Archive for the ‘Retro Clock’ Category

VFD Clock

Monday, May 25th, 2020

Tiny IV-21 VFD Clock

Preview(opens in a new tab)

Hello, I have build this beautifull clock some time ago, the author have share all necessary stuff to buil it in hackaday.io website. I have encontered some problems that I have solved and I hope to help someone else:

All neccessary files taken from the above link can download from here

PCB

The JLCPCB PCB manufacter have reported to me a problem in traces space distance that is too small, so I have modified the gerber inaccording the of JLCPCB rules, in addition I have substitute the power connector.

Components

Parts List

  • C1 0.1uF
  • C2 22pF
  • C3 22pF
  • C4 0.1uF
  • C5 33uF
  • C6 100uF
  • C7 0.1uF
  • C8 0.1uF
  • D1 1N5817-B
  • DBG TSW-104-07-G-S
  • H MOMENTARY-SWITCH-SPST-PTH-RIGHT-ANGLE
  • J1 ICSP
  • J3 DC_POWER_JACK-PJ-102AH
  • L Red
  • L1 2mH
  • M MOMENTARY-SWITCH-SPST-PTH-RIGHT-ANGLE
  • N LSP11
  • P LSP11
  • Q1 32.768kHz
  • R1 10K
  • R2 10K
  • R3 1K
  • R5 10K
  • RFIL
  • SP1 SPEAKER/AL60P
  • SV1
  • T1 3904
  • T2 2N3904
  • U1 MAX6921
  • U1 DS1302S+
  • U2 ATMEGA328P_TQFP
  • X1 TSW-102-07-G-S
  • Y1 16MHz

Because of I haven’t all neccessary component in SMD package, I have adapted some throught hole component to the PCB (see the pictutes above for detail) .

About DS1302S+, I have used a separate module that I have connected to PCB using wires.

IV21 pinout identification

A big problem that I have encoutered was pins identification of IV21 VFD valve. In the hackaday.io project post no mention how to do that. From here is a post where is described the pinout or you can download pdf datasheet in cyrillic 😉

But the problem was where is located pin 1? The pins apparently have the same distance between each others! Pins 1 and 10 are connected to cathod filament, so just use a continuity tester and when you find no resistance between 2 pins, you have found pins 1 and 10. After locating pin 1 you have to count clockwisw to locate pin 2,1…19.