the MIMEO  - assembly and story    Page No.:A05

  As explained in the Apple-1 page there have been only 250 mainboards made from the Apple-1 and that amount had been split in two runs, of which the
  first run consisted of 100 pieces ( later called the "preNTI-version ) and the second run - which had been made by the NTI-company and that models from
  the second run have been called later the "NTI-version" of the Apple 1.

  Allthough the layout of the leads and traces havenīt been changed in that second run, the assembly and the used components did slightly differ from the
  earlier "preNTI-version". In main the decoupling capacitors on the second run have been more modern multilayer capacitors, while in the first run "old-
  fashioned" ceramic disccapacitors have been used. Another change in assembly had been, that the majority of the "pre-NTI" boards still had been populated
  with the white ceramic version of the 6502 CPU and the violett ceramic version of the 6820 PIA while in the later NTI-version nearly only the CPU and PIA
  with the plastic-case had been used. And in the later NTI-version there have been different kinds of small electrolytic capacitors used ( ones in yellow
  cases instead of the blue cased ones that have been only used in the "pre-NTI version".

  But the very first remarkable difference to common users had been the fact that NTI set itīs factory logo below the label from Apple Computer - a diamond
  square with the letters NTI inside of it.

         Differences between "pre-NTI" version Newton 1 and the "NTI"-version of the Newton NTI board if populated like original Apple-1

  "pre-NTI" version MIMEO   "NTI"-version of the Newton NTI
  ceramic CPU and PIA    plastic CPU and PIA
  ceramic disc decoupling capacitors   multilayer ceramic decoupling capacitors
  blue electrolytic capacitors   yellow electrolytic capacitors

   a remark to the pictures above: the different shades of green silkscreen on the boards is partially also caused by dirt or bleaching of the sun !

  But the very first remarkable difference to common users had been the fact that NTI set itīs factory logo below the label from Apple Computer - a diamond
  square with the letters NTI inside of it.

  here the Newton-1 board without the NTI-logo   and here the Newton NTI board with the NTI-logo

  The MIMEO is ( similar to the Newton1 ) a replication of the "pre-NTI version" of the Apple-1 out from the first run. The reproduction of the mainboard was
  carried out by Mike Willegal. In fact it seems to me that the manufacturing of the Newton1 was a reaction to the fact that after Mike Willegal had made his ī
  first limited edition of the MIMEO ( which was also a reproduction of the pre-NTI version of the Apple-1 ) and that boards had been sold out after very short
  period of time and then for a long period the community of Apple freaks had been quite a while waiting - the Newton1 had been made to solve the still not
  completely satisfied complaints on more replications of the Apple-1 mainboard. In the meantime Mike Willegal had quite a list of people waiting and
  has released a new run of the MIMEO. 

  When i decided to assemble a replication of the Apple-1 there were no boards availiable - so i decided to stay on the list from Mike Willegal, because he was
  already collecting emails from persons wanting a board an it was presumable that a new release would occur within reasonable time. In the meantime i started
  collecting information on the board and the history of the Apple-1 as well as its technical details.

  While collecting the technical details and reading about the tasks performed with the Apple-1 i compared it with my detailed knowledge on the Apple II. I have a
  collection of the entire series of Apple II from early ones sold in Europe till up to the Apple IIGS Rom 3 version. Up to my mind the limitations of the Apple-1 had
  been in majority a result from the fact that only few had been sold and that in very short time this model had been resigned by itīs followup - the Apple II.
  If more of the Apple-1 would have been sold and if the Apple II would not have been introduced that fast to the market - itīs my deep believe that there would
  have been more expansions developed for the Apple-1. There would have been made a RAM-expandsioncard availiable and a slotexpansion card to expand the
  Apple-1 with at least another 2 slots. The development of such expansions was burried by the invention and the introduction of the Apple II that had this
  additional capabilities. The 8 slots and the expandability of the RAM in the Apple II removed this disabilities of the Apple-1 and gave the Apple II a giant leap
  ahead in the development of personal computers.

  But anyhow i decided to make a step back to that time of the end of the seventies and to develop the "missing expansions" that have not been made in those
  days and  by that to permit the Apple-1 to participate from the same success that later was granted to the Apple II. So at the same day the boards arrived in my
  home and i started hunting for the parts for the assembly i also started with the development of the "missing links" and besides started the development of the
  slotexpansioncard, a RAMexpansion card and after few more days i also thought it to be a good idea to make a ROMexpansioncard, that would permit to make
  basic in Eprom resident and saving time from loading basic from tape. And because i always enjoyed making experiments with Apple II and some kind
  of prototype card i thought it might also be a nice idea to make a prototypecard for the Apple-1 too.

  In the meantime i had read all past thread related to the Apple-1 replicas and the difficulties about getting the parts for that board. Next i contacted Unicorn
  electronics, the company recommended by Mike Willegal , and claimed to offer a complete set of parts for assembly.... and they answered me that a lot of the
  parts in the set would be quite more modern than the parts used in the original Apple-1. While on the hunt for parts i learned a lot about the difficulties
  related to spotting of old obsolete parts from postings of corey986 at applefritter and rather soon i had to make several experiences of the same kind.

  I canīt tell much about the market on obsolete parts in the USA or Canada, but here in Europe i had to learn that laws released by European Commision
  áffect national laws pretty much and that sometimes such kind of laws are made from representatives that have less knowledge upon the results that
  kind of regulations cause, than a bull knows about nuclear physics..... the results sometimes turnout strange effects, that cause the opposite of that what
  regulation was made for.

  For example in Europe the regulations to protect environment require that only specialized companies are permitted to carry recycling business and that
  the aim should be to reach the target that electronic waste is to be recycled in a correct manner protecting the environment.

