New Members
Please consider donating to this site if it has helped you. We rely on these donations.
Please also introduce yourself here Introduce yourself here.
And finally, Read the Forum rules here.
I have an old analog voltmeter that can correctly measure DC voltage between 0v to 3v. The voltmeter is made by Toyokeiki depicted in the photos. It does not need any battery. It works using a coil and a magnet as any other analog voltmeters.
I am going to convert this voltmeter into a DC ammeter that can measure DC current between 0A to 15A.
To do this, I use a 0.2 Ohm resistor for current sensing in the circuit. Then, I use the setup depicted in the photo to measure current.
For example, if the power be 12v and the load be 8 ohms, the voltmeter shows...
A friend recently gave me an old analog Heathkit IM-5238 AC Voltmeter that he'd had for decades. It is in very good condition, but I very rarely work with AC equipment and I already have an old Fluke 75 DMM that another friend gave me several years ago. I use the Fluke constantly. I mainly repair vintage PC components and boards. Once in a while I do some work the audio equipment but it isn't my area of expertise.
Does the analog AC Voltmeter offer any practical benefits over the little Fluke 75? It is very large and very specialized (as opposed to a DMM that can test many different...
I have had this old bench power supply which I have decided to look into repairing. I have no idea where it came from.
Attached is a picture. I cannot find much information on it to even figure out what it is rated for. The analog display goes to 25V, but the voltage regulator chip is rated for 5V (UA7805 - KC - F 8221 - Korea). The cap is rated a 100uf 50V. There is noting on the bottom but some traces. Pretty much what is seen is what is there.
Optimized Multi-Phase PWM Controller
with 6-Bit DAC for VR10.X Application
The ISL6556A controls microprocessor core voltage
regulation by driving up to 4 synchronous-rectified buck
channels in parallel. Multi-phase buck converter architecture
uses interleaved timing to multiply channel ripple frequency
and reduce input and output ripple currents. Lower ripple
results in fewer components, lower component cost, reduced
power dissipation, and smaller implementation...
Hello,
I have MacBook Pro 2022 M2 with MB 820-02773 and it is completely dead. When I plug USB thru USB Voltmeter (FNB58), the Voltmeter turns off. I don't have any voltage on any pin. Looks like undetected. Should I replace UF100 and UF000 first? I don't have any idea how to start repair without voltage. There is no water damage or visually broken components.