Questions tagged [diagnostics]

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Could any of the following components produce an erratic waveform when they fail? [duplicate]

If I am looking at current through an ammeter inserted between the negative battery terminal and the negative circuit lead, could any of the following produce an eradic waveform where the current ...
WackyTortoise's user avatar
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Diagnosing single phase 3-speed brushless AC motor

The air conditioner Family FSA-15H has one-phase fan brushless AC motor with 3 constant speeds: High, Medium, Low. After 2 years of rare use, the fan works only on ...
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4 answers
3k views

Is there a technical reason why sensors goes from 0.5 to 4.5V volts?

Is there a technical reason why sensors output goes from 0.5 to 4.5V (analog) or 10% - 90% (digital)? I understand that for diagnostic purpose one doesn't normally want to use the full range ...
user217354's user avatar
0 votes
1 answer
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Diagnosing a transformer

I am diagnosing a 22 year old UPS (APC 1400RM) problem, the big transformer (430-7140A) is getting very hot yet the UPS works and self test reports fine. I suspect something is going to fail soon and ...
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1 answer
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Is power supply making clicking noise safe to use?

I have 12 V power supply (one of these you can find with most laptops and other hardware) with current rating of maybe 2A. When it is loaded, it works and it is silent, but when the load draws small ...
jiwopene's user avatar
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3 votes
3 answers
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Problem with SMPS input

I had this Chinese adjustable 2 kW SMPS (0-24 V and up to 60 A) for few years now and everything was fine with it, but recently it let some smoke out and blew a fuse, it could still be turned on and ...
user321181's user avatar
2 votes
2 answers
140 views

Derive voltage of LED array?

I'm trying to diagnose a faulty builder's worklight. It has a single board, a 8.4V battery, an external 8.4V DC input, and a LED Panel. What voltage would you expect at the LED panel? I'm measuring 8....
Criggie's user avatar
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1 answer
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ITS724G diagnostic

We are using two ITS724G devices from Infineon in one of our designs. We are now struggling with the diagnostic function and want to check if someone else have had the same problem and maybe have a ...
Martin's user avatar
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2 votes
0 answers
260 views

100Hz noise at hi-fi amplifier tone control after servicing power supply

I have an old Revox B780 HIFI amplifier / radio tuner. It was working perfectly fine except that it could not longer automatically search for radio stations and lost its memory of stored stations ...
ARF's user avatar
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1 answer
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What pins in Radar ECU and Camera ECU should be detected for OC, STG, and STB faults and why?

A typical Electronic Control Unit(ECU) performs Open Circuit(OC), Short to Ground(STG), and Short to Battery(STB) Diagnostics on selected internal and external pins in the ECU. For example, consider a ...
jani's user avatar
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Testing 16K SRAM in TL866 II Plus?

I have a GoldStar GM76C28A-10 16K (2048 x 8) SRAM DIP chip that I want to test in my TL866 II Plus. I don't see this chip in the list of known chips in the Xgpro v11.60 software and none of the "...
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1 answer
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Is asymmetric insulation resistance a sign of AC appliance failure?

I tracked down an AC appliance (a dishwasher) which started tripping my home current circuit breaker (RCD). I happen to have a professional insulation resistance meter and I was able to measure about ...
miroxlav's user avatar
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1 vote
1 answer
239 views

Diagnosing dead soldering-iron

My soldering iron was working fine for a few years. One day, I used it and it worked fine again, then I unplugged it then tried to use it again a couple of hours later but it wouldn't heat up. I took ...
Synetech's user avatar
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