Latching on/off circuit question

Design Concepts
1

Hi,

I’m getting ready to mount a new MIDImon in an enclosure and had hoped to re-use the existing momentary tact switch to power it off and on.

I found and tested a transistor circuit from here-

http://www.edn.com/article/CA472837.html

It works OK, but it powers up in the “on” state, which I don’t believe it’s supposed to do. I’m running with a 12V supply (dropped to 5 by the regulator), and my resistor values came out to: R1-  10M, R2-  470k, R3-  2.3M, R4-    1k, R5-   50k, R6-  2.3M, R7-  5M, R8-  500k, R9-   5K. I was using BC 547’s and 557’s for the transistors. I was also only using an LED for the test load. Hopefully, the switch will function the same with the PIC, etc.

I’ll probably throw a 120VAC DPDT slide on the back to kill the power to the transformer completely.

Does all this sound like a reasonable on/off setup for this, before I commit it to copper?

Also, would inserting such a circuit after the filtered 7805 output pose any problems for the PIC circuit or ruin my nice, clean supply?

And lastly, does anyone with a better understanding of transistors or this switch circuit know why it would be starting off latched, and what to change?

                           -Thanks!

                                        George

BTW- The 10M resistor at R1 started at 2.3M, but it would switch back on if you held the button for a second while turning it off.