Building a NeoRam Ram expansion memory cartridge for the C64 computer

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banman
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Re: Building a NeoRam Ram expansion memory cartridge for the C64 computer

Post by banman »

Hi Zippy Zapp,



Regarding the beveling on the connector edge of the PCB boards. I honestly don't remember if I saw an option for it. I have just checked the order details and I don't see a mention of beveling. It asks if I request deburing and edge rounding, which I did not request.

The Gerber files that I uploaded seemed to contain all the details. The reason I say this is as soon as I uploaded the Gerber file the JLCPCB ordering system had configured all the board settings for me. That is, board size and thickness.
It is not like PCBWAY where one configures extensively the PCB design parameters after uploading the Gerber files.

Not too sure if this is a good or bad thing. I do know that it was a very fast process. You can get a look at what the PCB board will look like before comiting to manufacture.


I will post pictures of the PCB boards when they arrive and we can compare them to the PCBWAY boards I already have here with me.

Maybe eslapion can shed some light on the JLCPCB ordering system.


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Re: Building a NeoRam Ram expansion memory cartridge for the C64 computer

Post by eslapion »

Zippy Zapp wrote: Fri Oct 01, 2021 4:40 am Thanks guys. @banman, did you order with beveling? Just curious if the NeoRAM has the required space at the edge.
That's one strange question. The edge connector on C64 carts is usually made of 44 contact fingers with 1cm length. The beveling grinds less than 1mm long when done properly.
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Re: Building a NeoRam Ram expansion memory cartridge for the C64 computer

Post by banman »

Hi Zippy Zapp,

Maybe you are referring to this blank area at the start of the connector edge to the start of the beginning of the PCB metal connections.

Here's a picture of a PCB board from PCBWAY. I've circled the area that I think we are currently discussing.

Also one will note if viewed carefully that the beveling on the connector edge was only half done! :lol:

It looks like about a 1.5mm bare area.

The pictures are in hi res so click on the photos to see what I'm talking about.
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Re: Building a NeoRam Ram expansion memory cartridge for the C64 computer

Post by Zippy Zapp »

eslapion wrote: Fri Oct 01, 2021 3:19 pm That's one strange question. The edge connector on C64 carts is usually made of 44 contact fingers with 1cm length. The beveling grinds less than 1mm long when done properly.
Sorry, if that is a dumb question as this is out of the realm of my experience. The reason I asked is that when selecting the option to bevel it stated it couldn't be done unless there was enough space between the contacts and the board edge. My NeoRam PCBs from PCBway have no space unlike in the picture above.

@banman, Yes that is exactly what I am talking about. Mine do not have that gap. I used the gerbers in the NeoRAM distribution so not sure why it came out different. If I had selected that option they probably couldn't do it then I guess.
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Re: Building a NeoRam Ram expansion memory cartridge for the C64 computer

Post by banman »

Hi Zippy Zapp,

That's very interesting. I too used the PCBWAY web site to get the NeoRam boards made. They had the Gerber files on their website. That's what I used.
As you can see from the above pictures I was delivered boards with the gap and the dodgy beveling. I had several like this.
I wonder if others have had issues with PCBWAY boards?

I will be keen to see JLCPCB's boards when they arrive.

Zippy Zapp, use the picture with the ruler above and see if your board is about the same dimensions in length. Let me know. Maybe they make slight errors in production (look at the beveling on my PCB board!).
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Re: Building a NeoRam Ram expansion memory cartridge for the C64 computer

Post by eslapion »

Zippy Zapp wrote: Sat Oct 02, 2021 8:15 am
eslapion wrote: Fri Oct 01, 2021 3:19 pm That's one strange question. The edge connector on C64 carts is usually made of 44 contact fingers with 1cm length. The beveling grinds less than 1mm long when done properly.
Sorry, if that is a dumb question as this is out of the realm of my experience. The reason I asked is that when selecting the option to bevel it stated it couldn't be done unless there was enough space between the contacts and the board edge. My NeoRam PCBs from PCBway have no space unlike in the picture above.

@banman, Yes that is exactly what I am talking about. Mine do not have that gap. I used the gerbers in the NeoRAM distribution so not sure why it came out different. If I had selected that option they probably couldn't do it then I guess.
It's not a dumb question at all. Quite the contrary.

In fact this is forcing me to think about the way I make edge connectors on the Behr-Bonz and upcoming C64 cartridges.

In the past I never truly worried that the beveling might grind into the fingers of the edge connector by a few mils as they are gold plated on just about everything I do. Now that I think of it this has the effect of slightly exposing the copper under the gold layer and could cause a start of oxidation.

AFAIK, if you get your PCB made at JLCPCB and ask for ENIG then choose gold plated connector with chamfering they should make you the very best connector and they will adjust the necessary spacing for you.
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Re: Building a NeoRam Ram expansion memory cartridge for the C64 computer

Post by banman »

Hi eslapion and Zippy Zapp,


eslapion wrote: Sun Oct 03, 2021 12:40 am In the past I never truly worried that the beveling might grind into the fingers of the edge connector by a few mils as they are gold plated on just about everything I do. Now that I think of it this has the effect of slightly exposing the copper under the gold layer and could cause a start of oxidation.
WOW! That's amazing deductive reasoning eslapion. :o

That's exactly what I can observe on at least one of the PCBWAY boards. Only I'm using HASL. Actually it makes it more observable contrast between the copper and solder colours.
Look at the images I've circled. It is more prominent to the naked eye.
Please note I've only used this PCB board from PCBWAY less than 8 times. It does in fact have a 45 degree beveled edge that runs the entire connector.

On the first picture there is very slight gap between the end of the beveling and the start of the metal contact. In the last picture with the circles there is no gap between the beveling and the metal contact. The metal contact with the extra solder was me trying to get rid of the exposed copper.
A very sloppy attempt by me!

Click the pictures for a clearer look... :D
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Re: Building a NeoRam Ram expansion memory cartridge for the C64 computer

Post by Zippy Zapp »

eslapion wrote: Sun Oct 03, 2021 12:40 am AFAIK, if you get your PCB made at JLCPCB and ask for ENIG then choose gold plated connector with chamfering they should make you the very best connector and they will adjust the necessary spacing for you.
Well that is cool. Thanks for the info that helps a lot. I will place an order and see how it goes. If it looks good I will replace a bunch of boards I havent used yet that fit rather tight on a couple of my 64s. That should help that a lot.

Thanks!
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Re: Building a NeoRam Ram expansion memory cartridge for the C64 computer

Post by eslapion »

Zippy Zapp wrote: Mon Oct 04, 2021 5:22 pm
eslapion wrote: Sun Oct 03, 2021 12:40 am AFAIK, if you get your PCB made at JLCPCB and ask for ENIG then choose gold plated connector with chamfering they should make you the very best connector and they will adjust the necessary spacing for you.
Well that is cool. Thanks for the info that helps a lot. I will place an order and see how it goes. If it looks good I will replace a bunch of boards I havent used yet that fit rather tight on a couple of my 64s. That should help that a lot.

Thanks!
Please note I discovered something rather annoying about JLCPCB. When I did choose gold plated connectors and chamfering, I could no longer use the assembly service. I could only get bare ENIG PCBs.

That was a rather unpleasant surprise.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders
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Re: Building a NeoRam Ram expansion memory cartridge for the C64 computer

Post by Zippy Zapp »

Thanks for the heads up. I am usually only ordering bare boards so that is not going to affect me. But, yeah, if you use that service that is kind of annoying.
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