MFJ-554 Classroom Code Practice Oscillator repair
There is a saying, "the journey is as important as the destination", and it applies when learning CW (Morse Code) - having an enjoyable and smooth tone to listen to is key (pun!) to a positive learning experience, while hacking away and trying to gain proficiency.
My MFJ-554 yields a warm, pure sine wave tone, but stopped working correctly after what I surmise to be an electrostatic discharge (ESD) popped the input FET.
In this video, I open up the MFJ-554, troubleshoot the issue and effect a repair.
MFJ-554 user manual (no schematic is available): https://cdn.shopify.com/s/files/1/028...
73 de M0NJX (a.k.a. Queuerious Guy)