Manufacturer: A/S BRDR. CARLSEN
Model: D51
AKA: CONTEX D51
Year: 1972
Display: LED-bar (16)
Circuits: ELECTRONIC ARRAYS
(see further on this page)
Dimensions: 215x205x68 mm
Power type: 220V
Origin: Denmark
S/N: 054000641
Owner: DEVIDTS Serge
Info:  


The machine has the same functionality as the D31,
plus four additional keys (on the left).
   

The D51 uses a LED-bar instead of a Monolithic Nixie-tune ^



The digit divider ^
This (non-electronic) switch can be placed in three different positions
so as to facilicate the reading of multi-digit results.
One of the pointers should always be placed under the decimal point.
If one is calculating without decimals,
the digit divider should be placed in its
left-hand posiution.


Internals: chips: ^
IC's from ELECTRONIC ARRAYS

1: 
2: 
3: 
4: 
5: 
6: 

  FDY: 150B-5005
 FDY: 110B-5001
 FDY: 320-7002
 FDY: 310B-7014
 FDY: 360B-7006-1
 FDY: 120B-5013



Internals: extra 4 small chips: ^

1: 
2: 
3: 
4: 

  TEXAS INSTRUMENTS: SN7490N (Decade Counter).
 TEXAS INSTRUMENTS: SN7402N (NOR Gate).
 TEXAS INSTRUMENTS: SN7404N (HEX Inverter).
 TEXAS INSTRUMENTS: SN7472N (J-K Flip Flop).

 

Power Supply ^

 

Keyboard construction ^

 

Case en dust cover ^

D11 / D31 / D51 instruction manual ^


Detail of the invoice ^
DM1.198 = app. $575

 

Task How to type Result
Setting decimals to 4 [C] [CE] 4 0.0000
1/(4+3) 4 [+] 3 [:] 1 [x/y] [=] 0.1428
72-((2+3)*4) 2 [+] 3 [x] 4 [=] [+>-] [+] 72 [=]  52

Calculating examples ^