It's not nice to criticize when someone asks for help -- but you should have
learned in school that a dead battery means that a device will just sort of
lie there and do nothing.

Why the unit should work properly when being powered by the 5V from the USB
cable, but otherwise produce a buzz, is not clear. How does it work when
being powered by your car's battery (that is, the plug-in cable)?

It's almost certainly not the battery. As you point out, it's difficult to
replace SMDs. I would suggest sending it back to Garmin.

On Feb 7, 5:28*am, "William Sommerwerck"
wrote:
It's not nice to criticize when someone asks for help -- but you should have
learned in school that a dead battery means that a device will just sort of
lie there and do nothing.

Why the unit should work properly when being powered by the 5V from the USB
cable, but otherwise produce a buzz, is not clear. How does it work when
being powered by your car's battery (that is, the plug-in cable)?

It's almost certainly not the battery. As you point out, it's difficult to
replace SMDs. I would suggest sending it back to Garmin.

No, as I said, this problem occurs when plugged into DC power,
different DC power, and AC power. Only slightly baffled why buzzing
disappears completely when side USB port is plugged into computer but
no one seems to have any ideas on this.

Really not sure what to do ACTIVELY about it as it does work fine,
with new maps so long as you don't mind no sound and having to leave
it plugged in all the time. Replacement of a numerous year old unit on
Craigslist would cost a small amount of money compared to replacement
with a refurb at Garmin AND any repair is likely to be quite
intricate. Wouldn't mind replacing the battery at about ten bucks but
am not sure that it would even WORK, not to mention get rid of sound
issue. Theoretically if this unit is over 3-4 years old, the lithium
battery may be dead AND if it hasnt been charged for some time, the
voltage would have sunk to so low a level, - for a lengthy enough
period of time that even if it weren't, it surely now is!

To recap: Leave plug in earpiece output to cut off speaker and await
whole unit failure. Take out when sound actually needed. (look for
similar unit on Craigslist for five bucks with dead battery and no
accessories and see if my battery suddenly springs it to life!)

Sorry, FWIW, for the benefit of onlookers who dont know this unit, it
has TWO usb ports: One for power in the back and a separate data-only
port to plug it into the computer at the side. It buzzes until the
side usb port is connected to a computer, - it gives a splash-screen
and then as soon as the connection is recognised, the buzzing stops.

On Thu, 09 Feb 2012 10:12:31 -0800, Austen wrote:

Sorry, FWIW, for the benefit of onlookers who dont know this unit, it
has TWO usb ports: One for power in the back and a separate data-only
port to plug it into the computer at the side. It buzzes until the side
usb port is connected to a computer, - it gives a splash-screen and then
as soon as the connection is recognised, the buzzing stops.

Only caught a few of the posts in this thread, so if I'm too far off base
I apologise. Many of the cheap power supplies are half-wave (rectified
one way only instead of through a bridge. They rely on a capacitor to
modify the intermittent "DC" to a (sort of) constant voltage. It may be
that the design of the Nuvi has this capacitor within the body of the
unit, so that if this capacitor has gone down, the smoothing will be non-
existent. If the buzz is mains frequency this would support the
hypothesis. If you can find a good quality full wave power supply, and
this eliminates or markedly reduces the buzz, it would (almost) prove the
case.

Keith

keith wrote:
On Thu, 09 Feb 2012 10:12:31 -0800, Austen wrote:

Sorry, FWIW, for the benefit of onlookers who dont know this unit, it
has TWO usb ports: One for power in the back and a separate data-only
port to plug it into the computer at the side. It buzzes until the
side usb port is connected to a computer, - it gives a splash-screen
and then as soon as the connection is recognised, the buzzing stops.

Only caught a few of the posts in this thread, so if I'm too far off
base I apologise. Many of the cheap power supplies are half-wave
(rectified one way only instead of through a bridge. They rely on a
capacitor to modify the intermittent "DC" to a (sort of) constant
voltage. It may be that the design of the Nuvi has this capacitor
within the body of the unit, so that if this capacitor has gone down,
the smoothing will be non- existent. If the buzz is mains frequency
this would support the hypothesis. If you can find a good quality
full wave power supply, and this eliminates or markedly reduces the
buzz, it would (almost) prove the case.

Keith

Surely all small low-voltage power supplies these days are switched-mode
with a tiny high-frequency transformer. This transformer provides isolation
of output vs input circuits, allowing use of a bridge. Using a bridge
rectifier at the supply input reduces the size of the smoothing capacitor
needed there to keep the switching running throughout the AC cycle.
Virtually no mains-frequency should get to the DC output. And if it did it
is usually described as a hum (even for US 60Hz) rather than a "buzz"...

