Thursday, 29 January 2015

TKB Build - 4 - main PCB - Semi-conductors

*** Click here for the TKB Build Index ***
The diodes (6x 1n4148) are already in. Transistors & integrated circuits to go.
The main board uses 10 transistors:
One PN4250 & nine PN5179. (my vintage TKB uses nine EN5179s)

 This is a pic of a vintage EN5179.

Today the PN5179 and EN5179 are very hard to get, so they have been replaced with the more common 2n3904.

The PN4250 is unchanged from the original.

There are 9 types of ICs used on the main board.
These are:

1. LM324N. We need 4 of these.
     Mouser #: 512-LM324N    
     Manufacturer: Fairchild Semiconductor
     This is a quad Operational Amplifier.

2. 4042. We need just one of these
     Mouser #: 595-CD4042BE   
     Mfr. #: CD4042BE
     Manufacturer: Texas Instruments
    This is a CMOS quad clocked D-type latch.
For more about latch circuits click here:

 3. 4050. We need 3 of these
      Mouser #:     595-CD4050BE    
      Mfr. #:     CD4050BE
      Manufacturer:     Texas Instruments
     This is a non-inverting hex buffer.
Some info on buffers:

 4   4051. We need 3 of these.
      Mouser #:     595-CD4051BE     
      Mfr. #:     CD4051BE
      Manufacturer:     Texas Instrumen
      The CD4051B is a single 8-Channel multiplexer having three
       binary control inputs, A, B, and C, and an inhibit input. The
       three binary signals select 1 of 8 channels to be turned on,
      and connect one of the 8 inputs to the output

5. 4069 - We need two of these.
      Mouser #:     595-CD4069UBE    
      Mfr. #:     CD4069UBE
      Manufacturer:     Texas Instruments
      The 4069 contains 6 CMOS inverter circuits.

     For more info click here:LOGIC INVERTERS

6. 4081 - We need two of these.
     Mouser #:     595-CD4081BE     
     Mfr. #:     CD4081BE
     Manufacturer:     Texas Instruments
     This is a Quad 2-Input. AND Gate.

For more info on Gates click here: LOGIC Gates
7. 4516 - just one is needed.
    Mouser #:     595-CD4516BE    
    Mfr. #:     CD4516BE
    Manufacturer:     Texas Instruments
    Desc.:     Counter ICs Binary Up/Down

8. 4520 - We need just one.
    Mouser #:     595-CD4520BE   
    Mfr. #:     CD4520BE
    Manufacturer:     Texas Instruments
    Desc.:     Counter ICs Dual Binary Up

9.  MM74C150
     This is a 16 line to 1 line Multiplexer
      Datasheet info

Part 5. Pot boards.
*** Click here for the TKB Build Index ***


  1. Very informative! Thanks for such a clear guide packed full of supporting information!

    1. My pleasure Jason.
      Let me know how you go. If you pick any mistakes or think of any info I've omitted do let me know. Best of luck with your build. Jono