On 2 March 2018 at 09:22, Andre <an...@lanoe.net> wrote: > Maybe one bad resistor? I've read that tin whiskering can occur even on > relatively recent equipment, slower than lead free but still a problem. > I'd do a visual inspection just to see, shouldn't be an issue. > -A >
An issue with fingerprints would not totally surprise me. It is obvious the seller had multiple meters, which were sent to a lab, which I am suspicious of*. The seller said the lab would have swapped pieces between units to try to get one working. He had at least 3. 1) My one, which has a recent(ish) Agilent serial number, and Agilent written on the back, but an HP front panel. 2) Another which has HP on the back, but an Agilent front panel. 3) Another said to be working. * I consider is lab suspicious, the fact mine was sold as having no output, yet there was output, and it was within spec. It could be an intermittent fault of course. So its almost certain bits have been swapped between different units. It is is finger prints, what would be the best way to remove them? I see some say IPA, but others have said that can disolve solder resist. I once had a Sun workstation which had one of the covers missing of the back where sbus expansion cards https://en.wikipedia.org/wiki/SBus were supposed to be put. This was stored in the garage. Some mice decided this Sun would make a nice home, and used it as a toilet! Needles to say the board was covered in what mice excrete. After various attempts to get it back to life, an hour or so in the bath with plain tap water did work. But of course very low currents of the 4339B would prevent different challenges to a digital board, where signals are either 0 or 1. But whilst the 4339B may not be free of finger prints, it has not been used as a mouse loo. So if it does require cleaning, it should be fairly modest, but I have no idea what to use. I buy a IPA on eBay for cleaning, which is claimed to be 99.9% pure, but I doubt it is really that pure, so if IPA was used, I would buy from a proper chemical supplier. Dave _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
