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From: JosephKK on 28 Nov 2009 07:40 On Mon, 23 Nov 2009 15:21:24 -0800, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Fri, 20 Nov 2009 16:22:15 -0800, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>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 >> >> > >OK, we fixed the power supply and replaced both BGA chips. > >ftp://jjlarkin.lmi.net/First_Light.jpg > >On the aluminum plate is the Kontron SBC, running Linux. It connects >to our controller board through the short silver PCI Express jumper >cable. > >So far, it's powered up, things look reasonable, and we have Linux >talking to the PCIe chip. Next step is to get the FPGA configured and >doing stuff. > >The NewHaven LCD looks real nice. The Kontron is talking to it RS-232, >with a little AVR processor on the user interface board handling the >LCD and buttons and LEDs. > >John > Interesting power distribution used there.
From: John Larkin on 28 Nov 2009 21:46 On Sat, 28 Nov 2009 04:40:38 -0800, "JosephKK"<quiettechblue(a)yahoo.com> wrote: >On Mon, 23 Nov 2009 15:21:24 -0800, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Fri, 20 Nov 2009 16:22:15 -0800, John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>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 >>> >>> >> >>OK, we fixed the power supply and replaced both BGA chips. >> >>ftp://jjlarkin.lmi.net/First_Light.jpg >> >>On the aluminum plate is the Kontron SBC, running Linux. It connects >>to our controller board through the short silver PCI Express jumper >>cable. >> >>So far, it's powered up, things look reasonable, and we have Linux >>talking to the PCIe chip. Next step is to get the FPGA configured and >>doing stuff. >> >>The NewHaven LCD looks real nice. The Kontron is talking to it RS-232, >>with a little AVR processor on the user interface board handling the >>LCD and buttons and LEDs. >> >>John >> >Interesting power distribution used there. We're using an external 12 volt supply and one of these http://www.mini-box.com/s.nl/sc.8/category.13/.f which plugs into the mini-ITX processor board. Switched +12 and +5 come out of it and power our spectrosopy board (which has 5 more switchers and 3 linear regs of its own) and has power distribution for the hard drives. Seems to work. This instrument is basically a PC, but we don't want it to look like a PC. Most PCs are wiring hairballs inside. That AC powered fan is temporary. We'll use a temperature-controlled DC fan in the real rackmount box. The Kontron has a connector for that. John
From: JosephKK on 29 Nov 2009 23:18
On Sat, 28 Nov 2009 18:46:30 -0800, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Sat, 28 Nov 2009 04:40:38 -0800, >"JosephKK"<quiettechblue(a)yahoo.com> wrote: > >>On Mon, 23 Nov 2009 15:21:24 -0800, John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Fri, 20 Nov 2009 16:22:15 -0800, John Larkin >>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>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 >>>> >>>> >>> >>>OK, we fixed the power supply and replaced both BGA chips. >>> >>>ftp://jjlarkin.lmi.net/First_Light.jpg >>> >>>On the aluminum plate is the Kontron SBC, running Linux. It connects >>>to our controller board through the short silver PCI Express jumper >>>cable. >>> >>>So far, it's powered up, things look reasonable, and we have Linux >>>talking to the PCIe chip. Next step is to get the FPGA configured and >>>doing stuff. >>> >>>The NewHaven LCD looks real nice. The Kontron is talking to it RS-232, >>>with a little AVR processor on the user interface board handling the >>>LCD and buttons and LEDs. >>> >>>John >>> >>Interesting power distribution used there. > > >We're using an external 12 volt supply and one of these > >http://www.mini-box.com/s.nl/sc.8/category.13/.f > >which plugs into the mini-ITX processor board. Switched +12 and +5 >come out of it and power our spectrosopy board (which has 5 more >switchers and 3 linear regs of its own) and has power distribution for >the hard drives. Seems to work. > >This instrument is basically a PC, but we don't want it to look like a >PC. Most PCs are wiring hairballs inside. > >That AC powered fan is temporary. We'll use a temperature-controlled >DC fan in the real rackmount box. The Kontron has a connector for >that. > >John Kinda cute. Nice to know such exists. |