Hi there, I experienced a failure on my TDS580D DSO.
The error logger reports the DAC2 Varigain DAC too high, and indeed the CH2 hybrid attenuator/preamplifier variable gain input is set to its maximum, and its output correctly is about 40% higher than what it should be.
I checked the CH2 attenuator/preamplifier anyways swapping it with CH3 and nothing changed, confirming that the attenuator/preamplifier is good.
Since the circuitry after the attenuator/preamplifier output is changed from the TDS520B schematics available on the Internet, I would like to know if someone out of here had any information about that circuitry.
In particular, I would like to know what is the name of the integrated circuit which seems to embed the sampling triggers logic and maybe the 4 ADCs which has the heatsink sticked on it.
I also would appreciate any information about the National semiconductor’s BGAs named MM9599-UCC.
Have a great day.
Massimo