Mike.
--
If reply address is (invalid), remove spurious "@"
and substitute "plus" for +.

On Thu, 9 Feb 2012 10:12:31 -0800 (PST), Austen
put finger to keyboard and composed:

Sorry, FWIW, for the benefit of onlookers who dont know this unit, it
has TWO usb ports: One for power in the back and a separate data-only
port to plug it into the computer at the side. It buzzes until the
side usb port is connected to a computer, - it gives a splash-screen
and then as soon as the connection is recognised, the buzzing stops.

I'm confused.

According to the following guide, one of the three options for
charging the battery is to "connect the AC adapter to a wall outlet
and the mini-USB connector on the side of the nuvi".

http://www8.garmin.com/manuals/Nuvi3...renceGuide.pdf

A second way is to "connect the USB cable to the nuvi and your
computer".

The guide does not mention two USB ports.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On 2/09/2012, Franc Zabkar posted:
On Thu, 9 Feb 2012 10:12:31 -0800 (PST), Austen
put finger to keyboard and composed:

Sorry, FWIW, for the benefit of onlookers who dont know this unit, it
has TWO usb ports: One for power in the back and a separate data-only
port to plug it into the computer at the side. It buzzes until the
side usb port is connected to a computer, - it gives a splash-screen
and then as soon as the connection is recognised, the buzzing stops.

I'm confused.

According to the following guide, one of the three options for
charging the battery is to "connect the AC adapter to a wall outlet
and the mini-USB connector on the side of the nuvi".

http://www8.garmin.com/manuals/Nuvi3...renceGuide.pdf

A second way is to "connect the USB cable to the nuvi and your
computer".

The guide does not mention two USB ports.

- Franc Zabkar

There's a USB port on the GPS unit and there's a USB port on the car
dock. When you use the GPS in the car, the power cord plugs into the
dock, and the dock has some pins that engage pads on the unit to
transfer power to it.

--
Gene E. Bloch (Stumbling Bloch)

Mine plugs directly from the DC cord & it is a flat connector, not USB. That
is how I deliver power to the unit. The true USB port is only used when I
connect it to a computer. I have mine mounted on my motorcycle, bypassing
the stand it came with.

"Gene E. Bloch" wrote in message ...

On 2/09/2012, Franc Zabkar posted:
On Thu, 9 Feb 2012 10:12:31 -0800 (PST), Austen
put finger to keyboard and composed:

Sorry, FWIW, for the benefit of onlookers who dont know this unit, it
has TWO usb ports: One for power in the back and a separate data-only
port to plug it into the computer at the side. It buzzes until the
side usb port is connected to a computer, - it gives a splash-screen
and then as soon as the connection is recognised, the buzzing stops.

I'm confused.

According to the following guide, one of the three options for
charging the battery is to "connect the AC adapter to a wall outlet
and the mini-USB connector on the side of the nuvi".

http://www8.garmin.com/manuals/Nuvi3...renceGuide.pdf

A second way is to "connect the USB cable to the nuvi and your
computer".

The guide does not mention two USB ports.

- Franc Zabkar

There's a USB port on the GPS unit and there's a USB port on the car
dock. When you use the GPS in the car, the power cord plugs into the
dock, and the dock has some pins that engage pads on the unit to
transfer power to it.

--
Gene E. Bloch (Stumbling Bloch)

On Fri, 10 Feb 2012 14:50:05 -0800, "Scott W"
put finger to keyboard and composed:

Mine plugs directly from the DC cord & it is a flat connector, not USB. That
is how I deliver power to the unit. The true USB port is only used when I
connect it to a computer. I have mine mounted on my motorcycle, bypassing
the stand it came with.

AIUI, the GPS can be powered and charged either via the side mini-USB
connector or via the rear DC power socket (wherever that is).

If an adapter, either AC or DC, is plugged into the rear, then the
unit buzzes. OTOH, if the mini-USB connector is used, then there is no
buzzing. This suggests to me that, if two power sources are connected
to the unit at the same time, then the side port takes precedence. It
probably disables the rear port, which would explain why the buzzing
goes away.

One thing still bothers me, though. The OP states that the AC adapter
plugs into the rear port, yet you are saying that this is not a USB
port. The guide, OTOH, refers to the AC adapter as a standard
inclusion with the nuvi 350, so presumably it has a micro-USB plug
(???).

One other thing that may be worth considering is the current draw. A
computer's USB 2.0 port is current limited to 500mA, so this would
place a limit on the charging current via the side port, at least when
the GPS senses a USB host controller. AIUI, USB OTG (on the go)
specifies a signalling system that enables a device to draw a greater
current when it senses a charger. Maybe that could account for the
difference in behaviour.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.