sp50 low battery alert

[rickb]

I have a sp50 that produces a low battery alert even when operated from a 7.5 v dc supply. The bat contacts are good, switch is ok, on board regulators are in spec and the pick off point for the a/d battery check is ok. Even if I raise the ps to 12 v, it still says low bat. I have had several of these go across the bench and have never solved it. For uncritical environments where the user did not want to pay for mot repair, I turned off the audio alert. Others just put up with it. Comments?

Rick

[Bat2way]

There's a good post a little while back which describes this in some detail. Check R421, R422, and CR404. I believe that's the parts off U401-13 that sense the voltage. Maybe cold soldered or cracked, or there is some defect in the layers or micro for that function.

[rickb]

I have searched quite a bit for it. Do you recall any search terms that are unique to that thread?

Rick