Questions tagged [troubleshooting]

For questions about troubleshooting circuits. Please note that repair questions must involve specific troubleshooting steps and demonstrate a good understanding of the underlying design of the device being repaired.

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How to troubleshoot 18650 battery charger in handheld vacuum cleaner? [closed]

I am trying to fix a handheld black and decker vacuum cleaner. It worked for almost 3-4 years and all of a sudden stopped working. Even on full charge, it was running for like 5 seconds and then dies. ...
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3 answers
147 views

My Wien bridge oscillator doesn't work, what could the problem be?

I suspect I am making a probe connection mistake, but couldn't figure it out. The circuit works fine in LTSpice but I don't get anything in a real experiment. What might be the problem?
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2 votes
2 answers
103 views

Troubleshooting simple JFET preamplifier design

The circuit shown below (with actual measured values) simulates correctly in as much that it provides some gain. When I have built the circuit connected it to a signal generator using a 1mVp-p zero dc ...
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1 answer
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DC-DC converter fault output

We have a design using 4 EM2130L02QI dc/dc converter all with very similar routing and component placement. the output gets shorted to GND and never changed . the same board that contain with another ...
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1 vote
2 answers
105 views

Relay system not always working

I've got a project I just put in place and I've run into troubles and it's a little above my knowledge level so I'm looking for some suggestions. Goal: Control a 220vAC pump from 2 locations ...
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2 votes
2 answers
84 views

Help troubleshooting an unstable 595 shift register

Summary I am looking for help troubleshooting a couple of shift registers that seem to be unstable in a digital wall clock that I've built back when I was active in this stack, back in 2014. More than ...
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2 votes
1 answer
115 views

Why does testing with multimeter fix my circuit issues?

I am using this heater along with this thermocouple and this amplifier and am just trying to be able to set and hold a consistent temperature. I have the heaters connected to a transistor circuit and ...
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0 votes
1 answer
75 views

How to monitor your code execution written for any electronic device while they are operating?

I am working on a mobile robot that includes motors, proximity sensors, encoders, and MCU. I am powering my MCU CC1350 Launchpad using the onboard power supply. The IDE I am using is Energia IDE, ...
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0 answers
74 views

Tiny output on high voltage multiplier

A DC voltage multiplier that I built uses a fly back transformer that outputs 15 mm arcs at a maximum (on its own.) When attached to the capacitor/diode multiplier circuit, it produces cm sized arcs ...
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0 answers
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Hi how can i diagnose smps fault

is possible to diagnose/pinpoint faulty components on a smps example lcd tv powerboard using the rosin atomiser short finder techique as i was under the impression that all faulty components on a pcb ...
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1 vote
0 answers
59 views

Induction-heating-circuit doesn't draw any current

I've tried to build an induction-heating-circuit, but it doesn't draw any current from my adjustable transformer, no matter which voltage I give it. I planned to run it from mains-voltage (230V-50Hz). ...
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0 votes
2 answers
106 views

Any good resources on general circuit troubleshooting techniques? [closed]

Yesterday, I spent 3 hours troubleshooting an issue where my car had no electrical power and couldn't start or crank. After carefully studying the car's circuit diagrams, removing panels and testing ...
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neutral to ground voltage in ungrounded Y connection

A 2 MVA transformer 13.8kV Delta / 400V Y ungrounded neutral the voltage at the LV side of the Main circuit breaker terminals between the neutral and ground is 70 Volts, so, the technician isolated ...
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  • 817
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1 answer
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Need help troubleshooting problem with RFID antenna

I do computer support in our public library. Lately I've run into some issues with the RFID readers we use for our check out and staff stations. I'm trying to troubleshoot the problems we're having, ...
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0 votes
1 answer
79 views

How to drive this solenoid + littleBits?

I have a 5V solenoid, and I am trying to power it from littleBits. I had a littleBits servo bit and cut its wires. The orange wire should be control wire. The reason I want littleBits is because I am ...
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  • 109
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1 answer
94 views

Tenma 72-320 scope no trace need help

I am working on a 72-320 Tenma scope. It was supposed to have worked before it was put on a shelf, and after being taken off the shelf it has no trace. I'm pretty sure it's the power supply, but I'm ...
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0 votes
0 answers
132 views

Opamp gain seems too high in dc servo circuit

Hi I’m rather new at troubleshooting TI TL074CD oapamps. I have an amplifier with left and right channels that have independent dc servos. I’ve tripled checked the connected component values, and ...
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0 votes
2 answers
97 views

