After six days of waiting, I finally got my new PCB. Six days isn't a long time for a new PCB from China but when you're a kid at heart, everything takes forever. lol

My initial impression is the quality looks very good (to my untrained eye, anyway).

For those wondering, the name "Potpourri6502" comes from the computer it's mostly designed from. The 6502 on the primer site under Circuit Potpourri.

http://wilsonminesco.com/6502primer/potpourri.html

There are certainly some differences, but that design is easy to understand.

Anyway, this is only my second PCB. My first PCB was a disaster that had way too many errors to salvage. On this design, I learned so much more. In fact, I learned new tricks halfway through the layout. If I were to do it again, I know I could make it much better. Oh well...live and learn.

So far, it tests out electrically. No shorts or missing connections that I can find. I have one board that has the sockets, voltage regulator, LED, etc. soldered up and it works fine. Later this evening, I hope to slowly start testing a free-running 65C02. I have a good frequency generator so I can slowly ramp up the speed.

Now the bad. I made some obvious mistakes. The biggest mistake I made (so far) is the 7805 voltage regulator. I don't know how I missed that. But I totally chose the wrong package size. I should have printed the design out before sending off and done a dry-fit. I will do that next time. I seriously thought I had the right one picked. I even remember someone mentioning it looked wrong and I assured him it was correct. Again, a stupid blunder on my part. The good news is that I can still make it work with three small bodge wires. I just mount the 7805 in the mounting hole and run the wires to the pads. Works great and the ugly factor is about a 4 out of 10. I figure if this is my biggest mistake, I'm happy.

Second mistake are the resistors. Again, wrong package size. So they have to be stood up vertically. Not the end of the world, but looks embarrassing considering there is plenty of room for them to stretch out. Fortunately, there aren't many resistors to speak of.

Third mistake is the ZIF ROM socket. This was a real blunder. I thought I left enough room for it to fit but it's not even close. I forgot just how big those things are. The bar cannot come down without cutting it. And the tail end of the socket overlaps C1. So, I'm just going to use a dual-wipe socket instead. Annoying, but not a show stopper. If I *REALLY* wanted it to work, I could put C1 on the bottom and cut the bar of the socket. A hack but it would fit then.

Finally, the routing, as Dave would say, is a little "how you doing?" in parts. I admit, towards the end I started getting tired and just wanted it done. My first design I used the auto-router and it was a disaster. This design, I did every trace by hand. So next design will be cleaner.

So those are the major hardware flaws I've found so far. I will probably find others as I start populating the board. But considering this is only my second PCB ever, I'm still excited that I got this far. The next one will be even better.

The other mistakes are purely cosmetic. On U9 (65C22), I got the labels backwards for CA1 and CA2. They are electrically correct out to the header. In other words, the header (the more important part) is correct.

Next, I should have labeled the pins on the two glue chips. I labeled everything else. But considering almost no computer in the 70's/80's labeled every pin, and I almost did, I think I am ahead. I like the labels. I wished most computers did that.

I also should have labeled the functions of the VIA and MPU instead of just the model numbers. I labeled "RAM" and "ROM" but not "VIA" or "MPU".

Finally, the customer information JLCPCB prints on the board should be on the back. JLCPCB has a feature where if you put a label called "JLCJLCJLC" (or something similar to that), then they will replace it with the customer information. I did that but they didn't do their part. They literally printed the label "JLCJLCJCL" on the back where I wanted but then printed the customer info on the front. I'm going to contact them about that because, as far as I can tell, I did it exactly like they said. My thinking is that they may not support that on the back of the board. But their docs didn't say so.

Sorry for the long rambling. I will post more details as I move along.

Wish me luck!


**EDIT**

Not sure why the forum software is showing the image rotated when zooming in.

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Cat; the other white meat.

Very nice cbmeeks. The board looks great, and I too really like those pin labels — so helpful for debugging and patching. I can attest to soldering to the wrong pin more than once!

Also, I wouldn’t sweat the glitches. If you can work around them there’s literally no harm done.

Cheers!

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C74-6502 Website: https://c74project.com

PCB layouts generated by autorouters always tend to look bad.

Manually routing a PCB could turn out to be labor intensive at some point,
but as a reward, debugging/repairing a manually routed PCB tends to be more simple.

We all have learned by try and error... and even if you did PCB layouts for 20 years as a living:
the first revision of a PCB always tends to end up in the trash can.

Good luck with getting the SBC up and running !

If that is your second PCB ever, then congrats on a fine job!
I still have my first board ever made, which was made 100% upside-down.
Looked just fine on screen, but I had top and bottom layer reversed.

Brad

Thanks for the kind words.

Yeah, I still have my first board too. It's not like I can use it for anything else...maybe a coaster. lol

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Cat; the other white meat.

Funnily enough I do have some coasters made of old boards... not my boards. I can't help trying to figure out what they are, but of course they could be anything.

If you used 1/8 watt resistors, would those fit?

Probably you could solve this by using the third dimension -- I mean elevating the ZIF socket vertically off the board. In this post I talk about doing that with PLCC sockets (although for a different reason).

-- Jeff

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In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html

Hmm. Perhaps. Right now I'm just using what I have in inventory. When I get the board up and running, I will post some more pics of all of the brutal hacks I had to do. lol




Oh yeah...I certainly entertained the idea of moving up like a skyscraper. I might end up doing that. If I did this board again, I would go one step further and find a way to program in-circuit. I *ALMOST* did this initially but I was running out of time and just wanted the board done. However, I bet I could still do it. I could pull the ROM out and put it in an expansion card in one of the four slots. Then run some wires to my programmer. Or, perhaps run a ribbon cable from the ROM socket over to a programmer. Then replace the ribbon cable when completely done with programming.

That's half the fun...figuring out ways around (my own) design limitations.

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Cat; the other white meat.