Mike, the computer is about 2 years old. I just started to use sleep/hibernate to get around a long start time. Hibernate is fine, but not as fast coming up as the hybrid sleep. A couple nights ago, I put the PC to sleep and then turned on an AM radio and found the interference blotting out a favorite AM station at 900 KHz. Tuning the radio, I found the interference over range of frequencies with a peak at 890 KHz which swamped my 900 KHz station. Brought up the PC again - no interference. Hibernated the PC - no interference. I repeated this about four times with same result every time.
The case has not been opened for many months. I will try un/replugging all external cables.
No BIOS changes in many months. But then I didn't sleep the machine, so the problem could have been around for a long time.
I did discover one more thing. Driving into my driveway and into the garage, my radio tuned to 1290 KHz was totally swamped by the same sort of interference. And yes, I'd left the PC in sleep mode. This opens a couple possibilities, the most likely is radiation from my house wiring. I have some RF filters that I'll place on the PC power cord. More after I try this idea.
Update 1: I put RF chokes all over. I pulled and reseated all cables into the main case. No change. But I did notice one thing. I have three USB3 attached hard drives. By watching the lights and listening to the AM radio, I seemed to see and hear a correlation between the two. Which gives me the idea that external hard drives might be, in part, the source of the EMI. I'll explore this and report back with an update.
Update 2: Hard drives are not the problem. With all 3 disconnected, the problem remained. The EMI, monitored on a portable radio, was different with and without the 3 drives connected. It reached its peak at the moment the power button turned orange and the pulsing began, and continued.
It appears the best thing is not to use sleep mode when I want to listen to my radio. Or maybe just use hibernate all the time.
I'm still open to new ideas.
...Charlie
Facebook
Twitter
Instagram