Last year ( July 16th ) mr. David Smith give the solution for my HP25-C. Broken C-MOS type 7626 HP indication( 1820-1630 ).
Where can I obtain the C-MOS ?? Are there replacements ?
For me it is a challenge to repair the HP25-C myself.
Louis.
HP25-C
|
02-09-2005, 04:59 AM
Last year ( July 16th ) mr. David Smith give the solution for my HP25-C. Broken C-MOS type 7626 HP indication( 1820-1630 ).
Where can I obtain the C-MOS ?? Are there replacements ?
02-09-2005, 04:01 PM
The only source of the chips is another machine. You can find compatible chips in the HP25C or HP29C. The 25C had two types... a two RAM chip version or a single RAM (double capacity) chip version. Since the 29C has much more memory than the 25C, it used two of the double capacity chips. Now the tricky part... there is a slight difference in using the two types of chips. There is a 100K pull-up resistor on one of the RAM chip pins (sorry, I don't remember which version uses the resistor and which does not). If you change RAM chip types in your machine you will need to either add or remove the resistor. |
« Next Oldest | Next Newest »
|
Possibly Related Threads… | |||||
Thread | Author | Replies | Views | Last Post | |
HP25 Programming Failure | MikeG | 1 | 961 |
05-05-2007, 01:54 PM Last Post: Randy |
|
Value of HP25? | John Polhemus | 3 | 1,080 |
02-06-2007, 03:56 PM Last Post: Thomas Okken |
|
reparation HP25 french | pou | 4 | 1,633 |
01-02-2007, 04:41 AM Last Post: Olivier TREGER |
|
What's wrong with my HP25? | Karen | 2 | 1,001 |
11-04-2006, 03:29 PM Last Post: Randy |
|
HP25 problem at revival | Alain Delmotte | 4 | 1,290 |
02-19-2006, 09:40 PM Last Post: John Garza |
|
HP25 Memory | Grahame Sutherland(Scotland) | 15 | 3,553 |
12-09-2005, 05:02 AM Last Post: Grahame Sutherland(Scotland) |
|
HP25 without or with polar coordinate bug more valuable ? | Bernhard | 1 | 880 |
10-30-2005, 08:36 PM Last Post: David Smith |
|
HP25, HP65, HP67 and HP41 emulators | Alvaro Gerardo Suarez | 0 | 687 |
05-25-2005, 12:05 AM Last Post: Alvaro Gerardo Suarez |
|
HP25 PROBLEM | JULIO PONCE | 4 | 1,322 |
04-24-2005, 01:56 PM Last Post: Andrés C. Rodríguez (Argentina) |
|
hp25 on/off switch | thaddeus boruta | 14 | 3,110 |
04-21-2004, 02:25 PM Last Post: Jon |