Rig dead after trying to update firmware

[Pugsley]

I had a working rig, but wanted to change the call sign, so I downloaded the firmware and flashed it. It came back up with new call sign, but was unstable, screen getting corrupted and went downhill from there. After a couple of restarts now it is showing a big long number across the screen that is not the serial number that came with the rig new. Now when I try to reflash the firmware it says:

Error: programmer is not responding
Warning: attempt 10 of 10: not in sync: resp=0x00
Error: unable to open port COM7 for programmer arduino

Tried both AVRdudes & Xloader.

This rig is a couple of years old, ver 1 lo bands, bought from UpTech with bootloader installed. It will now only power up with USB port, if I try from barrel jack, nothing happens despite having 11.6v on the SIP header, even with mainboard only, no RF board attached.

Is there anyway to fix this at this point?

[DL2MAN]

WIth the different behavior between USB and 12V SUpply, it is very likely, that something is shorting 12V Line.
Most likely candidates are 3 BS170s on RF Board.
Try updating firmware only with mainboard connected and check if maiboard works,
If yes: Probably BS170s
If no: Check 7805 and big tantalum caps for shorts.

And yes: Every (tr)uSDX can be repaired. That´s why I started a series on youtube about troubleshooting.
It´s a simple design and can be fixed easily with a soldering iron and some logic applied.
If you yourself are not able, ask within your local HAM club.There are always Elmers, that will help you.

73 Manuel; DL2MAN

[Pugsley]

Thanks for the tips. The mainboard will not power up with 12v in even without the RF board attached. C2 measures over 200k ohms and C4 measures over 12k ohms. With 11.6vdc in it is getting to the input of the 7805, but it is only putting out 2.2v. The only way I can get the screen display anything is with USB power in.

[DL2MAN]

Something is pulling down your 5V line, when 12V is present.
When you apply USB Power is 5V Line 5V then ?
If so, you might want to look into reverse polarity protection diode for defect (D5) and Polyfuse (F1) for misbehavior when "normal" current is present.

[Pugsley]

Thanks for the reply. Yes, when I apply USB power, the 5V line is 5V. I have looked all over this mainboard and cannot find D5 or F1, this is a version 1.0, are these devices not marked or different on my board? I do not see them on the schematic either. I did test D3 & D4, they both test good.

[DL2MAN]

OK then:
Ver 1.0 doesn´t have those parts.
Then the good news is it can only be one of those parts:

12VIN.JPG (42.38 KiB) Viewed 278 times

Most likely C2,C4 or U2 (in that order)

[DL2MAN]

Uhm:
ANother thought: What power supply do you use ? Does it provide enough current ?

[Pugsley]

I will check this first chance I get, can those caps be checked in circuit ok? I use a Talentcell 12V battery pack, it runs a QMX quite well.

[Pugsley]

C2 & C4 are both well under 1uf each as measured in circuit and U2 is 11.4V in & 2.2V out.

[DL2MAN]

It´s not about Capacitance but DC bahavior: Can you measure a short or low resistance to GND ?
If in doubt: Swap them anyway.
Eletrolytic caps have weird failure modes.....

73 Manuel; DL2MAN

[Pugsley]

That is interesting. C4 measures about 210k ohms no matter which way I have the test probes attached. C2 measure about 210k ohms one direction, but when I reverse the the test probes it is a much larger, but unstable measurement, mega ohms.