battery pin data for testing Motorola XPR 7550e??
 

Hi. First post here.
I was looking for a little help with a Motorola XPR 7550e VHF two way radio. Not sure this really fits the forum topic, but was the closest I could find here. Anyway, I found it at a thrift shop for just a couple bucks. No charger and the battery doesn't seem to have a charge, unsurprisingly (DMM, checked the different contacts.) Before paying for a charger or even a new battery, I was hoping to see if the radio at least powers on. So after doing a number of searches, skimming through the service manual, and even looking for pics of the main circuit board to see if I could spot the common, I'm still stumped. I can not find any references to which contact is which, in order to manually try and feed it with the 7.4v needed.
Even if it's not specified somewhere like in a user or service manual, I'd think it shouldn't be too hard to find mention of the batteries contacts for/by someone trying to test them, but still haven't found any relevant posts.
Anyone familiar with this XPR 7000 line? Looks like a PMNN4491 Motorola MotoTRBO e Series IMPRES battery.

Thanks for reading,
D

No one knows, or I'm just not giving it enough time...?
At any rate, I went back to the battery and tried something else. Seeing as the voltage was dead anyway, I tried checking for resistance instead of voltage. I found with the contacts that go to the radio, the outer most ones (there is two of each, for three pairs) are directly connected to a contact on the back (the contacts for the charger). So at the moment I'm assuming that's the common. The other two contacts on the radio side, I can then assume the larger is positive and the smaller a sense line of some sort. Unless I hear from someone to the contrary, I think I'll get around to trying out the radio with 7.4v from my bench supply in that fashion in the next week or so. (the 'bench' supply is actually buried under the bench at the moment.) If anyone is curious, I'll report back if it works out... or if I let the magic smoke out.

Quick update and conclusion. Yes, the outer contacts did end up being the common connection. With 7.4v fed in that fashion I was able to power on and test the radio. I wasn't sure on power consumption so limited it to 200mA, which worked fine to run the radio handset, but it would reset every time I tried to transmit. Very likely just needed more power, but could be a fault. At any rate, the basic question is answered (by myself), so no need for followups and consider this subject closed.