My EPROM Programmers all have a connection foir external power specifically because sometimes USB can't provide the needed current.
bill On 02/05/2018 02:06 PM, Chuck Guzis via cctalk wrote: > On 02/05/2018 10:20 AM, Mark G Thomas via cctalk wrote: > >> 2) Many of the chips were failing to program because my Batronix >> programmer apparently requires more current than my USB port provides. >> This surprised me because I have been programming chips for years >> using this programmer on this computer port successfully, and this >> is the first I have had the problem. Using a Anker powered USB hub solved >> things. My Batronix programmer even arrived with a cheap powered hub >> when I ordered it, but I never used it because it was shipped with an >> incompatible wall wart, but looking at it in the box gave me the idea >> that this might be the issue. > You should be aware that many "thin" Far East USB cables will not pass > the full USB 1.5A current without substantial voltage drop. I recently > ran into this with a new LG portable DVD drive. It refused to operate, > even though I'd just taken it out of the box. I replaced the "thin" > USB cable with several other "thin" ones that I had with the same > result. Finally, in desperation, I located a "thick" USB cable, plugged > the drive in, and discovered that it worked just fine. > > Moral: There's a lot of garbage out there. > > Rant: The whole scheme of supplying anything but low-current using USB > is a terrible idea. I have a similar gripe with barrel connectors, > which don't seem to enforce any standard at all regarding polarity or AC > vs. DC. > > For my own projects I've taken to using mini XLR connectors. Perhaps not > optimal, but they're rugged enough. > > --Chuck > >
