Looking for manual/schematics for Microangelo MA520 S-100 card

[Dan Roganti]

Chuck Guzis wrote:
> On 1 Apr 2009 at 19:43, Dan Roganti wrote:
>
>   
>> That photo really helps - I somehow overlooked that link - thanks ! I
>> contacted the web owner there too in case he might have one. So I'm
>> still on the lookout. 
>>     
>
> What struck me about the chip at U5 is that it's a DM7490AN, not an 
> LS90.  (or even an S90 or F90).  I wonder if this was intentional or 
> what was simply on hand
>   

I'm not sure yet, but it's not the first time-- I see this in many of 
the early stuff that I work on. I always keep a bunch of the 7490 in my 
parts bin - just in case- . But what's also strange is that his photo is 
missing Q1, Q2 while the resistors are still onboard--because it's 
connected to J15, which pins 1,2 are normally connected via a small 
trace(difficult to distinguish in the photo)  Plus mine has a mod with 
another 2 transistors wired into the pads of connector JC from U3 and U4 
to connector JB.
So I hope I can decipher this once I find the manual.

=Dan

[ = http://www2.applegate.org/~ragooman/   ]