writeup – The Salted Fish

Roland SR-JV80 Re-writable ROM Card with ESP32

January 28, 2025August 4, 2025 by ddzheng

For user manual and purchasing please visit: https://www.ddzheng.cc/?page_id=666 Final Update Open-source Hardware Hardware Repo: https://github.com/connorzheng97/srjv Firmware Repo: https://github.com/connorzheng97/srjv-fw Production Test For production test I have a contractor made a test fixture which probe the production header footprint from top side. The card is placed upside down in the fixture, a small board with mating expansion ... Read More

Korg Triton Repair and Restoration

November 17, 2024December 20, 2024 by ddzheng

A long time viewer of my Bilibili channel contacted me to do a restoration of his Korg Triton.

Tektronix DPO71254B Repair

September 11, 2024February 6, 2025 by ddzheng

There is a DPO71254B at my workplace that has been abandoned for quite a while. I repaired it so that we can use it to debug (no cal though)

Roland D-50 Repair

December 31, 2023February 6, 2025 by ddzheng

The long journey of restoring a Roland D-50

Oscilloscope Measurement Artifacts 1

December 20, 2023December 21, 2023 by ddzheng

In this article I present some aspects that distort electrical signal measurement result, with focus on what happens in the scope itself after the signal has entered an oscilloscope.