the alpha syntauri system    Page No.:H212-10
 
          The story about the Apple Seed Clone Cards
    of the Mountain Computer Music System
 
     
Several weeks ago i recieved an email from a friend with attached pictures of bare PCB´s. After short examination it turned out to be a set of 2 clone PCB´s of the Mountain Computer Music system manufactured by Apple Seed - a group of enthusiasts that reverse engineered in former days a lot of common interface cards and located in Ontario in Canada. They had even in that days a catalog of that clone cards with the listings of the components for assembly of that cards.

I really got excited when i faced that pictures because the y permitted me to also view several traces that have formerly not been detected that well below of the circuit sockets and some of the components. Because my friend asked me for assistance by assembly of the cards i was glad to accept and offer him my time for the assembly.

After the bare PCB´s arrived in my place i immediatly first scanned the PCB´s front and reaar side with high resolution for archieving purpose.
Here are the scans:

Digital Card Component side:
 

Digital Card Solderside:

Analog Card Component side:

and the Analog Card soldering side:


After that i started inspecting my dungeaons of components to detect the parts still missing for the assembly. In general most of the parts are still rather common LS logic and standard components but some parts turned out to be really obsolete and rather more difficult to purchase.
Among the obsolete parts are: 2x NE5008 compression/decompresion chip ( still availiable ),  1 x DM813 bus transciever (rather more difficult to find ), 1x AM6080 AD conversion chip ( you must pay attention about faked IC´s ), 3x P2111A static RAM  ( also rather difficult to get )  and most difficult to find the phototransistor MRD370 ( this really turned out to be the most difficult hunt ).

After finally i had recieved my purchases from across the world ( AM6080 from Hong Kong ) DM8131 and P2111A from Recyclers in USA and the MRD370 as new unused sparepart from Spain i started with the task of the assembly.

First of all i started to make a clone of the lightpen. Here is a sketch of the assembly:

I used a empty case of a permanent marker, soldered the phototransistor to the thin cable and covered the pins with shrinking hose and then
i put the cable through the rear stomp of that permanent marker an fixed that cabel also with shrinking hose that way that enough cable was
remaining in the case of the permanent marker so in case of malfunction the phototransistor could be pulled of towards the front of the tip and
some of the cable still there long enough for desoldering the transistor and replacing the device and pushing it back to the tip of that case and
fix again with shrinking hose to the case. In front of the lense of the transistor is a tiny aluminium tube to focus the lens. and the transistor is
fixed in place with small drop od superglue.

Next i populated the digital Interface card of the MCMS system:

and next i assembled the analog card of the MCMS system:

Like i explained in previous pages the connection used at the original cards of the MCMS system are of flexible foil cable and though being
more flexible the weakness of the material by time ageing leads to non-reliable contact. Therefor i prefer and use instead hard long goldplated pins.
The disadvantege is that this connection is less felxible and need quite rough bending to fit to the different hights of that both cards.<
The next picture explains that fact of the different heights, which is at the clone cards even more extended than at the original cards:

   
 
  Here is a view to the soldering side of the analog card after attaching and fixing the cables with cablebinder:
       
     
Important Hint:
The Apple Seed PCB´s have some severe mistakes that you must bear in mind while performing the assembly:
At the digital card  two contact through holes are missing and that traces from topside must be contacted with the traces at the
solder side by drilling and soldering at both sides see marks below.
And at some points the holes are rather dangerous to neighbor contacts. That spots also have been marked.

 

And also at the Analog board there is a drilling hole missing and must be added and the component must be soldered at both sides
to ensure contact to both sides:
 


 

 
       
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