Just like what happened to nctnico here(45#
https://www.eevblog.com/forum/testgear/advantest-r3477-9khz-to-13ghz-spectrum-analyzer/25/).About a week ago, my R3477 reported "self-check failure" when it was started up, and checking the diagnostics info showed the Digital IF board failed.After replacing a short circuit 22uf ceramic capacitor on -5v rail, I still got a"fail".Further inspection revealed that two of the five ceramic capacitors next to the clock shielding box were defective, resulting in the output of the 5V->3.3V converter being only 1.xV (however, all parameters were normal when the removed capacitor was tested with LCR
).The digital IF board returned to normal after replacement.But, yesterday, I got another "Digital IF board not found" error
. This time, it was a 22uf ceramic capacitor in the I-channel shielding box that short-circuited and burned the 5V rail fuse.I realized it seemed like a problem of poor capacitor manufacturing?!(like rifa) The capacitor failure rate is too high.So I decided to replace all this capacitors on the board (using 22uf/50V X7R 1812package to replace).