Early in 2018, I purchased an HP 3562A Dynamic Signal Analyzer for an excellent price on Ebay. The display looked great and it was physically in good condition. However, the unit failed the power on self test as follows:

HP 3562A Error Message on boot

This error code indicates a ROM IC failure.

HP3562A Diagnostic LED’s indicate Hex code 4 4 (0100 0100)

This code indicates a failure of ROM Chip U105:

HP 3562A Rev B ROM board. The problem ROM chip is the fifth chip down in first column (U105)

HP 3562A ROM Board Rev B

This ROM board is an older version using 32kx8 chips in two groups (Low Byte & High Byte) of 18 chips each. I had access to a second 3562A, and swapping ROM boards confirmed that the ROM board was the problem. Now I needed to:

Locate a suitable set … Read More »