My version of the Apple 1 "replica"

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My version of the Apple 1 "replica"
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Hello,

 

This is my first forum post. I wanted to say hi and introduce myself. My name is Mateusz and I am from Poland.

Recently I have wanted to build my own versions of "replicas" Apple 1.

PCB board made of publicly available gerberas. Most TTL ICs from my own old stock. Instead of DS0025, I used DS0026 from my local store. Capacitors C5 and C6 according to the scheme - 1uF.

I built two versions. One on the AM1404APC in DIP, the other on MM1404AH in TO99. Both versions work fine. RAM chips are MK4027. In one version there is a MOS 6502A processor, in the other one, a counterfeit MOS 6502 bought in China (which also works!). Oneshot from 74123 is 480ns. (47pF mica and 19KOhm).

Unfortunately, I do not have a working 2519 chip, so I used a "prosthesis" 6x4557 (SMD and DIP versions). Works flawlessly. "Prosthesis" is also used in the second copy. Instead of PROM, there is EPROM on a small PCB, similar for the 2513. It is quite convenient, because you can easily and cheaply test various modifications without wasting the precious 82S129 (etc).

The computers started up without any major problems, but I read a lot of valuable advice from this forum before getting them started. Thank you very much for that.

 

I invite you to view photos and a short film.

Short video

Best regards,

Mateusz / SQ9PXB

 

 

 

 

 

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Hey, Mateusz (SQ9PXB) !
Nice work! But your board has a twin brother. I started to look at the projects of the respected P-Lab a little more than a year ago, and during that time I integrated almost all his achievements into one of my early boards. When I started this experiment I didn't even understand why I was doing it, because all the rare components in Europe could be easily bought in the USA. But at the end of winter things have changed dramatically, and for me and my compatriots these projects became the only way to build a replica of the Apple-1. At the moment I installed on my board replacement 2513, 2519 (6xSMD HEF4557) as well as multi PROM's card with memory test of respected Uncle Bernie and usual WozMonitor, switching between them is done by simple rearrangement of jumpers. Not so long ago I started to build parts for my new Apple ][ Rev. 0 replica project, and at the same time I started to integrate LS chips into my experimental board. At the moment I have 3x74LS00, 74LS02, 74LS04, 74LS08, 2x74LS10, 74LS32, 4x74161 (except D15 position, which Mike Willegal correctly wrote in his Mimeo build manual for Apple-1), 74LS174, 74LS175 and 4x74LS257.) My goal is to build a working (but not very authentic) Apple-1 with a minimum of rare and expensive microchips for less than $250 (not including transformers, but with PS/2 keyboard adapter). In short, only from what you can buy on Aliexpress, now I can pay with my card only there. I have a couple of questions for you. You write that you successfully integrated DS0026 into your build, did you do a reliability mod of respected Uncle Bernie, I mean capacitors on the back of the board? Is your nickname on Aliexpress 2***r? Just before I buy, I read reviews and a guy from Poland with this nickname also buys components I'm interested in for the Apple-1. I am guided by the reviews, because buying from Aliexpress is always a bit of a lottery.
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Hi,Your workmanship looks

Hi,

Your workmanship looks beautiful.

I also do not want to build a computer that is identical to the original, although I try to reproduce it as faithfully as possible. Regarding the character generator chip, this is the "counterpart" of Tesla and RFT (unfortunately I don't remember their symbols), they have a different pinout, but they work.

As for the power supply - instead of the "original" ~ 12V transformer for the LM323K stabilizer, I used a ~7.5V transformer, so my stabilizer practically does not heat up. I don't have to worry about damaging it (and thus practically the entire computer). I recommend this solution instead of using ugly and noisy fans.

I saw Uncle Bernie's "reliability mod", and it is applied, but the computer works without it, too. I know from my electronic experience that these capacitors are necessary and I would use them that way. I see you have a slightly different version of the 6x4557 than mine - I like yours better.

On Aliexpress I was buying:

2513 - works

6502 - works (5 pcs), although it looks like a fake

MK4027 - does not work

AM1404APC from IC BOOM Store - from 10 pcs 8 works. (But immediately after my purchase, they increased the price 5 times)

MM1404 from another seller - did not work (the price was very low)

I bought a few AM1404APC (20 pcs) at https://www.yoycart.com/ at a sensational price of $ 2.4 apiece. They had several hundred pieces, but everything changes dramatically there, you have to search and ask.

Regards,

Mateusz / SQ9PXB

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Last seen: 12 hours 56 min ago
Joined: May 4 2021 - 06:35
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Hi there,IZ2FER here

Hi there,

IZ2FER here.

Excellent work, my congratulations!

 

Enjoy with it!

73, Claudio - P-LAB

 

PS If you wish, take a look at my projects ( https://p-l4b.github.io/ ), maybe you will find something you need! :-)

 

 

 

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