THAT1646 Distortion on output signal

I am working on an audio project using the THAT1646 balanced output driver (project is a hi-fi mixer for studio insert gear). The project uses a bipolar +/-15V supply. I am experiencing distortion on ...
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14 votes
6 answers
1k views

Can I get help troubleshooting a simple hobby electronics circuit? Multimeter not measuring current drawn

I am following the experiment in the popular electronics book - "Make: Electronics third edition". However, when replicating one of the experiments mentioned in the book (specifically ...
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0 votes
1 answer
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Testing a Split Core Transformer based energy monitor circuit using a breadboard

I'm trying to validate my wiring for a variation of this circuit: which is taken from https://www.poweruc.pl/blogs/news/non-invasive-sensor-yhdc-sct013-000-ct-used-with-arduino-sct-013 Before I ...
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0 votes
1 answer
420 views

Weird readings with INA219 Current/volt sensor, Arduino and big, fat scary Lipo

I have a strange situation with an I2C INA219 current/volt meter module (datasheet). In front of me, I have a rather scary 16.8V lipo - its positive output is on the VIN+ of the INA219. The VIN- leads ...
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0 votes
1 answer
63 views

Amplifier clipping output signal [closed]

I constructed a noninverting amplifier with a sine wave input (0.5 Vpp) and observed an output signal that was clipped equally in both the positive and negative regions, to about 2.5 Vpp. I tried to ...
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0 votes
1 answer
130 views

Anyone having a GSM module please confirm. Is it normal to have the terminals of SIM800L EVB antenna shorted?

My SIM800L-EVB GSM module wasn't registering to network even after providing good power supplies. On troubleshooting I found that the terminals A and B, to which the antenna attaches(see img attached) ...
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1 vote
2 answers
162 views

MAX6675 k-type thermocouple ADC is giving high readings

I have designed and built a small fairly simple circuit that uses a MAX6675 chip to take temperature readings from a multiplexed array of 16 k-type thermocouples. Datasheets: MAX6675: https://www....
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3 votes
2 answers
292 views

4 way traffic light using 555 timer

I'm trying to build a 4-way traffic light controller in NI Multisim, using the 555 timer and a decade counter (no microcontrollers allowed). I used this as reference: https://circuits-diy.com/four-way-...
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1 answer
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HP E3631A power supply delivers ~32mA on all outputs when the output is OFF but only microamps when the output is ON

I bought a used HP E3631A DC power supply, Triple output: 0- +25V, 0-1A; 0- -25V, 0-1A; 0- 6V, 0-5A 80W With the outputs off, when I connect a DVM (HP 33401A 6.5 Digit meter) to the output on any of ...
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1 vote
0 answers
46 views

NE564 PLL chip operates on PCB only with loop filter pin 14 floating

This circuit has been implemented on my PCB. However, when I test this circuit (without the DRV135UA), it surprised me that the PLL works except Pin 14 of NE564D (V_PLL). At Pin 14, I did not measure ...
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  • 93
-2 votes
1 answer
97 views

AWFUL smell from go kart motor [closed]

I built a mini go kart with an electric scooter motor (MY6812B-12) run off 2 AGM batteries in series and a control box (two way switch, forward and backward, middle is off). I had ridden it around for ...
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  • 135
0 votes
1 answer
285 views

simple NE5532 preamplifier circuit troubleshooting - sound disappears at upper end of gain potentiometer

I'm a bit lost trying to solve an issue I'm having with the attached microphone preamp circuit. If anyone recognizes what this problem is, I'd be very grateful for any help - thanks so much in any ...
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6 votes
2 answers
1k views

Does the circuit troubleshooting tool used in 2001 A Space Odyssey exist in the real world?

In the well known science fiction film 2001 A Space Odyssey there is a scene in which Bowman and Poole are trying to locate the fault in the AE-35 unit. If memory serves, they use a tool which allows ...
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0 votes
1 answer
61 views

Monitor PSU troubleshooting (Monitor sometimes doesn't want to turn on) [closed]

My Packard Bell Viseo 223ws monitor sometimes doesn't power on. I'm guessing that it's a problem with the PSU since it sometimes works flawlessly but other times the power button doesn't even light up....
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0 votes
1 answer
583 views

Device (Rasberry Pi device called a Bobcat 300) continues to burn out power adapters

I have a Rasberry Pi device (a Helium miner, a Bobcat 300), and I'm now on my 6th power adapter for the device, as all of the previous adapters have burnt out after 1 or 2 weeks. Here is the pertinent ...
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0 votes
1 answer
72 views

Too high frequency when building an LC circuit

I am trying to build an LC oscillator for a thesis at my university. I'm aiming for ~3.5 MHz, I would a Helmholz pair with 30 windings each coil and a radius of 1.5 cm, which I calculated to have ...
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0 votes
1 answer
50 views

