FT-991 COM issue

[VK7HH]

Hi All,
My FT-991 has recently developed a COM port issue. When plugging in the USB cable to a PC the COM ports no longer show (Standard and Enhanced). 
The USB audio still shows up correctly. 

I've uninstalled/reinstalled the relevant drivers, rebooted the PC, tried a 2nd PC and even did a full reset of the radio. So scratching my head why it's not working all of a sudden. Has anyone got any ideas on how to fix this peculiar issue. Up until today it had been working fine.

[VK2ZIW]

Hayden, are you running Linux?

There were stories of windoze drivers reloading the firmware into COM port devices and killing it
if it wasn't genuine. That's a bummer if it's the COM port inside a radio.

1st I'd try a Linux box.

AND always use a Linux box as Linux NEVER reloads firmware like this.

The new mode JS8Call is a hoot.

Alan VK2ZIW

[VK2CSW]

How very 1990's of you.

A genuine OS Bigot. I was sure they were all in museums now.



Do you really think that a driver for an OS can reflash a chip on a third party device? The issue you mention relates to Prolific USB chipsets. Newer Windows drivers from Prolific recognise fake chipsets and simply do not work with them. It is not Microsoft being a big bad spooky overlord, it is Prolific simply protecting their IP.

Now, I doubt Yaesu are using fake Prolific chipsets on board and as other machines are having the same issues on that radio, I don't think it is a driver issue.

However, what driver brand does Device Manager or it's equivalent say it is using?

If it has a Prolific chipset on board and you think it may be the Prolific issue, do a web search for the older drivers and temporarily install those and see if it springs back to life.

[VK4ADC]

I'm guessing the first question that should have been asked is " did you unplug / re-plug anything around your radio gear between when it last worked and when it no longer worked ?"  
That includes port leads, even loose power leads, antenna leads.  Anything that could cause static charge destruction of the FT-991 serial port hardware ?

Did Win do an automatic update in between those times ?  
Do a history lookup and a roll-back to an earlier date if needed to confirm any un-obvious side-effects..

If it doesn't work on a different PC, regardless of operating system, then it is either in the interconnection lead or the radio itself.

Just an anecdote on a different brand, an Icom 7400, that lost serial CIV control.  Turned out to be an O/C SMD choke between the "ground" pin on the external CIV socket and the associated PCB main board earth plane had been fused somehow. (Must have lost a 12V supply earth lead somewhere along the line.) Replaced the SMD inductor & all serial comms went back to normal.

[VK2ZIW]

Colin, I'm NOT an OS biggot.

I run windows when it is necessary

Everything we do has risks. Even, plugging in USB devices.

Diagnostics here is the issue. I do not find it easy to get a simple listing of
all USB device IDs on Windows.

Under Linux (any flavour) the "lsusb" command will display all the devices and allow
one to then Google the device IDs for drivers etc..

a simple "ls /dev/ttyUSB*" will then display it's serial port name.

In defence of Yaesu and Icom etc. their purchasing departments don't always get it right
procuring parts for manufacture.

Consider the Samsung S2 and S3 phones with faulty EMMC.

It happens

Alan VK2ZIW

[VK7HH]

I'm guessing the first question that should have been asked is " did you unplug / re-plug anything around your radio gear between when it last worked and when it no longer worked ?"  
That includes port leads, even loose power leads, antenna leads.  Anything that could cause static charge destruction of the FT-991 serial port hardware ?

Did Win do an automatic update in between those times ?  
Do a history lookup and a roll-back to an earlier date if needed to confirm any un-obvious side-effects..

If it doesn't work on a different PC, regardless of operating system, then it is either in the interconnection lead or the radio itself.

Just an anecdote on a different brand, an Icom 7400, that lost serial CIV control.  Turned out to be an O/C SMD choke between the "ground" pin on the external CIV socket and the associated PCB main board earth plane had been fused somehow. (Must have lost a 12V supply earth lead somewhere along the line.) Replaced the SMD inductor & all serial comms went back to normal.

RE: Unplugging/replugging, no. I checked to see why WSPR wasn't transmitting anymore that is when I saw the rig control error on the PC. PC hasn't restarted and doesn't do auto updates anymore. 

I contacted someone today who looks after warranty repairs and they said they suspect a dead USB IC, but would like the radio to check. Luckily it's still in warranty.