Repairing a 82022B charger (with P.S. to Geoff Quickfall)
#1

Dear all,

one of my 82022B chargers broke some days ago. A first investigation showed that the fuse was melted. But after replacing it, the same thing happened again immedeately. A further search for the root cause showed that transistor Q3 shortcircuited. It's a NPN power type with a "M726" printed on it. Alas I couldn't find any datasheet at the Internet. Does anyone know with which transistor available today I can replace it ?

Any hint will be very much appreciated - thank you very much in advance.

Kind regards

Karl

P.S.: By the way, Geoff, if you're reading this, may I ask how about your book ? Will it be ready for ordering soon ?

#2

Hello Karl,
take a look at this fantastic job of Jacques Laporte about the HP-35 and more old HP calculators:

http://www.jacques-laporte.org/HP35%20power%20unit.htm

Take care and regards.

Ignazio

#3

Hello Ignazio,

thanks a lot for your answer - I'll try my luck.

Best wishes and kind regards

Karl

#4

Dear All,

thanks again for the link Ignazio and thanks Jacques for the excellent technical content.

I succeded to repair the charger by replacing the defective Q3 with a BD128 which should be available at any electronic shop. A bit more difficult was to find a supplier for the fuse, a so called pico-fuse, which also was defect. For people living in Germany I found it at Reichelt Elektronik.

Best wishes and kind regards

Karl



Possibly Related Threads…
Thread Author Replies Views Last Post
  HP-67 charger Marcel Samek 3 1,707 11-22-2013, 10:45 PM
Last Post: Marcel Samek
  Repairing HP 65 Michae Altmann 5 1,992 03-15-2013, 04:13 AM
Last Post: Joel Setton (France)
  [41CL] Repairing an image in Flash Monte Dalrymple 0 875 01-24-2013, 07:01 PM
Last Post: Monte Dalrymple
  Book on repairing HP calculators? Dave F 24 5,762 11-23-2012, 06:46 AM
Last Post: Bart (UK)
  THE BOOK of Geoff Walter B 4 1,538 05-31-2012, 08:59 PM
Last Post: Joerg Woerner
  Thank you, Geoff Quickfall Geir Isene 8 2,328 05-06-2012, 11:32 PM
Last Post: Matt Agajanian
  HP-67 wall charger Wytnucls 2 1,309 04-19-2012, 10:13 PM
Last Post: Dan W
  HP 97 charger Harald 2 1,244 03-30-2012, 02:01 PM
Last Post: Harald
  Which charger for a35 Matt Agajanian 3 1,486 03-23-2012, 02:58 AM
Last Post: Marcus von Cube, Germany
  Aristo M85 -- What charger? Gene Wright 9 2,819 11-03-2011, 04:56 PM
Last Post: Mike (Austria)

Forum Jump: