previous <<==>> next

POST  /  SIEMENS & HALSKE
PORTABLE  DC / AC  VOLT / AMPERE  METER


Dimensions ( W x H x D )  15 cm x 19 cm x 10 cm  /  6" x 7_1/2" x 4"

Portable  DC/AC  V/A-Meter  POST / SIEMENS & HALSKE   Germany (1930)
********************************************************************
Class 0.5         3 V .. 300 V DC/AC        450 mV = 450 μA  x  1 kΩ

This  beautiful instrument  came  "as-is"  without its shunts.  Now,
because the  ONLY AMPERE-RANGE  is 450 μA,  a  SHUNT  was home-made:
Experiments  with  HELIPOTS   &  WHEATSTONE BRIDGE  resulted  in  a
3 Ω  RESISTOR  to have a  150 mA (DC/AC) RANGE  available ...

               

R E M A R K S   T O   R E S T O R A T I O N :
====================================================================
AC  was not working,  because  the  "KUPFEROXYDUL-MESSGLEICHRICHTER" 
G1441/1  (= Bridge-Rectifier )  was defect.   ...  Disassembling ...

   
                Back Side  Front Side       A
                                            |
   

... showed:  Dead rectifier pearls !  EXPERIMENTS  with different
Diode types ( Germanium-, Selen-, Silizium-, Tunnel-, ... ) until
found the SOLUTION: 4 * BAT-43 SCHOTTKY BARRIER DIODES to replace
the dead pearls - MATCHING THE EXISTING  S C A L E  CALIBRATION !

The G1441/1 DIAGRAM and a snapshot of the REPAIR PROCEDURE ...

              
impressum:
********************************************************************
© C.HAMANN    http://public.beuth-hochschule.de/~hamann     04/27/09