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HP-25 resurection project
12-15-2020, 12:23 PM (This post was last modified: 12-15-2020 12:40 PM by wbvreeuwijk.)
Post: #8
RE: HP-25 resurection project
So I removed all components from the board and will start populating it. First with the PSU section. I did find out why there was a difference between other HP-25 boards and mine. It seems that the Vdisp is taken from Vss through a resistor. This explains the missing part.
   

Also I had a first go at creating the LED display
   

It's working, but the digits are in the wrong order and the height of the board is a bit to small, so next revision has been ordered.

Panamatik suggested to place the ROM/RAM and ACT in IC sockets, which I hadn't considered yet. Parts should be arriving this week.

35 | 45 | 55 | 65 | 10 | 19C | 21 | 25 | 29C | 34E Ir | 41C | 33E | 33C | 34C | 67 | 41CV | 41CX | 71B | 75B | 10C | 11C | 12C | 15C | 16C | 41CL | DM41X | DM16L
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Messages In This Thread
HP-25 resurection project - wbvreeuwijk - 12-01-2020, 10:44 AM
RE: HP-25 resurection project - cjmcc - 12-03-2020, 04:27 PM
RE: HP-25 resurection project - AndiGer - 12-03-2020, 06:31 PM
RE: HP-25 resurection project - wbvreeuwijk - 12-15-2020 12:23 PM



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