I am having problems with the power test and getting no VBUS volts when powered from USB.
Using Rev H PCB and schematic.
I started with only JP2 and all 5 BOBs installed. VBUS=0V
Checked physically for shorts under magnifying lamp then tested with meter. No shorts found.
Removed JP2 and no change.
Using meter across USB 5V and 0V rails for resistance and get >2KR one way and when 20R when probes reversed.
Removed BOB2 and no change.
Checked 5V available on micro USB connector when not plugged into DSO68 and get 5V
Checked VBUS when plugged back in and still = 0V
Checked continuity from USB plug (laptop end) through to FB1, D4 and one JP1 legend and okay.
Removed BOB1 and no change except:- Using meter across USB 5V and 0V rails for resistance and get >2KR one way and no change when probes reversed.
Checked again for shorts with meter on PCB checking the micro USB connector, FB1, D4, JP1, BOB 1 PCB connector pad and all micro USB connections; no shorts.
Laptop USB port works with light operated mouse.
I think that I have isolated shorts loading USB power supply as far as possible and still no VBUS 5V.
Checking schematic I cannot see any other use of VBUS and potential area for issue. Also there is no load so hopefully eliminated that as potential issue.
I have not tried using a battery.
I do have a external 9V PSU that I could use and fit a diode (1n4001) into D5 although wanted to seek advice first.
Please can you assist?
power up test no VBUS
Re: power up test no VBUS
Jonathon,
I am having a somewhat similar problem in that I have a good power supply section until I jumper j4. then my voltage goes to about 2.1 volts. when I disconnected the vin pin on bb 5 everything checks out again.
the only thing I have to offer is to do the same, disconnect the no. 1 pin on bob 5 and see if you get a stable power supply...sorry I don't have more to offer at this time, maybe when I get my problems solved?????
Norden, N7SOC
I am having a somewhat similar problem in that I have a good power supply section until I jumper j4. then my voltage goes to about 2.1 volts. when I disconnected the vin pin on bb 5 everything checks out again.
the only thing I have to offer is to do the same, disconnect the no. 1 pin on bob 5 and see if you get a stable power supply...sorry I don't have more to offer at this time, maybe when I get my problems solved?????
Norden, N7SOC
Re: power up test no VBUS
@ Jonathan:
VBUS is from USB through FB1. Did you check FB1? You can simply short FB1 if you find it broken. There will no impact to the scope without FB1.
VBUS is from USB through FB1. Did you check FB1? You can simply short FB1 if you find it broken. There will no impact to the scope without FB1.
Re: power up test no VBUS
Okay my mistake I installed the USB connector onto the wrong side of the board 
I have worked through installation guide and now:-
Powered by USB
JP1, JP2 and JP4 closed scope is working.
Compensation capacitors adjusted and looking good.
Basic test of all functions looking good although will fully test when case mounted.
Re-installed BOB3 switch, removed JP2 and scope will not power up. I will raise another post regarding this as different subject.
I have worked through installation guide and now:-
Powered by USB
JP1, JP2 and JP4 closed scope is working.
Compensation capacitors adjusted and looking good.
Basic test of all functions looking good although will fully test when case mounted.
Re-installed BOB3 switch, removed JP2 and scope will not power up. I will raise another post regarding this as different subject.