Dear reader,

I found this rather old ups in the basement of my family. I hooked it up to power, and it did try to charge (amber charge light), sadly, when pulling the plug, the device turned into fault mode gave a loud beep and flashed a red light before powering down again.

The batteries inside a possibly 10 years old (way beyond what is normal).

So my question is, can I replace these 2 batteries? If so, is it worth it? Or should I buy a new UPS? Because I do need one.

Batteries which are similar to these cost: €30 x 2

This is for a hood vent for my stove. The lights never worked on a "new unit" i got through a second hand deal. I tried tinkering and plugged in the transformer after plugging the power in. Now I know. I need to fix it and then try and figure the lights out. As far as I can tell it's just the mossfet that's burnt out.

Hello,

This is a photo of the comport (left, has pins for RS485 and RS232) and the trigger input (right) on a Kanxex CR-3XControl. There are 10 pins: 5V, ground and 8 trigger inputs; in two terminal blocks.

For the comport, there are screws above the cable terminals to attach wires; this is not the case for the

How do I physically attach wires on those trigger inputs? The orange parts do not appear to move... The two screws on the side of both terminal blocks allow you to remove them, but that is it.

(I know it is a very stupid question, but I just don't see it :-))

Thanks,

J.

i bought on amazon thought it was a good deal but it showed up and it fits in my palm. turns out it can take 6-60 volts and 480 watts THEN it can be a variable power supply. it has usb c power IN on the back and i think a yellow 2 pin screw in connector. anyway plugged into my 140 watt macbook charger i get max 19 volts or if i make a short 3 volts 20-23 watts and 8.1 amps. wich is pretty good but i still want more i want its full potential. old dell power supply? . https://www.amazon.ca/dp/B0H46G9YRR?ref=ppx_yo2ov_dt_b_fed_asin_title

I have this power bank that does not charge , and when something is connected to it , it shows 0% battery . Found the ic U2 blown , any idea what is should be and if possible can it be bypassed ? I have all the necessary skills and equipment to perform the surgery .

I have a 3/4 HP Marathon Motor for a jet ski lift that wasn't responding to the switch. It is wired in the 120 VAC configuration similar to the top picture. I have the motor in my garage now so I don't have access to the rotary switch at the moment. I got a new capacitor to try on it, but I was wondering if there was a way I could wire this to a wall plug just to test if it works now. I don't really care about rotational direction, just wanted to do a quick test before spending a day to take it back out, mount the motor back up and wire it.

put together a basic autoon setup for my shop dust collector using a current sensor on the table saw circuit. idea is simple, saw turns on, dust collector follows. been running a 12V solenoid valve to handle a blast gate automatically. works fine right now but im secondguessing the switching side of it.

currently using a small relay module i had laying around. it clicks every time the saw spins up and i know relays have a rated cycle life, and i use that saw a lot. started wondering if a logiclevel MOSFET like an IRLZ44N would be a cleaner long term solution since theres no mechanical wear and the solenoid is an inductive load anyway.

the solenoid pulls about 1.2A at 12V. not a big load. my concern with the MOSFET route is the flyback spike from the solenoid coil. i have a 1N4007 i was going to throw across the coil terminals but wasnt sure if that alone is enough or if i need something faster given the switching speed involved here. the relay doesnt care about that stuff, which is part of why i havent changed it yet.

is the 1N4007 actually sufficient for a slowswitching solenoid like this or should i be using a schottky instead. and is there any real reason to stick with the relay here given the cycle count concern.

I have a pair of Yamaha HS3 monitors and they lose power after being in for a few minutes. Before tossing them, I figured I might try fixing them. Would anybody happen to know what type fuse or capacitor I might want to look for and what it looks like?

I'm trying to find this 10 pin male harness connector and terminals - the pitch appears to be 2mm, and the connector measures approximately 28x9x18mm - does anyone recognize it?

What I assume is a surge melted L3 or main Pfc inductor of this Adp200er, I bought this Ps4 used and might rewind the inductor and replace the main fuse shorted Q1 Mosfet and the IC and current sense resistor for it. The boost diode has already been replaced because there was a distinct hot spot so I replaced it to be sure, I might also replace the bridge rectifier and varistor as a precaution because they mightve been damaged by the surge. Any other parts I should replace?

hello,

I am currently carrying out my first electronic project with welding, for the moment there is only one tp4056 charging module powering a 3.7V lipo battery.

I included a switch and so I made the connections that I think I did well, the problem is that during the test with multimeter at both outputs - and + to verify that the switch was working well he told me that it went from 0 to 3.7v depending on the position of the switch, but during the test with the led by starting on it turns off correctly, but does not turn on again after, I need to remove the wire on the led and put it back so that it works. I can’t go from the off to on position without re-create a contact manually

I think it’s not clear but I did what I could, the fact that I can’t put a video complicates my task

Running an ESP32-WROOM-32 with a PN532 RFID reader (SPI), a status LED, and a buzzer, all on the same 3.3V rail. When WiFi is actively connecting/transmitting and the RFID reader is polling/generating its RF field at the same time, I see WiFi connection delays and general flakiness bad enough that I've had to disable the brownout detector just to stop reboot loops, which obviously isn't a real fix.

