Atari 400 correct power supply

[shear_xear]

Hi everyone.  So I have an Atari 400 with a C017945 power supply, and I am getting what looks like interference on the screen, similar to what I have seen when the amps are off on a power supply.  I thought that this was the correct power supply for the 400.  Is that wrong?  Thanks!

[+DrVenkman]

That should be the correct part number. Do you have a way to measure the output voltage? It's a 9VAC adapter, but without a load on it, it will give you a reading of like 10.5 - 11.5VAC, which is perfectly normal. These are dead-simple devices, just AC transfomers, so there's very little to go wrong with them. 

 

The stock Atari 400 lacks a direct composite video connection, so you'll be using RF to a switchbox or a screw-on coax adapter, correct? Chances are, what you're seeing is noise in the RF signal from a bad connection or some other local interference. If you're using a switchbox, that's probably the source of much of the noise. If not, you could have a bad cable, or one of several other things.

[shear_xear]

Thanks for the pointers!  I will check it out with my multimeter.