Hand Held Products 71M/M eprom carrier question
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06-17-2020, 02:47 PM
Post: #13
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RE: Hand Held Products 71M/M eprom carrier question
The common connection from the top lead of the transistors to the top right lead of the IC socket (pin 28) channels +5V to the transistors, which act like switches on it; it would be interesting to see where the bottom pins of the transistors go. The second pin from the top on the right side of the IC socket (pin 27) is A14 in 32K and 64K EPROMs, but it is (PGM)' in a 16K EPROM and it should be kept high in such an EPROM.
It would also be interesting to see where pin 1, the top left one (A15 in a 64K chip, VPP in 32K and 16K chips) goes. |
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