I've read many of the threads about this. I have an old PMB-648 and it will not sync. The unit has a solid 5 volts, close to 5.22 if the meter is trusted. Its been outside for about 25 minutes and is still flashing. The device used to work well. Its been off for a couple of years since it was used. Is there any reason (age?) that would prevent it from working. I have it outside for a prolonged period of time because someone posted that the sats have to download if it is viewed as a first time connect. And at this age, and inactivity, I am sure that is a possibility.
Thanks in advance for any info provided.