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Build Log : Apple 1 Replica

Discussion in 'Retro & Arcade Worklogs' started by aXLe, Apr 17, 2013.

  1. 2xCPU

    2xCPU Member

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    The chemistry of electrolytics is complex to say the least and they do age even without use. If you have a lab PSU, connect it with the voltage set near the rated voltage of the cap and current limited to a few tens of mA. Then leave it until the current drops to zero.
    The process is explained if you search for "reforming electrolytic caps"

    2.
     
    Last edited: Mar 19, 2016
  2. OP
    OP
    aXLe

    aXLe Member

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    Interesting - 5 minutes plus a minute for every month of storage works out to be about 7.6 hours in my case(!), though a 5300uF cap with a 30k resistor has a time constant of 159 seconds and should be fully charged at around 5 times that, which works out to be just over 13 minutes.

    My Sprague 5300uF measures at over 6500uF with the tester I have, and ESR of approx 0.060 ohms - pretty good considering the age - I might test it's time constant though to cross check the measured capacitance.
     
  3. OP
    OP
    aXLe

    aXLe Member

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    While waiting for other parts to arrive, I'm reforming the 5300uF cap.

    I started off at 10V with a 4700ohm resistor and measure leakage to be very low. I then upped the voltage to 15V with the same resistor and it all looks pretty good so far. Leakage is in the 10's of microamps from what I can see so far (measuring 10's of millivolts across the 4700ohm resistor.

    I'll leave it for another hour or so and take another reading but I think this 38 year old cap is fine :) It's new old stock so must have been stored well, plus its a quality brand.

    Thanks 2xCPU for the link on reforming. I found another couple of articles including a procedural manual by US department of defense on the matter. Interesting stuff, and at least I can be fairly confident it wont burst into flames when I fire it up for the first time (assuming I don't install it in reversed polarity of course!).
     
    Last edited: Apr 11, 2016
  4. OP
    OP
    aXLe

    aXLe Member

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    Did a full set of PROM's including ACI (Apple Cassette Interface) proms.

    Before :

    [​IMG]

    After :

    [​IMG]

    Again used steel wool to age them a little. These were originally Signetics 82S129 PROMS - it was very time consuming to remove the original markings. I had to lap them on a stone, then wet sand them to get the top flat and clean. The rest of the transfer process was ok - I tweaked my artwork and added the ACI proms to it.

    I think they look like decent replicas of the real deal :)
     
    Last edited: Oct 17, 2019
  5. OP
    OP
    aXLe

    aXLe Member

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    Some more parts thanks to Giuliano in Italy!

    First up the 2504's (7 of them) with date code week 22 of 1976 (ideally would like week 20!), a Signetics 74154 with date code week 7 of 1974 (ideally chasing a Fairchild part with date code 7604), and a 2519B with date code week 16 of 1973 :

    [​IMG]


    Next up, some salvaged BEL 100nF (0.1uF) ceramic caps of the era :


    [​IMG]

    Some of them look a bit chewed on, but they tested ok and will do until (IF) I can find others that are in better physical condition.

    Finally, some Philips 22uF 25V electolytics of the era :

    [​IMG]

    Pretty neat how Woz laid the 2504's out in 16 pin sockets with 2 chips per socket :

    [​IMG]

    In this pic you can also see the crystal I salvaged from an Atari PCB - week 20, 1975, and my 1975 555 timer (I'm still chasing a Fairchild part though) :

    [​IMG]

    Some of the BEL caps :

    [​IMG]

    The 2519 :

    [​IMG]

    Any finally an overview of where I am at present :

    [​IMG]

    I'm still chasing many parts including lots of Fairchild logic chips. I haven't even done my own proms yet - the last batch I did were in trade for some of the parts in this post, and I'm hoping to do a bit more of that type of trade :)
     
    Last edited: Oct 17, 2019
  6. nimmers

    nimmers Member

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    Loving this thread. Awesome job!
     
  7. OP
    OP
    aXLe

    aXLe Member

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    Some logic chips are on the way from Texas USA (thanks Richard!), including some that are EXACT date code matches with the originals :D

    I'm also getting a couple of 1980's plastic MOS 6502's - planning to take to one with a file/grinder(!) and a paintbrush and see what sort of replica I can make of the original white MOS 6502's - hopefully it will still work when I'm through with it! I'll be using the toner transfer process to do the markings, and will be making metal plates for the top of the chip. The filing/grinding is required to take the sharp edges off the packaging (the original white ceramic packages were quite organic looking on the edges - very rounded) and also to thin the packaging as much as I dare (stop when you see silicon - lol), as the ceramics are very thin.

