HP 25C


Problem with HP25C.
Calculating is o.k. Prgramming not o.k.
I can try to programm the HP25C.
Every step, done by sst, in programming gives the following:

step #1 f prgm 00
step #2 01 13 00
step #3 02 13 00
step # 49 13 00

It does not matter what keystrokes I give.
Who has the solution for this problem ????


You RAM chip is bad. Only source is another machine. You may be able to use a RAM chip from a 29C. Also some 25C machines use two RAM chips. You have to add a resistor to use a single chip device in a two chip machine.


I have found 6 Chips ( IC ) in my HP 25C.

Is there someone who can sum up the functionality of every independent chip ?? Where can I find that kind of information ??


The smaller chip under the display module is the ROM0/anode driver chip. The larger one is the cathode driver. The big, wide chip at the bottom of the circuit board is the ACT chip (the CPU). The one to the left of it is a ROM chip. The other two (the ones above and to the right of the ACT) are RAM chips.

Possibly Related Threads...
Thread Author Replies Views Last Post
  HP-25/25C Potential Matt Agajanian 14 951 07-17-2013, 02:57 AM
Last Post: Matt Agajanian
  Later HP-25C Keyboard Repair aj04062 2 295 04-23-2013, 07:25 PM
Last Post: aj04062
  For sale: HP 25C and Stat Pac 2 for HP 65 Michae Altmann 1 275 04-21-2013, 01:24 PM
Last Post: Raymond Del Tondo
  25C rememberss data only Matt Agajanian 7 490 04-15-2012, 08:36 PM
Last Post: Matt Agajanian
  29C/25C question. Matt Agajanian 7 412 04-03-2012, 12:03 AM
Last Post: Matt Agajanian
  Paint job (not for a car but for my 25C) Matt Agajanian 0 164 04-02-2012, 04:20 PM
Last Post: Matt Agajanian
  HP-25C Repairing aj04062 11 697 10-31-2011, 01:11 PM
Last Post: Randy
  Difference in design for 25 and 25c exschr 2 240 07-04-2011, 04:36 PM
Last Post: exschr
  HP 25c Apps Review: GO 25 SCI, rpn 25 Eddie W. Shore 14 840 03-29-2011, 05:10 PM
Last Post: Andrés C. Rodríguez (Argentina)
  GO-25 An HP-25C Emulator for the iPod and iPad Namir 12 656 03-23-2011, 10:38 AM
Last Post: Walter B

Forum Jump: