high pitched hum on mic

[adapter pilot]

I know someone had a problem with a high pitched hum on the outs but mine seems to have this problem with the built in mic. When I record from the mic the hum is pretty loud. I don't have the power supply-so it might just be that
Anyone have this problem when running on batteries? Does the power supply correct it?
Any fix?

[xdemalaga]

I think I have this same problem on my sp202, I can run some experiments tonight.
do you mean using the mic to record sounds from the room, or the mic-in ?

i suppose the different variables to test would be:
rca in vs mic in vs built-in mic recording live sound
battery power vs power supply
live out vs headphone out
hi-fi mode vs standard mode vs lo-fi mode 1 vs lo-fi mode 2

any others i'm missing?

[adapter pilot]

It's just the built in mic-the rca ins are fine. I'm going to try the 1/4 in as well. I haven't used it in a long time so I'm not sure if it has the same problem. I have a 9v power supply but it's 400ma and the 202 is 200ma-I'm not clear on the ma stuff so I don't want to fry it. Thanks for the help.

[adapter pilot]

solved. It's just hi-fi mode. Fine in other modes.