years old unknown MCUs (COB). The goal ...
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103 views

Reverse engineering of metal detector

I am a junior electronics engineer working on a project related to a metal detector. I am facing a problem. The signal from the op-amp (circled) is going into the analog switch (CD4066 IC, circled.) ...
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81 views

Reverse Engineering RS-485 Signals - Floating Issue

I'm currently trying to reverse engineer RS-485 signals, see waveforms below. As you can see, Signal 1 (Yellow) and Signal 3 (Purple) are a differential pair and seem to be floating. Here's a closeup ...
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131 views

Coaxial Cable Wiring on PCB (WiFi-Card)

*This post is just serving it's purpose as a discussion in case somone chance upon the same situation as me I'm really really new to this, so please bear with me. I got this PCIE wifi card from China, ...
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405 views

Dumping the content of a Toner Reset Chip using an Arduino UNO through I2C

I am trying to dump the content of this Toner Reset Chip using an Arduino UNO. I read a lot about these chips and the most intriguing with this one is that it only has GND, CLK and DATA pins. There is ...
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82 views

Identifying an inductor

I'm trying to reverse engineer a circuit here. I have almost all of the items identified, down to their specifications, except two inductors I'm not very familiar with inductors, so I figured I'd ask ...
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1answer
46 views

Help designing a data acquisition module

I'm prototyping a shoe that reads the pressure distribution of a person's weight as they walk. In order to accomplish this, I need to design a Data Acquisition circuit board that will be compatible ...
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1answer
118 views

How does this soldering iron sleep sensor circuit work?

I recently built a unisolder soldering station and am struggling to understand how the detection of the soldering iron within its holder is implemented. The unisolder board itself provides a 3-pin ...
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1answer
169 views

Camera external trigger; What is the shutter signal?

There is a Sony RX10 III camera which also has a external trigger for it. The goal is to send a signal from a micro-controller (Arduino & optocoupler in between) to release the shutter. I thought ...
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58 views

Full-wave rectifier circuit with non-grounded center tap

I'm troubleshooting a full-wave rectifier power supply circuit and have come across something I've not seen before and I'm not quite sure how it works. The center tap of the transformer is grounded ...
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1answer
90 views

What exactly is this op amp being used to do? Bandpass filter?

I am trying to identify the major functions of the different portions of this "clap on, clap off" circuit for a project. It's unclear to me what the purpose is of the section circled in ...
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1answer
77 views

"TTL OUT" on PCB

I was wondering what this TTL OUT means and what type of cable it takes. I think it might take a display or a camera but unsure.
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74 views

Troubles reverseengineering a weight scale

I'm starting a project of wireless body scale, so I bought a scale on Amazon to see the electronics inside. The scale uses 4 load cells, a half-bridge, 4 metal electrodes, a Bluetooth module and a ...
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4k views

Why split the resistance on either side of an LED?

In the circuit below, is there any reason why we can't combine R1 and R2 into one 4 kΩ resistor in either location? simulate this circuit – Schematic created using CircuitLab I am reverse ...
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62 views

Controlling Yihua 995D for USB control

I recently purchased a YIHUA 995D SMD Rework Station and me being the geek that I am wanted to see if I could perhaps control it (via USB/ATMEGA) by using my PC and touch screen instead of physically ...
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60 views

Philishave (Norelco) HS550 reverse-engineering

My first question here. Image is schematic for Philishave (Norelco in US) HS550 shaver - 110V-230VAC. I am puzzled how this works. I think that on the early part of the positive half cycle the supply ...
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150 views

What is the purpose of this current sense resistor in my arc lighter?

I have an arc lighter similar to this one: The switch failed after a couple days (typical Chinese garbage), so I took the unit apart to replace it. Also, due to its operating frequency (~16Khz), it ...
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1answer
81 views

Need help identifying SMD DFN-6 component. Top marking 26T6 TIW 957M

I've been trying to reverse-engineer this circuit but I'm an ME, so my knowledge of electronics is limited to pretty much Arduinos. I have a simple circuit and I'm trying to identify one of the ...
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1answer
124 views

Figuring out transmission protocol in cheap wireless door bell

Due to boredom I've tried some reverse engineering of simple cheap wireless ring bell which uses 433.92MHz transmitter and receiver via OOK modulation. It sends several times the same information. On ...
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55 views

Radio - Amplifier Connection

This is my first post here, so please give me feedback on how I can improve in the future. Background I am trying to reverse engineer a Becker Grand Prix Stereo Radio with an external amplifier. On ...
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2answers
134 views

How does this YouTube video's author identify pins with multimeter?

