First of all, your bail on the new case is unrelated to the probation case. You will be eligible to get it back if you pay it and appear as ordered for court hearings. You do not have to make bail before you get violated; the probation officer can violate you and have you transferred from the jail you're being held in for a hearing. The probation officer likely has a lot of discretion about when (or whether) to violate you, but he likely has to do it within a reasonable time of finding out about your new charge. I don't know if Maine's rules prescribe a certain time period for issuing a surrender notice. Your best bet might be to call your probation officer and talk to him/her about what his intentions are -- most will be up front with you about what they're going to do, and sometimes talking to them helps. Otherwise you should contact a criminal defense attorney to represent you; the attorney can speak to your PO on your behalf.
The other answer is not exactly what you should be looking at. In Maine, the probation officer will not violate you in most cases, until you post bail on the older charge. There will be a bail hold on you, so you need to post bail and then be violated and post bail a second time. However, you do get all your bail money back assuming you show up for court and eventually take care of the pending and older case. In Maine, the judge will also review both the old charge and the newest charge, and post a new bail which will allow you to get out, assuming you are not a public safety threat and have no history of defaults. The probation people will work with your lawyer and the judge and the DA to get you released on terms that assure you will be in court and not a problem if released. So, the answer is, if you never post bail on the first charge, the probation officer has no reason to violate you, since you are serving time and in jail. You should immediately request a court appointed attorney or hire your own attorney.