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Author Topic: Extraneous item identification... (Read 729 times)

Offline Pluto63

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Extraneous item identification...
« on: 2021.October.14. 16:43:13 »
Hi guys it’s a serious post ...

I’ve opened my newly acquired ep128 to do some maintenance, fixed a keyboard contact on the membrane, installing a 2.4 exos eprom and some contact cleaning on the edge for my newly build disk drive interface (thanks to Pear for all info and schematics).
Now at some point this thing on the foto dropped from somewhere, is this some sort of factory patch or user work, just to put it back for originality.
Thank you.

Offline Zozosoft

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Re: Extraneous item identification...
« Reply #1 on: 2021.October.14. 20:25:08 »
It is part of the German version EP128. It is connect the GND from the modulator metal case to the RF shield (inside silver painting of computer case. It is only at German machines, because more serious RF noise emission standards in Germany.)
27937-027939-1

Just for the EP statistics: what is the S/N of your machine?

Offline Pluto63

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Re: Extraneous item identification...
« Reply #2 on: 2021.October.15. 11:04:12 »
Here is the serial number, one more question.
I have the 03-07 cartridge with basic and German keyboard 128 EPROMs, i modded it as from your schematic to use 256 eprom and transfer the exdos eprom from the dd interface in place of basic to use the extra ram option on it and it works perfectly, I now have 512k ram. Will this mode allow also to use 512 EPROMs?
Thank you

Ps. Never mind just saw pin 1 a15 is on vcc so clearly no, ha ha
« Last Edit: 2021.October.15. 11:15:31 by Pluto63 »

Offline Zozosoft

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Re: Extraneous item identification...
« Reply #3 on: 2021.October.15. 11:42:42 »
Here is the serial number
Thanks!

Quote
Will this mode allow also to use 512 EPROMs?

Ps. Never mind just saw pin 1 a15 is on vcc so clearly no, ha ha
It is can be hacked, but the main problem are: only 64K address space at cartridge. Then using 27512 optimal only in one socket cartridges.
Long time ago I made 2x64K hack on one machine, but it is need new address decoder in the machine, for decoding 128K address space, and also wiring A16 to the cartridge port (I replaced the signal on B3 pin).