After failing to fully cure the wobbly display on one of my VT320s (Thread) I have decided enough time was wasted fiddling with the old, overcooked PCB.
I have tried replacing the main DC/DC covnerter IC, as well as several capacitors, but the display still had a small, annoying, noticeable horizontal wobble.
So I have designed and built a replacement power supply board for the VT320.
All the production files have been placed on github.
This board is a drop-in replacement for the DEC 50-17278-01 board that supplies +5V, +12V and +18.5V to the main VT320 board.
It is based on off-the-shelf parts (mainly Astrodyne TDI board-mount power modules) that total under $60 in small quantities.
My replacement board supplies +18V instead of the original +18.5V, which seems to work just fine.
Note that, at least according to available schematics, there were two versions (pinouts) of the DC power connector. I have designed the board according to the terminal that I needed to fix. But a different-pinout VT320 can easily be changed to connect to my new board by replacing the order of pins on the female connector. All is needed is a small flat head screwdriver.
