[Coco] Re: Color Computer 3 prototype

[jdaggett at gate.net]

Torsten

I can suggest a possible reason. 

1) the board is labeled with 7 IC patterns as Spare 1 thru spare 7. 
What t hey did is lay down a IC pattern to solder in a IC or a socket 
and then use wire wrap to connect to the rest of the circuit. This is 
feeble attempt to make a breadbord area. Four of the seven spare 
IC slots are used and two of them are PAL chips that are labeled 
"INT". My guess is that these chips contain the logic to implement 
the IRQ and FIRQ routining as determined by the registers at 
$FF92/3.

2) In doing all softwre test boards sometimes the schematic has to 
change because it makes the software easier to do. When doing a 
project like this there are compromises in the hardware and 
software. And the debate as to whiat should be done where. This 
often causes a PCB changes and instead of doing a new board, cut 
runners and use wire wrap.

been there done that all too many times. One software test board I 
did went through three passes to finally get something that looked 
decent and was usable. All because of h ardware changes 
requested by the software group. 

james


On 21 Jan 2005 at 16:32, Torsten Dittel wrote:

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From:           	Torsten Dittel <Torsten at Dittel.info>
Date sent:      	Fri, 21 Jan 2005 16:32:45 +0100
Subject:        	[Coco] Re: Color Computer 3 prototype
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> This is weird. Why should they have solderd them in? The board looks
> to be in an early state (with so much wire wrapping). Perhaps to avoid
> faults by bad contacts?