June 2020 Quiz

Just for fun, each month, we post a short quiz challenging your knowledge of the club or amateur-radio in general. It might be a piece of WIARC history, or a technical question, perhaps something borrowed from the current qualification exam question bank. We will also post the answer to the previous month’s quiz and the names/callsigns of anyone who submitted a correct answer to webmaster@wiarc.ca, or just use the website contact form.

June 2020 Quiz:

You may have noticed a photo of this circuit in the photo gallery captioned “A piece of WIARC History”. This month’s quiz is to guess what it is, approximately when was it built, what it did, and any other information that you may devine. I suspect not very many current members know the answer, so we will also accept humorous wrong answers (specify “wrong answer”) and we will publish any funny wrong answers. Of course if you think you know the actual right answer, go for it!

This is a home-brew circuit (both in design and construction) by WIARC members at the time, as part of a larger club project. Here is a close-up shot of the component side of the board and a list of all active components on the board:

Mystery circuit

Active Component List:

Qty                 Part Number         Description
1                      MM2716                 16 kbit UV Erasable PROM
4                     74LS00                   Quad 2-Input NAND Gate
1                      74LS76                   Dual JK Flip-Flop
1                      74LS77                   4-Bit D Latch
2                     7493                        4-Bit Binary Ripple Counter
3                     LM555                    Timer IC
4                     2N3904                  General Purpose NPN Silicon Transistor
1                     1N4001                   General Purpose Silicon Rectifier Diode
3                    1N914 ?                    Small Signal Switching Diodes

In addition to the above active components, there are many resistors and capacitors, 2 variable resistors and two momentary push-button switches and one LED mounted on the front panel of the device. The circuit is coated in a generous layer of dust. The circuit appears to be designed to plug into a card-cage chassis through a 22-pin connector on the back of the board. Construction is a combination of wire-wrap for IC sockets and point-to-point soldering between feed-though discrete components. 

Good Luck! If you wish, you can submit your answer (best real guess or humorous wrong answer) to webmaster@wiarc.ca. The answer will be published at the beginning of July, together with a new monthly quiz for July.

Correct answers to date:

  1. Rick VE7RY
  2. Jan VE2JL

Funny wrong answers to date:

  1. Mark VA2MM:
    Automatic license examiner. Press the button on the front. If the LED lights up, you pass. If not, too bad.
  2. Wayne VE2WRH
    Breathalyzer, mounted inside driver’s door. If alcohol level is too high when starting engine, car explodes.