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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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28 views

What are some techniques to troubleshoot a second order sigma delta loop?

I have designed a slightly modified second order (3-bit) multi-bit incremental sigma delta modulator (IDSM) in simulink (system level). The SNR that I get is 45dB, which is not as expected. But ...
-1
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0answers
55 views

Atmel Studio 7 crashes on launch with VS 2015 Shell (Isolated) Error

Recently I've installed Atmel Studio 7, but it doesn't launch and throws an error: I've tried to reinstall and fix Isolated Shell and its dependencies, including the one it asks, with any combination ...
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2answers
110 views

Strange behavior of the DALI controlled luminaires

I faced a strange behavior of a DALI controlled LED luminaires circuit. I have 48 LED luimianires with a MeanWell ELG150-C700-DA drivers connaected according to the scheme below: I commissioned the ...
1
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2answers
152 views

32.768 kHz Crystal Troubleshooting

I'm at my wit's end trying to get a 32.768 kHz tuning fork crystal to work and I don't know what I'm doing wrong. First, some background: I'm using a 16MHz crystal in conjunction with an Atmega 328P-...
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0answers
29 views

can't figure out why my micronucleus/V-USB setup doesn't work

I built a small attiny85-based board using vusb and essentially the schematic of the discontinued Sparkfun "AVR Stick" (at least on the usb/uC side; see https://www.sparkfun.com/datasheets/Widgets/AVR-...
5
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4answers
4k views

Is a capacitor bad when it looks like this?

Hello I am new to the electronics field. I am looking inside of one of my synthesizers and I see some capacitors (I think they are Mylar, correct me if I'm wrong) that look like this. I know it is a ...
2
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3answers
1k views

Troubleshoot a backplane

I have built a simple bus backplane from stripboard and 40-pin female headers for a computer project I am working on. When I tested the backplane to make sure that it functioned, I found that it's ...
0
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1answer
55 views

Identifying damaged, burnt out, or missing components [closed]

Is it possible to deduce the identity of damaged, burnt out, or otherwise missing components (or suitable substitutes)? For example, below is the PCB of a 2 speed electric razor I've disassembled. ...
1
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2answers
132 views

MCU overheating

INTRODUCTION I've designed a custom board featuring a SAME54N20 MCU. This is the third board I assembled but I still haven't got any to work: I didn't get the first board to connect to my PC. My ...
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1answer
62 views

Best way to locate a 4k stray resistance between 2 bus lines in a PCB?

I have a faulty PCB which is showing an unexpectedly low resistance between certain pairs of bus address lines. I'm measuring a little over 4k ohms between these bus lines, but according to the ...
19
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6answers
2k views

Why would a buck converter IC fail and blow up?

I have a deployed design in which we are experiencing a high (~4%) failure rate in the 12V to 5V step-down buck converter portion of the PCB. The buck converter's role in the circuit is to step down ...
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2answers
60 views

AL5802 LED-Driver works on the breadbord, but not on its (seemingly functionally identical) PCB

TL;DR: I'm working on a project that incorporates (besides other things) two AL5802 linear LED-drivers in parallel. Unfortunately, I felt balsy and had my complete PCB made in China before testing the ...
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2answers
420 views

Why is the MCP601 better suited than the LM833 for single supply applications?

Still not answered, please need some help. If you guys don't know the answer don't be afraid to admit it, but I want to generate discussion around potential solutions/calculations and not semantics ...
-4
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1answer
158 views

Tesla Coil Troubleshooting Help! [closed]

A couple weeks ago I decided to build a tesla coil and after a decent amount of research and building time the coil could only light up a light bulb. I have tried many things to fix it but all to no ...
0
votes
1answer
91 views

Overvoltage at input causes small jump at IC input pins

I have a PCB with voltage regulator (5V), op-amps, 2 multiplexers, 1 counter, several pots, caps, and resistors. I supply 9V. The voltage regulator converts it to 5V. Without connecting any ...
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0answers
89 views

How to troubleshoot a switched-mode power supply?

