alexconway

One year later and I can now buy geniune FT232H, rather than take a chance with one desoldered from an Ebay hobby board. And a replacement genuine FT232H fixes it, as far as I can tell at the moment... Cheers Alex

I have probed the Eeprom and at power up there is activity on Chip select, but clk and data both remain high - not due to being shorted to 3V3 but because of the 10k pull-ups. This is on the pins of the FT232HQ and the Eeprom. It's tantilisingly close... As to how I broke it: I was using the analog inputs set to 100mV/div, differentially measuring two dc voltage outputs that were 0.25V - 1V. The AD2 GND was also connected to the GND of the test circuit. The circuit generating these outputs was powered from 18V bench supply - with a fair amount of transient current ability and a floating output, so GND was connecting thru the AD2. I accidentally shorted something to something - I think I left it powered and put my grounded soldering iron on the 18V. Effectively I forced the 18V of the bench supply to be GND and the GND to try and be -18V. The result was as above. I'm guessing that at 100mV/div there is still attenuation in the analog input circuit, so I don't think the current flowed there, so it must have been between the AD2 input GND and the soldering iron GND, thru the powered and grounded USB hub. Cheers Alex

I have now replaced the FT232H, and it appears as a RS232 COM port on device manager, VID 0403, PID 6014 I started up Waveforms and tried to use the Device Fix, but it fails with the message "FT_EE_Program failed (12)" Is there any info about what error 12 is? I have checked that the EEPROM (the 6 pin SOT23 in my photo) has 3V3 power going to it: all pins are at 3V3 except the gnd pin and clk (which I have checked is not shorted to GND) Any pointers?... Thanks Alex

Hi @attila I shorted it and now windows doesn't even register an error for it. There is definitely 5V getting to it. When I unplug it and measure resistance from Vbus to GND I get a reading of 64Ohms. And pin 2 of the USB Micro B connector measures 1Ohm to GND, but pin 2 is open. Are there any other protection devices that might be shorted? Otherwise it looks like the USB receiver is busted. And, to add to my misery, the port on the USB hub I was using no longer works. Thanks Alex

Hi there, I have an AD2 which just stopped working. Windows complains "device descriptor request failed". I looked around the board and have found a cracked compoment under the USB connector. It looks like a ferrite bead. Does anyone know what I could replace it with? Thanks, Alex