Recreating a White Ceramic MOS 6502

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Joined: Sep 13 2016
Posts: 9

Greetings from San Francisco! I own a working Apple 1 replica originally purchased from a member here who lives in Italy. The board contained most correct features, chip makers and date codes that closely approximated a pre-NTI Apple 1 board. I purchased the board to achieve my hobby’s goal of displaying a replica that exactly duplicated the original. It was clear before my purchase that I would have to improve the accuracy of the board to create an exact copy. The more I reached out to members on this board, I realized that this goal would either take many, many years of sourcing chips and that some may be completely out of my price range. My wife is very understanding of my hobby but she does have her limits.

Continuing my investigation, I began to read discussions that focused on the ethical nature of duplicating an exact Apple 1 board. Folks were concerned that these boards would make their way to eBay for a 30K sale and fool the buyer into thinking they bought the real thing. This debate seems to have cooled since members have pointed out that turning a replica board over will reveal the PCB marker, in my case a Newton-1. Or other micro-differences that are not being publicized which reveals their true origin.

The only remaining confusion seems to be the question of why? Again, other members have shared that it is simply one part of our hobby that some folks enjoy the challenge and the process of recreating an exact replica. You either get it or you don’t. For me personally, it’s a hoot. So, I will soldier on.

Then I read other members posts who had decided to re-mark chips due to originals being completely unavailable. My two Proms needed this attention. In another post, I shared pictures of my Apple 1 Prom re-marking project to further accurize my Apple 1 replica. I personally did not sand the surfaces of the donner PROMS nor did I apply the stencils via the Toner Reactive Foil method. Rather, I replied on the help of members here to help me with skills that they perfected. The result was PROMS that looked exactly like the Apple 1 Prototype that appears the 1976 Apple 1 two-page flyer. I was delighted with the look that these PROMs gave my board and furthering my goal of exactly duplicating the look of a Apple 1 board.

My next goal is to remark a 40 pin chip that resembles a MOS 6502 CPU. The current resale prices are just below or above, $2,000 and completely unattainable for me. If a member here can make this available to me for under $500 I can Segway on to another project for my board. As I will not be holding my breath for that to happen, I have outlined my plan in this thread. The early MOS 6502 white ceramic CPUs were very plain with minimal gold shoulder areas at the top of the legs. Latter versions featured gold grounding straps along the center of the top surface.

Which brings me to the next topic, does it need to work? If it does, then a compatible 40 ping CPU need to be found. I would like to make a list of white ceramic 40 pin CPUs that would lend themselves to a remarking project. However, it the goal is to display your board in the most original configuration possible, but for those rare times that you are going to power up and demo Apple Basic or other short program, why not pull the remarked CPU and quickly insert your working 6502? My preference would be to have a working remarked ceramic CPU but that will depend on how difficult and expensive it is to find a compatible chip. In the the photo below is an example I purchase to experiment with. Obviously this 7552 is not intended to be functional.

Please give me your thoughts and observations.

Regards,
Theodore

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remarked proms.jpg83.76 KB
6502 examples.jpg187.22 KB

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Dog Cow's picture
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Joined: Dec 11 2008
Posts: 451
Re: Recreating a White Ceramic MOS 6502

Well my first thought is to just put a case over it so no one sees what kind of 6502 you have... Tongue

Seriously though maybe you could paint a plastic case white, age it, then see about getting a little brass plate with rounded corners. Someone could mill or stamp that, then age it as well. Glue it on top and print the MOS markings.

As for the pins, maybe these could be electroplated? But I don't know if you could electroplate the legs without ruining the 6502 circuitry. Maybe there's conductive paint that you could use instead.

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Joined: Oct 9 2011
Posts: 1016
Re: Recreating a White Ceramic MOS 6502

Actually I would not do what "Macky" suggests, if you keep pulling the 6502 in and out you will have socket problems, those TI sockets suck and I believe his board uses them.

Dog Chow, I like your idea, if your not going to spend 2k to get the right CPU, then simply take a plastic CPU, use ceramic paint, make a metal "name plate" and use a cheap "Wizard" disposable gold plating pen on the pins. I think the voltage is <5V so it should be fine plating the pins. I use the non-disposable version to touchup pins when I have to do a repair on a white 6502 leg.

From the side the painted plastic chip will never look the same as the real thing since it will be thicker, but from the top is should look good and more importantly it should work...

Cheers,
Corey

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Joined: Sep 13 2016
Posts: 9
Re: Recreating a White Ceramic MOS 6502

Excellent advice Corey, as always. I am abandoning any plans to frequently place and remove the cpu in my board's TI sockets. Your suggestion to paint a working donor chip with ceramic paint is a good one. I agree the effect would be very convincing.

However, why not use a MOS 6502 compatible cpu that already has a ceramic finish with gold DIP pins that match exactly such as the AMI or Intel 8080? Then one would only have to remove the logo and print the MOS information on top of the gold surface? I also agree with you that the bottom of the chip should have a mark indicating that is is a recreation.

Regards,
Theodore

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Joined: Oct 9 2011
Posts: 1016
Re: Recreating a White Ceramic MOS 6502

Are there any ceramic MOS 6502 compatible chips other than the synertek? A ceramic synertek is rarer than an MOS CPU.

evank's picture
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Joined: Jan 30 2005
Posts: 48
Re: Recreating a White Ceramic MOS 6502

I thought you would all enjoy seeing this picture of VCF's 6501. Smile

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Joined: Sep 13 2016
Posts: 9
Re: Recreating a White Ceramic MOS 6502

Thank you evank for the excellent reference photo! A thing of beauty it is. I am committed to recreating the look of the MOS 6502 and once I get my procedure dialed in, I will share my recreations with members here.