I was watching this video on JTAG. It is mostly too difficult for me to follow, and I will likely learn more about UART first before returning to this. At around 13:00 he uses a multi-meter to ...
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54 views

Understanding a power switch circuit that includes Schottky diodes at its input

In the following design, I couldn't find the datasheet for the part U25. All I could find from Orcad that chip part name is: G5027C. Anyway, I don't have contact with the person who created this ...
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1answer
40 views

What serial protocol has 60hrz cycles?

I'm tapping the ribbon cable interface between a HVAC control board (relays, etc) and display board (membrane panel + led display) to reverse engineer how to change the set point programmatically. I ...
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1answer
212 views

Purpose of this IC in USB 3.0 Hub

I'm trying to design my own USB 3.0 hub based on this commercial design, I can understand everything in this design except the usage of IC "ASM1543". Unfortunately there is no datasheet ...
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1answer
95 views

Can the motherboard of a inkjet printer be reprogrammed to do something else? [closed]

The motherboard of an inkjet printer has some useful functions - controlling position of the printhead, it has axis movement etc., which a plotter would need. Is there any way to reprogram the ICs to ...
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1answer
71 views

Unsure of the role of these transistors while reverse engineering a keypad PCB

I am trying to reverse engineer this PCB from a keypad to use it with an Arduino, but my transistor based knowledge is a bit lacking. I have gotten this far with regards to the architecture of the ...
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1answer
429 views

Reverse-engineer pinout of capacitive touchscreen

I'm interested in reusing the capacitive touchscreen of my old iPad. (As a learning experience -- I'm aware that this project will cost me more than just buying a new capacitive touchscreen would.) ...
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149 views

Which differential protocol to use when redriving Ethernet?

I want to redrive a 100-BaseTX signal on a board. The signal is to be redriven 3 times (by the same setup). On one end is a STM32 NUCLEO-F767ZI board, and on the other end is a GbE switch including ...
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2answers
97 views

Need help with IR Transmitter circuit

I'm working on IR transmitter circuit. But R77 feedback resistor creating confusion about its working. I know it's acting as a current limiter to the LEDs but confused about its role in feedback. Can ...
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1answer
146 views

Mystery SOT-143 Part on Magnetometer

I'm trying to understand the operation of a single coil magnetometer (marketed as "fluxgate", but with only a single coil). I've backed out the schematic as shown. The coil is driven by a ...
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1answer
110 views

Need help with an IR demodulation circuit

I'm trying to reverse engineer a PCB and made a schematic. The bad thing is I only have PCB images from both sides, not the actual PCB. This PCB is used to detect a very small black object spinning at ...
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1answer
43 views

Unknown pads on board

I'm analyzing a board for some device (game handheld console). I've found a simple SPI flash on it (W25Q) but there are 2 pads exposed for what I assume is factory testing (there are no other pads ...
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1answer
135 views

Some segments not working on 7 segment multi led digital clock

I have this old homemade digital clock which i'm trying to revive. It has sentimental value as it was built by my dad in his youth. The problem is 2 of the segments only sometimes light up on the ...
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105 views

UART - Logic Analyser

So I've been working on getting UART access to the head unit in my car; I've got the schematics of the unit and found that TX3/RX3 on the Renesas SH7750 are presented externally - along with 3 "...
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4answers
3k views

What is this IC Chip on this circuit board?

Very new to electronics outside base knowledge. This board is from a small smartphone toy, where pressing and holding the button displays 1 color on an attached RGB LED and quickly double tapping the ...
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2answers
1k views

Capacitive moisture sensor not quite working

I have spent the past few days trying to reverse engineer a capacitive moisture sensor I ordered from eBay a while ago. The particular one I received looks like this: What fascinated me about this ...
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6answers
495 views

10Ω series resistor in output of headphones amplifier

I managed to reverse engineer a headphone amplifier in a USB DAC that I bought on aliexpress. As I expected there is a electrolytic capacitor in series to the output, but there is also a 10Ω resistor ...
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319 views

Zener diodes with low forward voltage drop

I've designed a number of boards which utilise different kinds of diodes, and thought I had a good handle on how they work and their properties. I've been doing some reverse engineering work and ...
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2answers
319 views

How to identify an unknown protocol with a logic analyzer?

I have this Inbras electrolyte analyzer, a rebranded version of the same device manufactured by Diestro. It uses a PIC18F87K22 (master) which communicates with the sensor using a PIC12F629 (slave) ...

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