I had a Peterson for YEARS (model 420 from way back in the early 70's) had to manually switch on the dial, just sold it on here a couple years ago for a little over $100 ... I dont think the built in mic worked, but it may have if you used an external mic in the 1/4" jack ... I missed it after a while and got a Turbo Tuner also ... for bench work I liked the Peterson set-up, front display, etc, but TT has been more than acceptable replacement ... and it fits in shoulder bag to go ...
Edit to add: .. for the heck of it, I just checked Ebay to see what is available and what they were getting for old Petersons ... there is a beat looking 420, and this 400 which is EXTREMELY clean one owner .. I thnk the only diff between 400 and my 420 was the built in mic on the 420. If I was using it strictly for bench work, I would really be tempted on this one, but with the Reserve, who knows what he needs for it ...
http://www.ebay.com/itm/Peterson-St...087?pt=Guitar_Accessories&hash=item418c861697