DarrenF
Well-known member
So I accept that my inexpensive EPROM programmer isn't going to program bi-polar PROMs. But I want to be able to *READ* them, so I'm only ordering ones that are actually bad.
Attached is a photo of the adapter I built installed on the reader. Wiring is straightforward; I pulled up pinout for the 82S123 & a regular 2716. The 8 data lines were connected respectively, and the 5 address lines that the 82S123 has were connected to A0-A4 of the 2716. The rest of the address line were left unconnected (the GQ-4X doesn't care about unconnected address lines). And of course Vcc and Vss (GND) were connected.
I put in a PROM (in this case, one from Taito Grand Champion) and just read it as a 2716. Of course I end up with the same data (the 32 bytes in the PROM) over and over (64 times, to be exact). No big deal, as there are only 32 bytes, I can just compare them manually to the correct contents of the PROM (from MAME). Screenshot of read attached also.
I intend to also build one for the other most common PROM I see, 82S129 (256x4).
Attached is a photo of the adapter I built installed on the reader. Wiring is straightforward; I pulled up pinout for the 82S123 & a regular 2716. The 8 data lines were connected respectively, and the 5 address lines that the 82S123 has were connected to A0-A4 of the 2716. The rest of the address line were left unconnected (the GQ-4X doesn't care about unconnected address lines). And of course Vcc and Vss (GND) were connected.
I put in a PROM (in this case, one from Taito Grand Champion) and just read it as a 2716. Of course I end up with the same data (the 32 bytes in the PROM) over and over (64 times, to be exact). No big deal, as there are only 32 bytes, I can just compare them manually to the correct contents of the PROM (from MAME). Screenshot of read attached also.
I intend to also build one for the other most common PROM I see, 82S129 (256x4).
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