I am trying to repair a switched-mode power supply, but as of now I have no success. The problem can be described as following: The supply does not output any voltage whatsoever. The fuse never ...
4
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1answer
172 views

Observing ethernet auto-negotiation packets using oscilloscope

In an answer to one of my previous posts seen here: Verifying 802.3 auto negotiation, @Zac67 mentions that by using an oscilloscope I could observe normal and fast link pulses that are sent in order ...
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0answers
116 views

CircuitLab Simulation issues with an Audio Power Amplifier

I'm trying to simulate and eventually build a Blomley amplifier described here and here. When I simulate it as it is in Wireless World, it seems to work okay and my measurements make sense. But when ...
0
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1answer
42 views

Troubleshooting an op-amp for amplifying a low voltage AC input

I am trying to amplify a low voltage AC input with a gain close to 5. It has a 0 DC offset and about 300 mV of AC amplitude, at 250 kHz. This is my first venture into electrical engineering and I’m ...
0
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2answers
151 views

Troubleshooting expensive potentiometer

Tl;dr tested pot and it doesn't show any variation across center pin. Is it reasonable to conclude it is the broken part? Hey everybody, so recently a coworker and I were reassembling an expensive ...
1
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1answer
44 views

Schmitt trigger issues… lumpy outputs and wrong switching voltages

I'm trying to implement the Schmitt trigger found in "CMOS" by J. Baker. Here's what the circuit should look like: And this is how the transistors should be dimensioned to achieve switching voltages ...
0
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1answer
51 views

Why is the logic probe reducing current from the power supply?

I am troubleshooting a very basic circuit using an inexpensive logic probe to check values. Typically when I use the probe I see current output go up about 7mA, which I assume is to power the sound ...
0
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1answer
83 views

Troubleshooting Dimmer Circuit [closed]

First off I do apologize for my ignorance, I know very little on the topic so please be patient. I have one of these that are broken http://www.smartliving.com.au/z-wave-in-line-dimmer.html Its a ...
0
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0answers
82 views

Next step when troubleshooting a PS/2 keyboard PCB with good cable

I received a PS/2 keyboard (TypeMatrix 2020) which was known to be broken, with some hope that I may be able to fix it. I don't have a lot of experience with electronics, but I know the very basics. ...
2
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1answer
162 views

Computer won't post / Beep unless Unplugged for a few hours [closed]

I'm experiencing this issue for almost a year now. It is slowly getting worse. My motherboard is Gigabyte GA-Z77X-D3H and my PSU is Corsair CX600. The source of the problem most likely has to do with ...
3
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1answer
228 views

Troubleshooting 4066 as a button hack

I have an Arduino project which needs to simulate a human button press on a third-party board, an 883LM garage door opener controller. The other board has its own power supply which is separate from ...
2
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3answers
304 views

Troubleshooting wien bridge oscillator circuit with 741 op amp

I built the standard Wien bridge oscillator circuit using the UA741CN op amp IC, however I am not getting any oscillation. I am powering this circuit with two 9V batteries. I'm using the values R1=...
0
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1answer
105 views

Troubleshooting noisy FET buffer for contact mic

I'm trying to follow the schematic on this page to create a preamp/impedance matcher for a balanced piezo contact mic. I've reproduced the schematic below. I've built it on a breadboard and I'm ...
0
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0answers
103 views

Looking for Beckman Industrial 9022 Manual

I recently acquired my first oscilloscope. I got it for free which is awesome. I am needing a manual for it but have scoured the web looking for one to no avail. I read a response on here, while ...
0
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0answers
72 views

Troubleshooting help with my continuity tester circuit

I don't know whats wrong with my circuit. I wrote my readings down in my picture attached, I have measuring 9.6V on both sides of R1 therefore the base of Q1 has 9.6V. However, 9.6 volts is also seen ...
3
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4answers
2k views

SMPS output voltage too low - what to look for?

I have an old switching power supply for HP 712/60 workstation (+5V, +3V3, +12v). It was working about ten years ago when i've last tried to boot the system, but now one of the output voltages is at ...
4
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1answer
332 views

Switching Voltage Regulator Problems

I'm new here, so forgive me if I breach any forum protocols in the asking of this question. I have designed a voltage regulator scheme for a guidance system on an aerial drone. All components ...
0
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0answers
71 views

RF Interference and Metal Enclosure

We have a product (optical detector), one client had an issue with false alarms due to their radios they use on site. Did some modifications, added a ferrite bead to the cable and put a driven guard ...
0
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2answers
446 views

