I have tried all PP1 to PP4 settings. The Help / About gives:
Release 5.13.9 - 32 bit
ADC200 Driver V4.02
Error 12 (H13 S61)
Thanks for the reply. The database deletion comment was tounge in cheek, I know what PHPBB2 is like sometimes
Anyway, I have tried all the PP* settings but 2 to 4 give me an immediate not connected while PP1 does think about it for a second - more often than not. I have tried the power management on the USB, I always disable that in XP as a matter of course anyway.
I have made slight progress tonight but after 5 hours no solution though. I don't know if it's because this ADC212/100 is old (by old I mean might draw slightly more current / might be bit more susceptable to PSU regulation?) the number on the bar code sticker is *BJL57/021* and when working the batch number is BJL57 and calibration date is 17 December 2001 if that gives you a clue but, with the original mains adapter I get the parallel port working and USB not. I do use the ADC for automotive stuff now and again and I have tried it with my own 12v connector to the ADC which only consists of a 1N4001 as a series polarity protector. This I powered from my mains bench variable power supply.
The desktop machines that didnt work before do now using this alternate power supply. I have scoped (mains powered Hameg scope) the original adapter that came with the ADC and it is sat at 15.5v with 1v peak to peak ripple which drops slightly when the ADC is running. I don't think its that though as such. My desktops here are powered by a UPS and the workbench 240v supply is through a mains isolating transformer. I thought it might be due to a combination of the UPS and isolating transformer so I have tried powering the desktops straight from the mains and using the original ADC mains adapter from the same socket and it still fails. Every combination fails apart from the desktop being powered from any mains source (either incoming mains, UPS or mains from isolating transformer) and the ADC being powered from my bench power supply which is supplied from unisolated incoming mains - not tried supplying the bench power supply from anything else as there isn't any point as the USB converter even fails with the ADC being powered by a decent 12v sealed lead acid battery, why this is really doesn't compute because a large battery like this is surely more regulated than my bench supply even with its 10,000uf smoothing cap.
The laptop is the same - ish. The USB converter only works on the laptop with the charger plugged in and the ADC powered from the bench variable power supply or the 12v sealed lead acid battery AND I have a wire from a probe earth on the ADC to the negative on the charger input to the laptop AND ONLY the charger input, connecting the earth of the ADC to any other earth on the laptop doesnt work - it still fails. There is however a 0.12mA current measured between the other earths on the laptop and the charger earth. I have obviously checked and the charger input is physically connected to the other metal earths on the various connectors the laptop has. The laptop, on the odd occasion, still fails though with this configuration.
At first I thought this has to be data corruption surely, slightly different earth potentials upsetting things but when the laptop is battery powered and the ADC is powered from a battery what can the problem be, there is no charging going on and therefore no voltage drop anywhere. I have also tried the USB converter with no parallel lead - ie. USB converter connected directly to the ADC and also another USB lead between computer and converter. Also, when it does work, on every program start (before resetting offset null), it does look like a negative 2mV bias on Channel A (not looked at B) but the significance of that I don't know, this is on either USB converter or parallel input to any computer tried.
All earths on every bit of equipment / cables / etc. do check for continuity so any more ideas are very much welcome.