Blog Joshua

Another soldering iron repair.

It happened again, the exact same problem as before.

Salvaging 18650 li-ion cells from dead battery pack of a ThinkPad T530.

I modified the scale of a digital panel voltmeter to make it show value 10 times the actual measured value.

Pedestal fan repair by replacing the entire AC motor assembly.

I have completed my build of Jay_Diddy_B’s 7 Transistor ESR Meter.

I made this list after reading The Small Website Discoverability Crisis.

Repair of the electronics inside a toy macro lens.

The pads were there, so why not add a switch to WD2002SJ board?

Repair of a WD2002SJ board (LTC3780-based buck-boost converter).

Designing and building a dumb charger with battery reverse polarity protection.

Expensive battery just begs to be tested.

A LM317 circuit with 6V DC output as intermediary between an unregulated wall wart and my speakers.

Failed repair of a salvaged MikroTik RouterBOARD 750GL.

I repaired a pair of salvaged speakers.

I just got a new portable rework station.

Testing a PAM8403 Class-D amplifier module with a pair of salvaged speaker drivers

Assembling calibration resistors for the ESR Meter.

Salvaging 18650 li-ion cells from dead battery pack of a laptop.

Broken LED bulb repaired.

I have completed a XR2206 function generator kit build.

Happy New Year 2023.

I have completed my build of Jay_Diddy_B’s 5 Transistor ESR Meter.

I just got a new power supply.

Transferring the digital clock circuit to a perfboard and putting it into an enclosure.

Sleep mode and Schmitt trigger on multiplexed analog buttons.

Broken OLED color screen on Quicko T12-952 now replaced with generic 128x64 I²C monochrome OLED.

Broken OLED color screen on Quicko T12-952 can be replaced with generic 128x32 I²C monochrome OLED.

Happy New Year 2022.

Hello, my name is Joshua Rocky Tuahta Purba.

Replacing Arduino Nano with regulatorless Arduino Pro Mini.

I cut off the voltage regulator from the Pro Mini board.

Arduino Pro Mini clone’s regulator fried when connected with 12V power supply.

Arduino Pro Mini tryout with 128x32 I²C OLED display.

Adding buttons, alarm buzzer, temperature and humidity sensor, brightness potentiometer, and menu system.

Transferring the circuit to a bigger breadboard.

Adding the LCD display for the Arduino-based digital clock.

I want to make a digital clock.

Practicing to crimp open barrel terminals.

A tool to test devices for short circuit or big inrush current.

My previous post about the Mystery Transformers wrongly assumed which ones were the primary and secondary windings.

I bought two used transformers.

I have decided to create this new blog.