EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: bd139 on November 17, 2017, 07:24:51 am

Title: HP E3630A buzz - preregulator or transformer?
Post by: bd139 on November 17, 2017, 07:24:51 am

Got myself an HP branded E3630A dated around 1999 the other day and it’s buzzing at 50Hz when not under load. I know the preregulator on early units is a bit wonky on these as there’s a missing pull up. Is there any way to isolate this or the transformer conclusively. Not a problem if it does buzz, but would rather fix it if it’s the preregulator as this has some other side effects.