    The MOS 6502 that I currently have is a later version of the chip than I'd like (it has a gold earth strap down the length of the chip that the early ones did not have) and the early ones are very rare now, so I'll try making one as see how it looks.

    PLUS, I've also located some AMI 6820 PIA's that are a far closer match to the original than the gold top ceramic Motorola one I have at present.

    I've also put feelers out on a couple of arcade forums as there are a couple of old arcade PCB's I know of that may be a good source of Fairchild logic chips, including Fairchild 555's.
     
    Last edited: Apr 14, 2016
  8. OP
    OP
    aXLe

    aXLe Member

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    Received some AMI PIA chips today :

    [​IMG]

    The grey AMI package is very close to the AMI one that was used on the originals - as always I'm chasing a closer date match (these ones are 1977), but I can always swap it out if I find a better one :)

    [​IMG]

    The white striped ceramic package is pretty interesting - as far as I know it was never used on the originals but looks pretty neat :

    [​IMG]

    I'll probably keep this one but it wont go on the board.

    Here is a shot with a black package 6800 cpu in the mix - you can see the contrast in colour with the grey AMI's :

    [​IMG]

    Cool :)

    More bits to arrive soon....
     
    Last edited: Oct 17, 2019
  9. OP
    OP
    aXLe

    aXLe Member

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    I received some parts from Richard in Texas USA :)

    Firstly some logic chips - four of them are exact part/date code matches with the original Apple 1's :

    [​IMG]

    LM320MP voltage regulator - same manufacturer markings and shape as the originals (later datecode though) :

    [​IMG]

    And a couple of 80's MOS 6502's to hack up and see if I can make a decent replica of a white MOS 6502 (pre the one that I have) :

    [​IMG]

    Installed :

    7410 at board position C6 (I have a 9N10/7410 for this position as a spare - seems some originals used either or):

    [​IMG]

    9N10/7410 at position B2 :

    [​IMG]

    7402 :

    [​IMG]

    One of the 7400's (date code match) :

    [​IMG]

    8T97B's (date code match) :

    [​IMG]

    LM320MP -5V regulator :

    [​IMG]

    [​IMG]


    Starting to feel like I'm getting somewhere with the logic chips now - still a number to go, but making headway....

    [​IMG]

    Fairchild logic chips still required - let me know if you can help :) :

    74160
    9316 x 5
    7404
    9N27/7427
    74174
    7451
    7432
    7408
    74175
    74123
    74S257 x 4 (ceramic package)
     
    Last edited: Oct 17, 2019
  10. dc99

    dc99 Member

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    Great job!

    I'll check my vintage parts collection to see if I have any of the missing IC's.

    Cheers
     
  11. Nitephyre

    Nitephyre Member

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    The dedication to this is just as crazy as Baz the Iron Man :shock:
     
  12. MUTMAN

    MUTMAN Member

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    awesome would be getting woz to sign the board and switch it on.
    he lives in aus these days, so its not that mad of a thought
     
  13. Nitephyre

    Nitephyre Member

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    Hey now that's a thought... he'd probably even have the hookups to get parts :Pirate:
     
  14. MUTMAN

    MUTMAN Member

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    even if it 'blew magic smoke' when Woz turned it on, it'd be epic :eek:

    someone facebook Woz please
     
  15. pfrcom

    pfrcom Member

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  16. @rt

    @rt Member

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  17. OP
    OP
    aXLe

    aXLe Member

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    Hehe - be interesting to see what it goes for - eBay is probably not the best place to sell these things - I'm sure they would get a lot more at an auction house like Sothebys.

    This is a NTI board which is later than the version I am building and uses mostly Signetics chips where I am using Fairchild.
     
  18. @rt

    @rt Member

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    Ok, I saw the white (ceramic?) chip and assumed the boards were the same.
    That would be a ripoff if it’s not even the right chips :D
     
  19. macplus

    macplus Member

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    Axle has got me hooked now too on building a replica! I am cheating a little by getting the whole kit. I hope to replace a few of the components with nicer ones as I go.

    Have to sort out a keyboard and power supply too. Got the cassette interface for loading stuff.

    [​IMG]


    [​IMG]
     
  20. OP
    OP
    aXLe

    aXLe Member

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    good stuff :)

    You will certainly finish that before I finish mine! I've stalled again on my build - I'll have to push on with it again. Not too many more parts to find really.
     

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