Op-Amp as comparator for driving relay stops working after short time

Ok I have an Op-Amp as a comparator, Its the TCA0372... whole amp it can source, not needed just nice. and I have a relay, http://www.mouser.com/ds/2/315/jw-catalog-1075968.pdf Its driven by 12v. ...
0
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1answer
90 views

HC-05 BT Doesnt need vcc for power [duplicate]

I'm hooking up and old HC-05 BT module and it powers even if vcc is disconnected, (if TX is high and is key is high), is it likely i fried something and it's broken?
1
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1answer
78 views

Troubleshooting my Electromagnets

While the problems I am having span across several projects of mine, the common denominator is the electromagnet present in each project. I have made three electromagnets and none of them seem to be ...
0
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0answers
278 views

Error on Lattice Diamond: “core0 incorrect response (Write: 512 != Read:0) … Problem cause is sample clock too slow or not continuous”.

Question for persons experienced on Lattice Diamond, I'm trying to test a previously developed project on Lattice Diamond. The project initially shouldn't have any problems because it was implemented ...
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0answers
95 views

Schottky heating up

I'm having some issues with a BAT54-7-F schottky diode heating up. I've asked an initial question over on reddit. Relevant part of my schematic: The LED drivers are hooked up according to this ...
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2answers
460 views

EMG, Muscle Sensor Arduino - Troubleshooting [closed]

I've been testing the EMG sensor below: http://www.ebay.com/itm/Muscle-Sensor-EKG-EMG-Developemt-Electronics-Module-Interface-Kit-For-Arduino/351850511727?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=...
0
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1answer
62 views

Simple method to find open fault in three wire power cable?

I have a three wire power cable - live, neutral and ground. My multimeter shows no fault with the neutral and ground wires, but there is an open fault on the live wire. Nothing suspicious upon visual ...
0
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1answer
142 views

busted WS2811 LED strip by overpowering, totally useless now?

Powered a 5V WS2811 LED strip with 12V by accident. It turned on for a split second, it fried a microcontroller, I noticed the smell and turned everything off as fast as I could. When i tried ...
2
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3answers
388 views

What would cause a 120 VAC universal motor to run slower in reverse?

I got a bargain on a few small universal motor that run on 120VAC and I'm trying to reverse the direction. I don't have a lot of experience with these types of motors but I do know they run on AC or ...
23
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5answers
4k views

How to create measurement points on a PCB for diagnostics?

What is the best way to implement a point on a PCB, where a voltage (e. g. output of a regulator) could be measured with multimeter for the purpose of verification of the assembly or diagnostics in ...
0
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3answers
77 views

FlipFlop outputs half voltage SN74HC74D

I first did a simulation of a simple circuit with the IC SN74HC74D and it outputs 5V, please see attached image. I made a circuit and ordered a PCB. When soldered it only outputs 2.5V(Pin ~Q_2). I ...
2
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3answers
458 views

Relay seems to fail (sticks on) when a load is present, but not otherwise - does that make sense?

I'm repairing my stove. The control board has a relay (G2RL-1A-E-HA DC12) for the oven element. When turning the bake function on, the element heats, but it won't turn off when bake is turned off. ...
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0answers
65 views

How to test if a, in circuit, complementary darling transistor is still functioning properly?

I think a transistor broke down. My knowledge of electronics is not sufficient to solve my issue, so it seems. Hopefully some better educated mind can help me on this. This question is about ...
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3answers
717 views

Tesla coil help - Spark gap not arcing despite having 12 kV

(I've searched these forums and the web and can't find anything that helps, so I apologize if I've missed something.) I'm working on my first Tesla coil and am at a loss. This is what I've got going ...
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1answer
491 views

Is it normal for an RCA cable to carry a perceptible (to a person) current? [closed]

Recently when disconnecting an RCA cable from a computer I was surprised to receive a shock from the male connector at the end of the cable. The other end of the cable was plugged into a stereo, ...
0
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0answers
147 views

Identifying 8051 garbage microcontrollers (updated)

Here I am with another question about the 8051. After researching various resources, I read in the datasheet that the ALE pin is enabled by default but can be disabled in code however I did not use ...
0
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2answers
2k views

2 Capacitor induction motor Humming troubleshooting

I have a single phase cutting SAW , 3 years old , yesterday i was cutting thick material it stalled as usually happens , but when i turn it off and then On again now it doesn't rotate , it just makes ...