Mastodawn

The real thing showed up today, seems good.

The rails under the IC are the power lines, positive is the upper rail, ground the lower. Should allow easy connection to vcc/gnd for most dip packages.

Common ground all over the board, but each of the 6 sections has an isolated VCC. You can bridge them with solder, if needed. This was done to allow mixed 5v/3v3 on the same board (as we need to do more these days).

Each solder spot has an adjecent, connected spot to allow access to that pin, either via wire or header pin.

Finally, there's another two rows of columnar joined pins that go across each section, so it could be nice for buses.

I guess the proof will be in the assembly.

Oli W 🌱Apr 29, 2023

Rookie error. The holes are OK for sockets, but too tight for the normal square header pins (except the lower two rows).

Oli W 🌱Apr 29, 2023

It's nice having gnd and VCC right next to the places you need them most though.

Giles Goat Apr 27, 2023

@evolutional It looks REALLY GOOD .. but .. there is "the problem" .. "where are the DIL 74XX chips ?" .. My "progression" ( into DESPAIR ) went from DIL -> SMD -> 74xx can't find them so many any more -> CPLDs -> Xilinx -> Altera -> PLCC44 -> 5V -> 3.3V -> VQFP/TQPF 44 -> Microscope -> Adapters -> TOO TINY ! AAAAAARGH ! I survive with some "stock" I bought long ago ( and very hard to find now ) Still have to try alluminium stencils + adapters + heat gun .. the problem components are ( CONT )

Giles Goat Apr 27, 2023

@evolutional getting smaller and smaller and harder and harder to solder, also when doing "small computers" the number of chips is quite a thing cause bus transceviers/drivers to increase the fan-out I mean you can put rom/ram/cpu etc in a board but then you need a bus that can drive something, could not find yet "a decent SerDes" for "home use" and attempt a fast serial bus.

@gilesgoat the pain is real :(

RC2014 Apr 22, 2023

@evolutional People often question why the standard RC2014 modules are (barely) 39 pins.

At the time, 100mm limits were a lot more common with PCB manufacturers than they are today. Also, a lot of people used Eagle back then, which was free for hobby use up to 100x100mm.

Oli W 🌱Apr 22, 2023

@rc2014 the cost from 100mm to 100.1mm is $5 for 10 to $30 for 10, so adds up...

Oli W 🌱Apr 22, 2023

@rc2014 I also imagine the DRC warnings you get on every job, those through holes are slightly clipped 😂

RC2014 Apr 22, 2023

@evolutional
DRC are only suggestions. Right? 😬

Oli W 🌱Apr 22, 2023

@rc2014 meh if it gets another pin in there, why not.

@evolutional

*SOB* .. WHY ? WHY 100x100mm ??

WHY NOT 160x100mm ??!!

</Despair>

( I meant all time I see $5 offers for formats like those and the moment one wants 160x100 the prices skyrocket )

.. if you ask "why 160x100" then "you don't know" ..

@gilesgoat hah, because that's the cheap tier at Pcbway and I'm being a skinflint

@gilesgoat yeah the price jump from 100x100 to even something a tiny bit higher is sorta nuts.

If this works out as a format I'm very likely to bump up the size though, as I'm almost certainly going to need it

@evolutional I used to do PCB at home with all the problems that come out. My problem with stuff like PCBway is that "cheap" well "yes if you plan to sell what you do" ( and recoup some of the costs ). MY problem is that for doing "one or two pieces for myself" that BTW could be "a test" may need further modifications is still "a bit too expensive". Plus I like to work rackmount/Eurocard format so you see the problem.

@gilesgoat yes! Very much this.

I'm down in the rabbit hole of home fabrication too. The current (and probably final) experiments are with photo resist methods. I bought one of those cheap cnc machines thinking it'd help, but I've had nothing but a terrible experience doing anything bigger than tiny boards on it.

@gilesgoat I don't need half a dozen professional grade boards that done work, I want a single board I can make a few mods to when things just don't work. Plus I don't want to wait 3 weeks for them to rock up only to find there's bugs.

Thats the motivation for trying out some of these custom proto boards. They should be good enough to solder a few things together and maybe even wire wrap some of the buses.

@evolutional
Can't do it right now, I am supposed to work 😂 But maybe later I can exchange with you some of my HOME PCB fabrication experiences/suggestions. "I went into that rabbit hole form many years" I can do dual layers PCBs. Single side "no problem" .. but nowadays the problems are the CHIPS, 0.5mm pitch and stuff like that. CNC I am NOT sure is the way to go I am afraid. As I said "let's talk later" :) I can send you some pictures and things and tell you "experiences".

@gilesgoat aye very much interested in this. I get really shit results most of the time 😁

@evolutional I may try to make some document ( maybe with pics ) titled "experiences in home PCB design" .. as what I have to say on the subject is a bit long for "a few posts".

@evolutional It's really like "chemistry" once you found "a recipe/method that works" don't change it, and note it down precisely what you done. 60% of the problems is in the quality of the photo-resist applied to the PCB. 40% in the print quality of the 'master'. I used to buy pre-sensitized PCBs from RS and I think was MEGA UK, doing it with spray/etc. is really difficult, I haven't tried yet with FILM now that it seems affordable.

@gilesgoat the main thing I've noticed with the film approach so far is that it seems to be really easy to get an uneven application. Eg, a tiny bubble or wrinkle can leave gaps.

Interesting thought on the initial master print quality too. My 25 year old laser printer is probably going to be pretty rough

@evolutional .. don't tell me you too have an HP Laserjet P1505 ... and yes I tried even those "special translucents for PCBs" they are a BIT better than tracing paper but NOT that much ( or the printer isn't ) ..

@gilesgoat it's some Brother laser printer I bought in 2002 and it still has the original laser toner cartridge. I don't think it'll ever run out haha

Thilo, EE 🤘🏼⚛️ 🇪🇺🎗️🇺🇦🇵🇸Apr 24, 2023

@gilesgoat @evolutional That would've been a logical choice from a technical point of view.
Commercially, it makes a lot of sense to put that format in a higher tier. 😁

gazsp Apr 28, 2023

@evolutional Wow, this looks really good. Any chance of open sourcing the KiKad files? Yes, I’m cheeky. Feel free to tell me to bog off of course :).