Photogate is unresponsive - no output signal

I am trying to use this photogate with my Arduino Pro Mini (5V.) I am having no luck getting any readings from it. I measured the voltage across the emitter and got 4.5V, which should be enough to ...
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0 votes
1 answer
203 views

Linear power supply voltage too high

I got myself a good ol' chunky linear power supply at a yard sale. The output is marked 13.8V/25-27A. Switching it on made a spectacular bang with lots of thick white smoke. No biggie, just a large ...
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0 votes
1 answer
65 views

Circuit Board Troubleshooting [closed]

The question is: "Where can I get circuit boards tested or troubleshot?" As My profile shows, I am not an EE, but I'm forced to play one at my company. The following is just some background ...
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3 votes
1 answer
106 views

Troubleshoot noise in audio mixer circuit

I have a Soundcraft EPM6 sound mixer. Recently I noticed a click noise in the right channel of a stereo input. The click seems to happen at each period of the sound wave (I feed a 2 Hz signal, and was ...
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0 votes
1 answer
61 views

Why is my level shifter outputting different voltages when connected to AC power

I'm using a level shifter (https://cdn-shop.adafruit.com/datasheets/txb0104.pdf) to interface with an LCD display (https://www.sparkfun.com/products/16398) that runs on 3.3V. When connected to a DC ...
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1 vote
0 answers
93 views

Super weird multimeter behavior, multimeter is jump starting circuit

So I have a custom PCB for a project that has an output port for a pump. The pump is rated for 8-24 VDC, 3-35 W, .3-1.5 A. The starting voltage is 9-13.2 VDC. The PCB is powered by a 24V power supply. ...
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3 votes
2 answers
978 views

Electronic circuit troubleshooting resin - is it normal?

I have just started my first electronics troubleshooting project of trying to fix our family's toaster. One of the first things I learned was that capacitors tend to be commonly faulty parts of a ...
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0 votes
0 answers
73 views

Rotary encoder mistakes knob turned for button pressed

I'm using this encoder https://www.cuidevices.com/product/resource/acz09.pdf to scroll through a menu and I'm having an issue where when you turn it clockwise, it thinks the button was pressed (this ...
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3 votes
1 answer
284 views

Why do my FQP30N06L MOSFETs keep dying after being powered up only a few times?

I am having an issue with my circuit. Specifically, with the FQP30N06L MOSFETs failing after only a couple of runs (a run being powering the circuit). I'm using a 24V DC power supply and originally ...
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0 votes
1 answer
118 views

Transformer is generating less voltage than expected

simulate this circuit – Schematic created using CircuitLab I was tried to make a super simple inverter (consisting of a transformer, a single MOSFET, and a capacitor,) which is capable of ...
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1 vote
1 answer
128 views

Help identifying broken component

I have this control board from the charging station of a robot lawnmower. The board broke after a failure with its power supply. The board was powered by a 12v lead-acid battery, with a DC-DC ...
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0 votes
0 answers
35 views

Troubleshooting intermittent faults

I recently encountered an issue with an assembly machine: After sitting idle overnight (or sometimes just over lunch, upon pressing the start button the machine would perform the first step of the ...
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1 vote
0 answers
85 views

What type of SMPS is this?

What specific type of SMPS is this? I'm working on troubleshooting no power out. I'm having trouble finding comparable circuits so I can learn how it works. It appears to be some sort of resonant ...
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  • 67
0 votes
2 answers
95 views

Power supply is flashing and clicking

I tried connecting the output of my 12V 5A power supply to a Peltier module (TEC1-12710) which has a maximum voltage of 12V and max current of 10 amperes. Following this, the power supply LED started ...
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0 votes
0 answers
167 views

TRIAC Failure - Short between input and gate?

I am having a spot of trouble with a TRIAC (T2535-600G) whose gate is triggered by a PIC microcontroller (PIC12F1501)through an opto-isolator (MOC3063SM). Normally, the TRIAC, labeled U2 in the ...
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1 vote
1 answer
49 views

Heat Sensitive Fan Project not providing desired output to fan

I recently built a circuit I found online for a temperature sensitive 12 volt DC fan for the summer. The output seems to be regulated to around 0.23 amps which isn't enough to power the fan. I'm still ...
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2 votes
3 answers
146 views

High pitch noise when resistive heating elements turn on

I am a service engineer for a company that manufactures lab equipment. I want to ask for electrical engineering help with a problem. We make a product that consists of two parts, one of which is a ...
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