View source for Android g1 will charge but not mount

I have two G1 phones that have been working for over a year but simultaneously started to exhibit a problem with charging and mounting.

Neither would charge in the chargers that had been working for months.  After swapping cables and chargers, I found a configuration that would work for each phone and they could charge again.  But then I couldn't get them to mount when connected to a computer.  The phone would be charging, but the "USB connected" status icon would not show up so I could use it to ask to mount the phone.  Also, looking at the computer's log, it did not show any USB device connected.

Googling for the problem found it to be wide-spread but not particularly related to a common event like a recent system update.  One person called tech support in UK with this problem and was told that using different chargers could confuse the sd card and was sent a free replacement card.

Having already tried all the combinations of cables and computers that I have access to, I opted for this procedure:

* unmount SD card in Settings
* turn off phone
* reseat SD card
* reseat SIM card
* reseat battery
* turn on phone

It worked.  I'm glad I didn't have to resort to a factory reset.

=== Not entirely fixed===
My phone isn't reliably noticing when a USB cable is attached.  It is now behaving like there is a loose connection in the phone's USB port.  But it sometimes gains or loses the connection even when the phone is not touched or moved.  Weird.