  Therefore if you enter at a Junkyard and ask if you may pick up some of the dumped electronics, because you want to extract some obsolete parts and want to
  reuse that parts - the access to the dumped items is refused - and the electronic waste is locked up..... but instead of recycling the trash, they fill the stuff in
  containers and ship / export that electronic waste to Ghana in Africa, where that junk is dumped to illegal junkyards and small children burn the trash in open
  fires without any health protection and pickup the rest of metal left after burning - but before - while burning - exploiting dangerous and absolute toxic gases in 
  the entire area and poisoning the entire area with stuff like dioxin and other lethal poisons. In the meantime in the area around Acra and the river close to Acra
  the environment has been totally damaged and poisoned. That is exactly the opposite of the aim of the former regulation. The regulation is totally perverted.

  Just to give a short summary here a short overview of the current status on the obsolete parts if you try to find / get them ( valued in 2 classifications -
  just getting the part itself with correct datestamp or replacing it with more modern part )


  part from partlist   the part itself with nearly correct datestamp   replacing it with more modern part ( later tha 1980 )
  ceramic 6502   last sell at ebay 750,00 U.S.Dollars   not easy
  ceramic 6820   very difficult   not easy
  yellow spectrol 150 Ohm trimmer   impossible   difficult
  8 pin TI socket   very difficult   difficult
  14 pin TI socket   very difficult   difficult
  16 pin TI socket   very difficult   difficult
  24 pin TI socket   nearly impossible   difficult
  40 pin TI socket   nearly impossible   difficult
  Mk4096 RAM chip   rather expensive   not easy
  DS0025 clockpulse-amp   very expensive ( i had to pay nearly 48 U.S. Dollars )   difficult
  2504A shiftregister   difficult   not easy
  2519 shiftregister   difficult   not easy
  2513 Character ROM   very difficult   very difficult
  7450   rare and difficult   difficult
  7427   difficult   difficult
  74157   not easy    
  74160   not easy    
  74161   not easy    
  74166   not easy    
  74S257   not easy    
  8T97   not easy    
  "old fashioned" carbon resistors   difficult   not easy
  14,318 Mhz clockcrystal   extreme rare and difficult   difficult
  LM323K "Goldcap" TO3 case
5 V regulator
  impossible   difficult
  Correct AVID coolingsink   very difficult   difficult
  5300 ĩF capacitor   very expensive   not easy
  2500 ĩF capacitor   very expensive   not easy
  305-044-521-201  44pin edgeconnector   very difficult   rather difficult
  MMI 3601   extreme difficult ( only 1 source for programmed ones )   very difficult
  MR500/A14F 3A rectifier diodes   rather difficult    
  MPS 3704   rare   not easy

  scale of difficulty:

  not easy rare difficult very expensive extreme rare very difficult nearly impossible impossible

  Just to give an impression - i needed more than 6 months to get rather close to the original and i spent more than 1500,00 U.S. Dollars to get 
  at least quite closer than if i would have purchased the parts-set from Unicorn electronics .... starting with the fact, that my boards are populated
  with the correct TI-sockets..... and the carbon resistors in "old fashioned" case ( with "cut-off ends" instead of the rounded ends normal today ).

  here is a view to the MIMEO board with the "on board" components soldered only:

  During the months i have been hunting for the parts the most difficult parts turned out to me to be the edgeconnector, the DS0025 and the clockcrystal.
  in that period Michael Ng announced that he would launch the manufacturing of the Newton NTI board. Because i knew that all other replications had
  been made from the "pre-NTI" Apple-1 i immediatly enlisted myself for one of this boards. It will permit me to build up the second version of replication
  and then offer to me the possibility to compare both boards with eachother. And after all because i decided to develop also some expansionboards, it
  would permit me to test this expansionboards on two slightly different systems.

  In the beginning when the bare PCB of the MIMEO arrived i intended to build  the replication in "old fashioned style" meaning that i intended to make
  a wooden case like it was done by most of the owner of an original Apple-1. In the mid of December 2012 ( short after i enlisted for the Newton NTI )
  i also recieved an invitation to take part in the Vintage Computer Festival Europe at the end of April 2013. Quite close in that time in December Corey986
  published his contribution at applefritter about making a transparent case for his MIMEO. Although the wooden case had been prepared allready,
  i decided to delay this kind wooden case and switched my mind to instead also make a transparent case for the Vintage Computer Festival and by that
  enable the visitors to get a complete view to the entire Board from every angle of view. If i would build both boards in Lexan-cases it would give the
  visitors of the VCFe the chance to carefully compare both boards and also it would permit to display a piece of histors that the Apple-1 was not only
  a single first personal computer - but even that this very first piece consisted of two different kinds of versions. The previously planned wooden case
  would have looked like that:


    At that stage of assembly the board still had the wrong video level adjust resistor and the wrong rectifier diodes for the 5 volt branch. In the following months
    while getting parts that fitted closer to the original i started to change "just working" parts against "nearly close to original" parts and i started to make a
    transparent lexancase.


  While designing the lexancase i also decided to calculate the space required to integrate the slotexpansioncard that i started planning also in December
  and to present the expansioncards, if possible ( - and if the new designed expansioncards could be completed in that short period of time ) at the VCFe too.

  At that time i already had replaced the video level adjust resistor and the rectifier diodes in the 5 Volt branch. It was also clear that it would never be possible to  
  receive, assemble and complete the ordered Datanetics keyboard and therefor i was forced to use another keyboard and modify the connection to march with
  the requirements of an Apple-1. It was at this point also clear that i would need to use transformers for European power source of 220 Volt.


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