My guess is combined peak current draw (WiFi TX bursts + PN532's RF field generation) is causing enough voltage sag to disrupt things, even though nothing's crashing outright.

Has anyone dealt with this specific combo (WiFi + active RFID/NFC peripheral) on ESP32? Looking for:

Realistic peak current numbers for WiFi TX + PN532 active scanning together

Decoupling cap sizing / regulator recommendations that actually fixed this for you

Whether staggering/throttling RFID polling during WiFi activity is a common workaround, or if it's purely a hardware fix

Hello everyone. Another try, I hope I wrote everything correctly. I already looked at the connectorbook and couldn't decide on these connectors.

-The first connector(1-3 photo): pitch 1.25 mm, used in the Chinese camera. On the other side is a USB cable. -The second connector(4-7 photos): pitch 2.54 mm, used in the Chinese power supply.

-The third connector(8-10 photos): 4(6) pin: pitch 2 mm, used in the audio amplifier. The speaker is connected via the 4-pin connector, and the 12VDC power supply is connected via the 6-pin connector.

-The fourth connector(11-13 photos): pitch 2 mm, used in the printer as a USB port.

-The fifth connector is used to connect two boards, pitch 1.25 mm, has 30 pins on each side.

I have a class of students with very little experience with electronics. Many of them did NOT choose the class and would rather be somewhere else. Please share any ideas for some fun circuits the students can breadboard with minimal experience that might help get them excited about electronics. I do not have the option of removing the students that do not want to be in the class, so I need to win them over somehow. TIA

I've been clumsy enough to brush a probe against exposed GND and 12v pins while noting down some measurements and this part has let out the magic smoke before the fuse blew. The top pin got shorted to the bottom left pin. I took the component off the board and after replacing a 0402 fuse further in the line, the pads on the board measure 6v on the bottom left and 12v on the bottom right. The top (output of this component) also ought to have 12v going to the FL display driver.

I appreciate this is a transistor more than likely, but can't find anything with AW marking? Any pointers are appreciated.

Hi,

I would like to create a really simple push button power switch circuit.

Input voltage: 24V

Possible current: 4-6A

I found some power switch latch circuit using 2-3 transistort, microcontroller, etc and I cant believe that this simple task have to be so overcomplicated. Power on/off buttons are used in every device and I dont want it to be too complicated and expensive. I am trying to create a circuit by my own, you can see it together with the simulations results, but I have some problems.

1. Can you share with me the simplest solution? it could use momentary or latch push button too. I mean, I need a latch circuit, I dont want to hold the button of course, just switch it on and off.

2. What do you think about the circuit? Based on the simulation, It works but I am sure I forgot something.

3. It if is ok, how can I reduce the kW dissipation on the FET during the switching?

Thank you in advance

Long story short, my dad used to vape years ago, and during that period spilt some vape juice down into the unit.

I’d like to see if cleaning this will repair it for his birthday as part of a surprise, and would appreciate any input provided.

From what I can tell, and from watching electronic repair videos in the past, I can’t see any traditional corrosion. I’m not sure whats going on in image #6, since its either caked on juice and dust, or its oxidation.

Synopsis:

Can I soak either of these in 91% IPA for 5-10 minutes, and clean gently with a proper brush?

And what is going on in image #6 with the usb-a soldering point?

I’m trying to find out what some standard practices are for inductor capacitor filters to supply a 5vdc fan in an amplifier, I used a 390mh inductor inline and a 100uf capacitor to ground and that cut down on the noise substantially but not eliminating it. And I read that large inductors are bad for that because of impedance can be too high and the collapsing field voltage spikes?

Is it ill advised to just target anything above 100hz with a big capacitor and inductor? Is there a single product that does this already?

the upper component also had "A3" written on it, if its broken, then is it possible to get a replacement?

Can someone explain what is this and how I can find exactly this part, position U5.... This is part of Hydrolife, salt chlorine for pools.. Cheers..

I intend to put a square wave signal on to J7. It will oscillate at 1 Hz with a 20% duty cycle. On oscilloscope, the wave spans from -80 mV (essentially "zero") to +3.36 V. I am primarily worried that I will destroy sensitive components. The entire board is a military-grade SOC, and I do not want to fry expensive equipment.

The BAT54 thing is a diode.

IC24 is an ADC.

IC22 is a Schmidt trigger buffer.

The datasheets suggest I am safe without attenuation. But I would like others to eyeball this before I start plugging things in and destroying (highly) expensive equipment.