Identifying 82120a components



I'm taking the 82120A wave and I'm repairing the rectifier/regulator board of mine, serial # 2309S80xxx. Battery leakage corroded part of some components terminals and, in some cases, the terminals are broken and I'll have to replace some of them. The problem is that the existing diodes had their ID's removed and I'm in trouble to identify them. One of our contributors offered himself to identify these components for me, and I believe this information is useful to all of us here. So, as I do not mention names in here prior to their authorization, if this friend agrees with, I'm expecting any information from someone at the Forum and I'll post any contribution sent to my e-mail about this particular subject, O.K.?

Dave, if there is any trouble regarding to copyright material, please, let us know. I'll expect e-mails only, in this case.

The general circuitry description for the 82120A is:

> from the AC input, four diodes connected as a bridge rectifier; the diodes connected to [+] pole are different of those connected to [-] pole. Is there any reason for that? Fast rectifiers will do the job? Which ones to use there?

> The first component after the [+] is an electrolytic capacitor, 100uF/25V, no trouble to identify

> Right after the capacitor there is a SOT-package regulator, 1826-0275 (output voltage?). The way it is connected lead to this conclusion: one terminal in the [+] pole, the mid terminal in the [-] pole, and the third terminal to the load through the following two components:

> A 10nF capacitor, parallel to load (opposite terminal to [-] pole)

> A series diode (anode to regulator, cathode to load), no identification too; is it a fast rectifier?

The other components are:

> Connected to the cathode of the last diode, a 365 ohms, 1% resistor (at least it seems to be), series with load; the opposed terminal goes to the [+] of the batteries

> parallel with the batteries a zener diode; working voltage? test current? max. dissipation power?

I'm sorry asking so many questions, but I prefer knowing these components' characteristics instead of risking and loosing the pack, the (external, test purposes only) NiCad batteries OR the calculator itself.

Thank you very much.


Possibly Related Threads...
Thread Author Replies Views Last Post
  Question for Valentin; Identifying Constants John Abbott (S. Africa) 16 2,106 05-23-2012, 04:24 AM
Last Post: Valentin Albillo
  Need help identifying a few components. Bruce Larrabee 2 592 01-31-2012, 07:39 PM
Last Post: Paul Berger (Canada)
  Identifying equations on HP 35s Richard S 4 770 08-10-2010, 08:01 PM
Last Post: Richard S
  HP41c rechargeable battery (82120A) circuit diagrams ? John Robinson 0 379 03-09-2010, 07:16 AM
Last Post: John Robinson
  DeSoldering SMD Components easily!!! - Chipquik Thomas Chrapkiewicz 1 450 11-01-2009, 01:14 AM
Last Post: DavidShenk
  Help Appreciated Identifying Unusual HP-41 ROMS Dan Grelinger 4 814 04-23-2008, 02:51 PM
Last Post: Dan Grelinger
  82120A battery pack Paul Beijer 4 725 01-20-2007, 12:32 PM
Last Post: David Smith
  The different of 2 kind 82120A battery pac Chiu Yiu Wai 1 423 05-03-2006, 08:52 AM
Last Post: Randy
  Identifying HP-71B modules Simon Williams 5 760 10-24-2005, 03:25 PM
Last Post: Frank Wales
  Identifying calc type in RPL valentino ducati 11 1,299 03-15-2005, 03:32 PM
Last Post: sjthomas

Forum Jump: