Dynaco Pre-amp Repair in Chicago?

The power on my Dynaco tube pre-amp keeps going on and off (I sometimes have to move the pre-amp just to get the power on). Once it is on, it generally stays on. Any ideas on what might be causing this? Does anyone know a reputable audio shop in the Chicago area that I can bring it to?

Hi Roger, you might speak with Ned at Triode Electronics, as he has worked on Stereo 70s and such for years. If needed, contact me offline and I'll put you in touch with someone in our area who may be able to help. Good luck!
Hi, One place I would highly NOT recommend in Chicago, would be Martroy Electronics. While I have no doubts they can fix it, they'll also take you to the cleaners on the cost. They've done it to me, and another friend of mine. Try $60 to replace a AC Cord on a Scott Tuner for myself, and $200 to lamp a Sansui 8080 reciever for a friend! Avoid this place like the plague! Mark