HP Portable Plus - ROMBO 128 KB EPROMS?
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07-20-2020, 07:28 AM
(This post was last modified: 10-31-2021 06:53 PM by Martin Hepperle.)
Post: #3
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RE: HP Portable Plus - ROMBO 128 KB EPROMS?
I figured that I only need these connections:
Code: from to Code: VPP 1 n.c. or ground? The jumpers (A) and (B) control how the address lines A15 ad A16 are connected to the ROM/EPROMs. All in position (A) direct A15 and A16 to the socket pins A15 resp. OE/. This is the same setting as used for the 64 KByte EPROMs. I have to evaluate whether a 27C1001 on a PCB still fits the space before resorting to some PLCC chip. Maybe for starting some lifted pins and flying wires are o.k., but not nice for repeated EPROM programming. Chip pinouts: Code:
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Messages In This Thread |
HP Portable Plus - ROMBO 128 KB EPROMS? - Martin Hepperle - 07-19-2020, 08:34 AM
RE: HP Portable Plus - ROMBO 128 KB EPROMS? - Dave Frederickson - 07-19-2020, 04:54 PM
RE: HP Portable Plus - ROMBO 128 KB EPROMS? - Martin Hepperle - 07-20-2020 07:28 AM
RE: HP Portable Plus - ROMBO 128 KB EPROMS? - Brian Hudson - 02-06-2021, 03:31 PM
RE: HP Portable Plus - ROMBO 128 KB EPROMS? - Martin Hepperle - 10-31-2021, 06:52 PM
RE: HP Portable Plus - ROMBO 128 KB EPROMS? - Dave Frederickson - 11-04-2021, 01:26 PM
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