I got a 720 yesterday. It was working without any problem until I plugged it into the PC and couldn't get a USB connection to work. I tried another PC, same issue. I opened it up to have a quick look and plugged it in while apart and the USB started working . While it was connected I tried to load 9.051se into it, the same as I use on my 730.

It was at this point that the touch screen stopped working completely

I've tried swapping the screen with the 730 and both screens work when attached to the 730, but neither work on the 720.

I've tried loading the original navcore back onto it and still no touch.

Does anyone have any ideas?

Thank you!

Hi,

It sounds as though the unit is freezing rather than the screen being faulty in some way (since it works in the 730) - have you tried a hard reset?

I have seen this occur when the navcore has become corrupt (which might indicate an internal memory problem).

There are other possible causes: damaged pcb from a bodged USB connector repair for example or improper dis-assembly or assembly of the unit - You have only just 'got' it - do you know it's history? Could there have been a repair in it's past? Is the battery at the end of it's life? Are there signs of manual soldering on the pcb/connector? Could you get your money back from the seller? I am being a bit of a devil's advocate here - bear with me, but these are all questions that you need to consider because it is not the change of navcore that is causing it. One glimmer of hope is that on one occasion, a hard reset brought the touchscreen back to life, although I have to add that it died again 2 days later, never to recover.

Macca

mpdaws wrote:I got a 720 yesterday.
1. It was working without any problem until I plugged it into the PC and couldn't get a USB connection to work. I tried another PC, same issue.
2. I opened it up to have a quick look and plugged it in while apart and the USB started working . While it was connected I tried to load 9.051se into it, the same as I use on my 730.

It was at this point that the touch screen stopped working completely

I've tried swapping the screen with the 730 and both screens work when attached to the 730, but neither work on the 720.

I've tried loading the original navcore back onto it and still no touch.

Does anyone have any ideas?

Thank you!

1. This is a common issue, if a unit is disconnected incorrectly from a computer.
2. This is the absolutely last thing to do.
3. Have you tried a "hard reset"?

Macca-009 wrote:Hi,

Hi,
It sounds very much like the pcb of the 720 has become partially detached from the USB connector at some time (or vice versa if you prefer) - it is not unknown for bodged repairs of loose USB connectors to cause all sorts of problems. You have only just 'got' it - do you know it's history? Could there have been such a repair in it's past? Are there signs of manual soldering on the pcb/connector? Are you confident and/or competent with a low wattage miniature soldering iron yourself? (thinking that it may need to be re-fitted) Are you competent at repairing damaged pcb tracks? Could you get your money back from the seller? I am being a bit of a devil's advocate here - bear with me, but these are all questions that you need to consider because it has nothing to do with software/navcores. It is also possible that a component on the pcb has been shorted or damaged, but it will almost certainly be related to or adjacent to, the usb connector or the attempted repair of it.

Macca

I don't see it as being a USB problem based on mpdaws last statement: "I've tried loading the original navcore back onto it and still no touch". To do this requires a unit USB connection, unless he is loading a SD card in a card reader.

Thanks for your thoughts so far.

I don't think the unit has had any physical repairs. The PCB and certainly the USB connector looks pristine and identical to the 730. I'm just working with the internal memory on this one, no SD card.

I don't think its freezing because it gets to the 'select a language' screen which keeps scrolling through the language options. If it was freezing I would expect that it wouldn't be scrolling though the languages. Also, if I plug it into the PC it instantly pops up the question about connecting to the PC. I just can't select a response to any of the questions that it's asking.

I've tried a few hard resets and using the clear flash tool.

You're quite right about not knowing the history of the unit and I went into the purchase knowing that this could end up being a spare parts unit, but I'd like to have a good attempt at making it useful.

It is possible that there is a corruption of the internal memory. I've seen it written on the forums that you shouldn't format the unit, but I'd like to do some testing that will destroy the file system. Is there any instructions on how to correctly format it again once I've done the testing?

Thank you!

mpdaws wrote:Is there any instructions on how to correctly format it again once I've done the testing?

You're obviously aware that the guys here on Navitotal don't recommend formatting - in fact I don't either - but if you go down that route, I believe that TT say the correct file system to use is FAT32.

Macca

mpdaws wrote:It is possible that there is a corruption of the internal memory. I've seen it written on the forums that you shouldn't format the unit, but I'd like to do some testing that will destroy the file system. Is there any instructions on how to correctly format it again once I've done the testing?

A corrupted internal memory will not affect the touch screen. Formating will not affect the RAM memory.