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From: John Larkin on 20 Nov 2009 19:22 OK, I just got the first board from production this morning, for this spectroscopy controller thing. ftp://jjlarkin.lmi.net/First.JPG It gets 12 volts in, which runs an LTM8023 switcher brick to make 3.3 volts. The 3.3 runs most of the logic on the board (including a Spartan 6 and a PLX PCIe bridge, both BGAs) and also drives four secondary switchers and some LDOs to make 1.2, 1.5, 1.8, 2.5, and -5 for various uses. So when I powered it up everything went nuts. The PLX chip was obviously fried. After that was pulled, the Xilinx was running hot, and the 3.3 volt supply was bogged down to about 2.6. The LTM regulator was hot. Pulled the Spartan BGA next. Now the 3.3 volt rail wants to run at 5 or so. After much head scratching, I discovered this: ftp://jjlarkin.lmi.net/Swapped.jpg The resistor that's screened "R127" is actually R129. And vice versa. So the switcher was programmed wrong, told to run at an absurdly low frequency and an absurdly high voltage. The ref designators somehow got misplaced during layout. We usually check for this. Apparently our production people, when semi-auto placing dense parts, double-check the ref designator and plop the part into the "correct" place, even if the machine coordinates are a little off. I'll have to warn them to be suspicious about cases like this, especially on first articles. TGIF John
From: Martin Riddle on 20 Nov 2009 19:57 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:u0beg512h0fcels3arn2i6s9f8vcc6cqa9(a)4ax.com... > OK, I just got the first board from production this morning, for this > spectroscopy controller thing. > > ftp://jjlarkin.lmi.net/First.JPG > > It gets 12 volts in, which runs an LTM8023 switcher brick to make 3.3 > volts. The 3.3 runs most of the logic on the board (including a > Spartan 6 and a PLX PCIe bridge, both BGAs) and also drives four > secondary switchers and some LDOs to make 1.2, 1.5, 1.8, 2.5, and -5 > for various uses. > > So when I powered it up everything went nuts. The PLX chip was > obviously fried. After that was pulled, the Xilinx was running hot, > and the 3.3 volt supply was bogged down to about 2.6. The LTM > regulator was hot. > > Pulled the Spartan BGA next. > > Now the 3.3 volt rail wants to run at 5 or so. > > After much head scratching, I discovered this: > > ftp://jjlarkin.lmi.net/Swapped.jpg > > The resistor that's screened "R127" is actually R129. And vice versa. > So the switcher was programmed wrong, told to run at an absurdly low > frequency and an absurdly high voltage. The ref designators somehow > got misplaced during layout. We usually check for this. > > Apparently our production people, when semi-auto placing dense parts, > double-check the ref designator and plop the part into the "correct" > place, even if the machine coordinates are a little off. I'll have to > warn them to be suspicious about cases like this, especially on first > articles. > > TGIF > > John > > > Yea, know the feeling. Most people I've talked to agree that the first board always has some sort of problem(s). Cheers
From: don on 20 Nov 2009 20:00 John Larkin wrote: > ftp://jjlarkin.lmi.net/First.JPG > ftp://jjlarkin.lmi.net/Swapped.jpg > Hi John and all, This is a good example of what Jim was talking about. Inside Thunderbird, I click these links and up pops up I.E. I have checked Thunderbird for what it wants to call for ftp links. I do not find any config settings for this. Does anyone know how to re-configure Thunderbird to call Firefox instead. Thanks don
From: Joel Koltner on 20 Nov 2009 20:06 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:u0beg512h0fcels3arn2i6s9f8vcc6cqa9(a)4ax.com... > The resistor that's screened "R127" is actually R129. And vice versa. I (cough!) think most of us have had that happen... What's the big yellow silkscreened square around the oscillator-in-a-can for? Metal shield maybe? ---Joel
From: Joerg on 20 Nov 2009 20:26
don wrote: > John Larkin wrote: > >> ftp://jjlarkin.lmi.net/First.JPG >> ftp://jjlarkin.lmi.net/Swapped.jpg >> Hey John, you wasted lots of real estate there. Wish I could have some of that. Doing an EMC fix on a client design right now and I can't even shove one more 0402 part in there :-( > > Hi John and all, > > This is a good example of what Jim was talking about. > > Inside Thunderbird, I click these links and up pops up I.E. > > I have checked Thunderbird for what it wants to call for ftp links. > > I do not find any config settings for this. > > Does anyone know how to re-configure Thunderbird to call Firefox instead. > My Thunderbird does not do that, never did. Check Windows for preferences, IOW which program a certain file suffix launches. If no dice: Best may be to hose it all off your computer and do a clean slate install of Firefox and if that doesn't do the trick, Thunderbird as well. But save the bookmarks, email, addresses and whatever else you need. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |