The following warnings occurred:
Warning [2] Undefined array key 47494 - Line: 275 - File: inc/plugins/threaded_mode.php PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php 275 errorHandler->error_callback
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined array key 47504 - Line: 275 - File: inc/plugins/threaded_mode.php PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php 275 errorHandler->error_callback
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined array key 47535 - Line: 275 - File: inc/plugins/threaded_mode.php PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php 275 errorHandler->error_callback
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined array key 47547 - Line: 275 - File: inc/plugins/threaded_mode.php PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php 275 errorHandler->error_callback
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined array key 47634 - Line: 275 - File: inc/plugins/threaded_mode.php PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php 275 errorHandler->error_callback
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined variable $thread - Line: 295 - File: inc/plugins/threaded_mode.php PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php 295 errorHandler->error_callback
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Trying to access array offset on value of type null - Line: 295 - File: inc/plugins/threaded_mode.php PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php 295 errorHandler->error_callback
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined variable $fid - Line: 295 - File: inc/plugins/threaded_mode.php PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php 295 errorHandler->error_callback
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined array key 47504 - Line: 331 - File: inc/plugins/threaded_mode.php PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php 331 errorHandler->error_callback
/inc/plugins/threaded_mode.php 332 ThreadedMode::buildtree
/inc/plugins/threaded_mode.php 304 ThreadedMode::buildtree
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined array key 47634 - Line: 331 - File: inc/plugins/threaded_mode.php PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php 331 errorHandler->error_callback
/inc/plugins/threaded_mode.php 332 ThreadedMode::buildtree
/inc/plugins/threaded_mode.php 332 ThreadedMode::buildtree
/inc/plugins/threaded_mode.php 332 ThreadedMode::buildtree
/inc/plugins/threaded_mode.php 304 ThreadedMode::buildtree
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined variable $theme - Line: 3 - File: inc/plugins/threaded_mode.php(305) : eval()'d code PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php(305) : eval()'d code 3 errorHandler->error_callback
/inc/plugins/threaded_mode.php 305 eval
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Trying to access array offset on value of type null - Line: 3 - File: inc/plugins/threaded_mode.php(305) : eval()'d code PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php(305) : eval()'d code 3 errorHandler->error_callback
/inc/plugins/threaded_mode.php 305 eval
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined variable $theme - Line: 3 - File: inc/plugins/threaded_mode.php(305) : eval()'d code PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php(305) : eval()'d code 3 errorHandler->error_callback
/inc/plugins/threaded_mode.php 305 eval
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Trying to access array offset on value of type null - Line: 3 - File: inc/plugins/threaded_mode.php(305) : eval()'d code PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php(305) : eval()'d code 3 errorHandler->error_callback
/inc/plugins/threaded_mode.php 305 eval
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Undefined variable $lang - Line: 5 - File: inc/plugins/threaded_mode.php(305) : eval()'d code PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php(305) : eval()'d code 5 errorHandler->error_callback
/inc/plugins/threaded_mode.php 305 eval
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks
Warning [2] Attempt to read property "messages_in_thread" on null - Line: 5 - File: inc/plugins/threaded_mode.php(305) : eval()'d code PHP 8.1.2-1ubuntu2.14 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/inc/plugins/threaded_mode.php(305) : eval()'d code 5 errorHandler->error_callback
/inc/plugins/threaded_mode.php 305 eval
/inc/plugins/threaded_mode.php 23 ThreadedMode::showthread_threaded
/inc/class_plugins.php 142 threaded_mode_showthread_threaded
/showthread.php 918 pluginSystem->run_hooks





Two different designs of the 82120A rechargeable battery pack



#2

I have two different battery packs for the HP-41 calculators, both are part number 82120A but they are very different. I have repaired the oldest one with serial number 2203S. With new 1/3AAA batteries it works just fine. I have taken some notes of the charging circuit and I see it is very similar to the classic series chargers. It has one circuit to charge the batteries and another one to keep the calculator working. The plug has three pins and one separated connector. When connected to the 9V transformer the connector doesn´t make contact with the third pin and both circuits work separately. When not plugged the third pin makes contact and the batteries feed the calculator.
The newest one has original cells and works fine. Serial number is 3112S. But it has two pins in the plug. It seems that it works like spices or Woodstock calculators, so it can be dangerous for the calculator if it is being charged and any cell fails. It seems that HP modified it to reduce costs.
Can anybody confirm my impression?. Does anybody know if charging times are the same for both designs?.


#3

Jon, good detective work. The 3-pin version is similar to the classics circuit. Perhaps after the failure lessons of the Woodstocks, they went back to what worked. But, I suspect the kapton film that acted as both an insulator and conductor had reliability, manufacturing or cost issues. So, out goes the safe circuit for a lower cost, easier to manufacture 2-pin unit.

But, unlike the Woodstocks, the 2-pin version 82120A has a 6.4 volt zener diode across the battery so that should be the maximum voltage the calculator will ever see. The only problem with the design is that there is no series current limiting device. When the batteries begin to fail and no longer present a low impedance to the source, the zener diode alone provides the load. Yes, it prevents the calculator from frying but leave it on charge long enough and the diode will fail due to overheating. Ask me how I know... At least they short when they fail and you have a dead battery pack but the calculator survives.

Charging times for both versions are the same.

Edited: 21 Nov 2003, 8:41 p.m.

#4

Actually, the three pin version is not as good or safe as the later version. It can glitch the power when the plug is mated. Also it can overvoltage the calculator if the cells open up or go bad... the later version has a protection zener (which I install in all the old versions when I rebuild them). Both units seem to pump about 12-15 ma into the cells.


#5

David, thank you, thats very good information. Have you ever had/heard of a situation where you end up with the dreaded MEMORY LOST message when plugging the charger in? I recently experienced this with a 3-pin pack and dismissed it to the pack having shifted and loosing connection with the calculator. Sounds like my assumption was incorrect?


#6

Sounds like the switch glitch hitch. Usually the cap in the machine will keep the machine running through the transient, but you know how glitchy glitches can be...


Possibly Related Threads…
Thread Author Replies Views Last Post
  HP 50g : More on best rechargeable batteries Miguel Toro 1 1,704 12-12-2013, 05:31 PM
Last Post: David Hayden
  HP 50g : Best rechargeable batteries ? Miguel Toro 14 4,602 11-16-2013, 03:35 PM
Last Post: Dieter
  HP 41 Battery Pack Rebuild John Ratard 0 2,081 09-29-2012, 01:37 PM
Last Post: John Ratard
  Rechargeable 2/3 AAAs in 41C-series Les Wright 7 2,538 06-14-2012, 12:43 PM
Last Post: Eric Smith
  Unknown battery pack Nick R 4 1,860 05-27-2012, 01:32 AM
Last Post: Nick R
  Disassemble Battery Pack 82028B (woodstock) Jacques Karensky 0 1,102 05-19-2012, 03:39 AM
Last Post: Jacques Karensky
  aOT--Battery/battery contact care advice needed Matt Agajanian 0 1,111 04-24-2012, 07:35 PM
Last Post: Matt Agajanian
  Replacing Rechargeable Batteries on TDS/SMI RAM cards aj04062 2 1,389 04-12-2012, 11:20 PM
Last Post: Geoff Quickfall
  HP41 battery pack Cristian Arezzini 1 1,302 11-07-2011, 06:36 AM
Last Post: Ignazio Cara (Italy)
  HP-19c battery pack replacement (again...) Xavier A. (Brazil) 8 2,628 09-22-2011, 04:41 PM
Last Post: Xavier A. (Brazil)

Forum Jump: