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A/V SBC with Multiple 65xxx CPUs http://forum.6502.org/viewtopic.php?f=10&t=5867 |
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Author: | ElEctric_EyE [ Mon Dec 30, 2019 9:49 pm ] | ||
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs | ||
Starting the soldering today using my hot plate that I've used years ago. It still works very well. There's an old thread in here in the Programmable Logic section about SMT reflow where I showed it off. It has the link to where I based the design. It has 1 thermocouple and 4 heating elements in a 1" thick 8"x6" block of aluminum. It takes about 30 minutes to get it to 200C from room temp. After that, the board goes on for about 5-10 seconds. To cool it down quickly I place it on an identical block of aluminum at room temp which quickly draws the heat away.
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Author: | ElEctric_EyE [ Mon Dec 30, 2019 9:55 pm ] | |||
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs | |||
I'm starting with the JTAG section as I've never used SPI FLASH to program the Xilinx Spartan 6. I've always used the Xilinx PROMs with no problem. So after soldering, I'm check out the connections using a USB microscope. And after looking at this pic, I've realized I forgot to add flux! Bad solder joints. Hopefully adding some flux after the fact and reflowing will refix the problem.
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Author: | ElEctric_EyE [ Mon Dec 30, 2019 10:45 pm ] | |||
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs | |||
Attachment: After flux. Did not solve the problem.Here I've added the SMALLEST amount of Chipquick liquid solder. Some interesting pics.
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Author: | ElEctric_EyE [ Mon Dec 30, 2019 10:52 pm ] | ||
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs | ||
Final desired result, close enough anyway. 4th reflow. Not good. However, I am developing a SOP for IC's at least. Individual 0402 packages will be the real challenge, but I had no choice! Now it's off the ultrasonic cleaner with a heated solution of Windex. Caveman make SMD boards
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Author: | kakemoms [ Tue Dec 31, 2019 7:51 am ] |
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs |
You may want to consider a two-step reflow process to get better solder joints. Going all the way to solder temperature at one step within a few seconds will give you all sorts of problems. One of them is "splatter" of the solder which will remove the solder from one point and deposit it all around. I believe that is what you are experiencing. One way to do this is to increase the temperature of the board more slowly. You can put your hotplate at a lower temperature and use some thermal resistance between the hotplate and your board. For example another PCB. That will bring your board up in temperature more slowly. You will then need to finish the reflow with a heatgun (or alike) to bring the components up to the final solder temperature. Keep the components at reflow for around 30 seconds and then bring the whole board down in temperature again. With a heatgun, the board will go down to the hotplate temperature, and then you can take it off (the hotplate) and let it cool. Try to prevent temperature shocks. You may want to look at this link (look under "reflow profile") to get a better understanding of what can happen if you shock your boards. |
Author: | ElEctric_EyE [ Tue Dec 31, 2019 2:20 pm ] |
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs |
I think you're correct, a hot air gun would probably help. Also, after watching some more videos I realized I need liquid solder. I'm using solder paste currently and it's preventing me from applying as much as I really need. |
Author: | ElEctric_EyE [ Tue Dec 31, 2019 8:15 pm ] | ||
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs | ||
So for the FLASH PROM's I just applied more flux and hit each pin with the soldering iron. I think that's what I'm going to wind up doing for everything. I tackled some 0402 passives using the hot plate and heat gun. The flux kept the parts from being blown away. Then I let it cool down, reapplied some flux and hit each end with the soldering iron with the slightest bit of solder on the end. I'm almost done with the JTAG section. 4 0402 resistors have been soldered in, the DS1818's with internal 5.5K pull-up resistors are soldered in. I believe all that's left are the reset buttons, the FPGA's and the JTAG connector. Ah, and the voltage regulators which I still have to order. Here's the schematic for the JTAG section. I realized I made an error on the silkscreen labeling the Master and Slave reset buttons. They're switched. I'll have some more pics after I solder in the FPGA's.
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Author: | ElEctric_EyE [ Tue Dec 31, 2019 9:50 pm ] | ||||||
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs | ||||||
144-pin .5mm QFP's are a breeze to solder in. There's enough solder already on the new board, so I've done exactly what I've done so many times in the past for these QFP's: Just applied flux, laid the IC on top and swiped a fine tip soldering iron, @450deg F, towards each pin. Nice, clean and neat. No hot plates, no heat guns, no liquid solder. I'll be doing the same for the 100-pin .5mm QFP SyncRams, if I get that far with this version of the board. The 0402 passives are the only challenge here I think. Here's some pics after a hot ultrasonic bath in 91% Isopropyl Alcohol.
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Author: | ElEctric_EyE [ Tue Dec 31, 2019 10:30 pm ] | |||
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs | |||
Soldered in 2 of the 3 voltage regulators and also the main power in receptacle. The VGA connector was just snapped in for show. The point of this first stage is to verify JTAG programming. Putting in an order for some stuff. See you next year!~
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Author: | ElEctric_EyE [ Wed Jan 01, 2020 12:52 am ] | ||
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs | ||
Temp storage... Need a few parts.
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Author: | ElEctric_EyE [ Mon Jan 06, 2020 9:37 pm ] |
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs |
I got the TPS756333 5A 3.3V linear voltage regulator, soldered it in, powered the board up and measured the 5V in, 1.2V, 2.5V and 3.3V. All are within spec. So tonight I'll finish off by scavenging the JTAG connectors from an old PVB board and I should be able to test the programming of the FPGA's using ISE14.7. This is two steps forward. I did have a 1 step backwards moment when my main desktop computer failed to boot on Jan 2nd. Jan 1st I was away. Very very curious timing for this failure! However, I was prepared as I backed up everything to bluray when I had the boards made weeks prior and can proceed with JTAG testing on another computer very soon! Xilinx has updated ISE 14.7 for Win10 but it's only good for the Spartan 6 which is fine in my case. |
Author: | BigEd [ Mon Jan 06, 2020 10:13 pm ] |
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs |
Good save with the backups! |
Author: | ElEctric_EyE [ Tue Jan 07, 2020 8:58 pm ] |
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs |
BigEd wrote: Good save with the backups! I've learned. But still learning. My backup RAID5 server is on that computer that is down. It has operating system images, ISE images and project files... Next plan is to make that RAID5 array mobile. So I must download many GB worth of data for ISE. 2nd attempt today after 7GB yesterday when I tried installing Xilinx' newest Windows 10 version but it runs under a virtual machine which will no doubt slow down the entire ISE environment. I can't tolerate that. So I'm downloading the previous version for Win7 and trying this fix again. This will take another 3hours to just download. |
Author: | ElEctric_EyE [ Thu Jan 09, 2020 12:01 am ] | |||
Post subject: | Re: A/V SBC with Multiple 65xxx CPUs | |||
Still working out the ISE 14.7 install... iMPACT is not being installed for some reason, so I can't test the JTAG yet. Seriously pissing me off,,, I have to bring my old machine back up and reanalyze this whole PC failure situation. Today I've installed the JTAG connector and took 2 pics with the 5V 11A power connector. That power is coming from an old ATX switching power supply. Plenty of current and good regulation. Be patient with this old geezer!
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