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worlickwerx / pi-parport

retro parallel port for raspberry pi
GNU General Public License v2.0
64 stars 11 forks source link

R1 missing from the v4 BOM #47

Closed iguanatamer closed 3 years ago

iguanatamer commented 3 years ago

What part is it on the board? I built the board but noticed it was missing.

quorten commented 3 years ago

This is labeled as a "DNP" (Do Not Place) part, the purpose is if you want to hard-wire write-protect rather than using the removable jumper. A 220 ohm resistor or less could work just fine, but this part is not necessary for the board.

On 12/29/20, afromanDAN notifications@github.com wrote:

What part is it on the board? I built the board but noticed it was missing.

-- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/worlickwerx/pi-parport/issues/47

quorten commented 3 years ago

Out of curiosity, how did you print the PCB? And which assembly technique did you use, reflow soldering or hand soldering + drag soldering for the LPT chip?

I have a more detailed assembly guide with photos from my second board assembly, but I haven't put it online yet. But point in hand, it's worth determining what info would be most helpful to relative novices in this area. And also I'm curious about the relative interest in this project, I'm guessing hand-assembling a small number of PCBs suits this project just fine but there could be the option of PCB assemblers for readymade boards in larger quantity.

iguanatamer commented 3 years ago

Well I tried reflow soldering on one of them but my solder paste applicator put too much on. Second one I did was with just hand soldering but i haven't tested it yet because I'm waiting on a terminator. I think the easiest way to make one of these is to use a solder paste template and a hot air gun.

andrewtubbiolo commented 3 years ago

Hey Dan:

 I got one of those $40 hot air units from China on Amazon. It did a

great job. I mounted mine on a surface mount to DIP 40 converter then hand soldered wires. I simple thin line across the pads and surface tension did the rest. I hand tacked the corners with some angle hair solder and a small chisel iron tip. I had two or three bridges I cleaned up with some solder braid.

I'm going to be doing a rev 4 after I order the board next week.

Andrew

On Tue, Dec 29, 2020 at 3:46 PM afromanDAN notifications@github.com wrote:

Well I tried reflow soldering on one of them but my solder paste applicator put too much on. Second one I did was with just hand soldering but i haven't tested it yet because I'm waiting on a terminator. I think the easiest way to make one of these is to use a solder paste template and a hot air gun.

— You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub https://github.com/worlickwerx/pi-parport/issues/47#issuecomment-752266829, or unsubscribe https://github.com/notifications/unsubscribe-auth/ABJINSSJONNFLFDF2MLFAI3SXJL4LANCNFSM4VM3RTJA .

quorten commented 3 years ago

Cool, my guide is largely photographed and written around a solder paste technique without templates. Granted my second board is not quite finished yet, but sounds like my recommendations are largely on track with what works well for other folks. I think I may post the detailed info I currently have in the next few days.

iguanatamer commented 3 years ago

Well I think I cooked the lpt chip. I would appreciate it if someone could make one for me.

quorten commented 3 years ago

@afromanDAN What makes you think that? Did you power it on and it didn't work? Multimeter tests to check for soldering problems on powered-off ICs can fool you because the 3.3v side has ESD protection diodes, so it should appear that all such pins are "bridged" together from an electrical test. But when you power on, it will "just work" so long as you've visually verified there are no bridges.

I'd be willing to mail you out my one finished and tested board if you're interested.

@garlick It might be worth creating a GitHub issue to discuss more about the possibility of stocking partially/fully assembled v4 boards. Also, thanks for sending me the two PCBs!

garlick commented 3 years ago

Thanks for helping out @quorten! I'll open an issue.

iguanatamer commented 3 years ago

@quorten That would be great if you could ship one out to me.

I'll close this issue now.

quorten commented 3 years ago

@afromanDAN Send me an E-mail with your address and we can follow up with additional details there. Same as my GitHub E-mail address. mako0042 at umn dot edu.

quorten commented 3 years ago

@garlick Digging deeper into this, there's a few things we should amend to our documentation and one minor bug in my driver install code that should be fixed. Good news is that one of the two boards @afromanDAN built actually fully works! I'll open another pull request soon.