Strange SerOut Problem

[skimask]

Well by -5V, I mean the negative side of the power supply.
This is the power supply I'm using (pretty cheap and nasty, but I thought it would do the job (it did for a while)).
http://www.jaycar.com.au/productView...Max=&SUBCATID= - Model MP-3144 (the first one listed).
...I don't know what switchmode means...

Switchmode...hmmmm...maybe there's not enough load on the circuit to turn on the regulator in the PSU, which is sometimes needed for those things. I'd try a battery pack next, even a 9v battery with a 7805 will do for awhile.

P.S. - quick lesson in PSU's

Linear power supply - you put in 10v, you want to draw 5v @ 1 amp. The regulator dumps 5v @ 1 amp overboard as heat and saves the other 5v for your output. In this case, it's only 50% efficient.

Switchmode - you put in 10v, you want to draw 5v @ 1 amp. The 'switcher' basically turns a MOSFET on and off really fast (sometimes as high as a few Mhz) thru an inductor to keep an output cap charged up to 5v. Sometimes these types can hit about 98% efficiency, very little wasted heat. Drawbacks are that you have to draw a little bit to keep the regulator regulating and they introduce a little bit of noise on the output (a very little bit, usually not enough to mess with anything).