HP25C repair, help needed

Threaded Mode | Linear Mode

HP25C repair, help needed

01-16-2019, 12:21 PM

Post: #8

Didier Lachieze Offline

Senior Member

Posts: 1,625
Joined: Dec 2013

RE: HP25C repair, help needed

(01-16-2019 11:54 AM)albertofenini Wrote: it looks like our is missing an IC, just above the ACT chip.
Is that possible ?

According to the very useful HP Calculator Chips table, there are two types of RAM chips for the 25C:

single density (1820-1630 or 1820-1843 - 8*56).
double density (1820-1886 or 5061-0469 - 16*56)

The board above has two single density 1820-1630 RAM chips. So if you have a double density RAM chip on your board it's normal to have only one RAM chip.

« Next Oldest | Next Newest »

Messages In This Thread

HP25C repair, help needed - albertofenini - 01-15-2019, 09:24 PM

RE: HP25C repair, help needed - albertofenini - 01-15-2019, 09:53 PM

RE: HP25C repair, help needed - teenix - 01-16-2019, 11:49 AM

RE: HP25C repair, help needed - teenix - 01-16-2019, 11:37 AM

RE: HP25C repair, help needed - teenix - 01-16-2019, 11:39 AM

RE: HP25C repair, help needed - AndiGer - 01-18-2019, 05:51 PM

RE: HP25C repair, help needed - Didier Lachieze - 01-16-2019, 11:46 AM

RE: HP25C repair, help needed - albertofenini - 01-16-2019, 11:54 AM

RE: HP25C repair, help needed - Didier Lachieze - 01-16-2019 12:21 PM

RE: HP25C repair, help needed - albertofenini - 01-16-2019, 01:55 PM

RE: HP25C repair, help needed - albertofenini - 01-16-2019, 09:55 PM

RE: HP25C repair, help needed - teenix - 01-17-2019, 01:04 AM

RE: HP25C repair, help needed - hewlpac - 01-16-2019, 10:35 PM

RE: HP25C repair, help needed - albertofenini - 01-17-2019, 12:08 AM

RE: HP25C repair, help needed - jebem - 01-17-2019, 08:29 PM

RE: HP25C repair, help needed - albertofenini - 01-17-2019, 02:59 PM

RE: HP25C repair, help needed - teenix - 01-17-2019, 05:39 PM

RE: HP25C repair, help needed - albertofenini - 01-18-2019, 01:48 PM

RE: HP25C repair, help needed - teenix - 01-19-2019, 03:39 AM

RE: HP25C repair, help needed - albertofenini - 01-19-2019, 10:04 AM

RE: HP25C repair, help needed - AndiGer - 01-19-2019, 06:09 PM

RE: HP25C repair, help needed - albertofenini - 01-19-2019, 07:58 PM

RE: HP25C repair, help needed - albertofenini - 01-19-2019, 08:43 PM

RE: HP25C repair, help needed - albertofenini - 01-19-2019, 08:44 PM

RE: HP25C repair, help needed - mpark - 01-24-2019, 07:50 PM

RE: HP25C repair, help needed - AndyWalter - 01-20-2019, 05:00 PM

RE: HP25C repair, help needed - AndyWalter - 01-20-2019, 05:37 PM

RE: HP25C repair, help needed - AndyWalter - 01-20-2019, 05:40 PM

RE: HP25C repair, help needed - albertofenini - 01-21-2019, 10:32 AM

RE: HP25C repair, help needed - albertofenini - 01-26-2019, 10:23 AM

RE: HP25C repair, help needed - mpark - 01-27-2019, 07:28 AM

RE: HP25C repair, help needed - AndiGer - 01-26-2019, 04:02 PM

RE: HP25C repair, help needed - Geoff Quickfall - 01-26-2019, 06:14 PM

RE: HP25C repair, help needed - albertofenini - 01-28-2019, 09:01 PM

RE: HP25C repair, help needed - Geoff Quickfall - 01-28-2019, 11:35 PM

RE: HP25C repair, help needed - albertofenini - 01-28-2019, 11:57 PM

RE: HP25C repair, help needed - albertofenini - 01-30-2019, 01:30 PM

RE: HP25C repair, help needed - albertofenini - 02-16-2019, 10:35 PM

RE: HP25C repair, help needed - burkhard - 02-18-2019, 07:04 PM

RE: HP25C repair, help needed - albertofenini - 02-19-2019, 01:48 PM

RE: HP25C repair, help needed - ijabbott - 02-19-2019, 04:59 PM

RE: HP25C repair, help needed - burkhard - 02-19-2019, 05:09 PM

RE: HP25C repair, help needed - albertofenini - 03-03-2019, 11:38 PM

User(s) browsing this thread: 1 Guest(s)