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Conversion to 9825T
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Conversion to 9825T

I got two board from Paul Berger on the vinthp mailing list which would convert the 9825A to an 9825T:

  • The A24 (09825-66524) Ebenezer board containing RAM and a ROM set
  • The A25 (09825-66525) SKOAL board

To update the machine first remove the System ROM pack from the 9825A, then cut a few traces on the CPU board:

The CPU board, 09825-66517, with the two-way switch and the traces that have to be cut in the middle of the picture.
The CPU board, 09825-66517, with the two-way switch and the traces that have to be cut in the middle of the picture.

Installation pictures from CuriousMarc’s video

Ebenezer board (1st above the tape drive board)

From CuriousMarc's video: the Ebenezer board fitted above the tape drive board, with the original stack lying alongside.
From CuriousMarc's video: the Ebenezer board fitted above the tape drive board, with the original stack lying alongside.

followed by the Skoal board. I lacked the nice HP spacers for that so I used some nylon spacers and screwed them in:

The Skoal board added on top, seen edge on, mounted on nylon spacers instead of the HP originals.
The Skoal board added on top, seen edge on, mounted on nylon spacers instead of the HP originals.
The same stack from above, with the ribbon from the Skoal board running across to the interface board on the right.
The same stack from above, with the ribbon from the Skoal board running across to the interface board on the right.
Last modified: 2026/09/06
© 2024 by Frits Jalvingh. All information in here can be freely used (MIT License)