[abc80] Super Smartaid Cartridge

Anders Sandahl anders at abc80.net
Ons Apr 24 12:01:46 PDT 2019


For all curious people:

The 82s131 is dumped as well! It was a little project to unsolder the PROM
but everything went well. No smartaid was injured during the process!


> On 4/23/19 12:46 PM, Anders Sandahl wrote:
>> I'll bet that all the circuits turns out to be the same as on the magnum
>> version. The board it self looks the same, the patches are different.
>> Different sizes on one of the ERPOM's and a piggybacked 74ls74 on one
>> place.
> Right, 27128 = 16Kx8. The extra 74LS74 (dual D flip flip) is presumably
> used for the extra address pins, which, together with the blue wires and
> "SUPER" marking, very much supports the idea that it is largely the same
> board, although it seems to be a different version: the lines are
> clearer, and the alignment of the larger EPROM has changed.
> Well, this makes it easier...
> N82S131 is a bipolar prom (512x4), which probably indicates that, just
> like ABC80 itself, it uses a PROM for address decoding. Reading out this
> PROM is going to be important.
> I'm amused at seeing a single 74HC IC on that board, a 74HC32. It's not
> even a TTL-compatible 74HCT (74HC can drive TTL, but not the other way
> around -- at least not reliably -- unless Vdd is reduced sufficiently.)
> I am guessing it is a simple drop-in mistake and that it worked well
> enough; the circuit is a quad OR gate and it must get its inputs from
> somewhere...
> MB8416A is just Fujitsu's part number for an 6116 SRAM.
> 	-hpa

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