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Digistop 710 stop-watch timer

This stop-watch timer sports 6 Hitachi CD61 nixie tubes. It dates from around 1970. Judging by the brand (“Luctor” from Baarn used to be a brand of school supplies) it must have been intended for school use, e.g. timing of experiments of some kind in a physics class.

There are two buttons at the front: one to reset the counter and a start/stop button. The connections to both buttons are avalailable on a 3-pin DIN connector at the back, probably intended to connect the timer to external switches connected to the experiment to be timed.

Inside view

Inside view. You can see the circuit board and the 6 nixies, with the hitachi logo and type number clearly visible.

The technology is TTL, using a basic design. Inside are 6 SN7490 decimal counters and SN74141 decoder/nixie driver IC's. On the circuit board there is space for another 2 decimal counters, so it is possible to change this device into a nixie clock. There would be one disadvantage to this: because of the TTL technology used, the power consumption is relatively high (about 15 W). And I am not sure the power transformer is designed for continuous use. What is worse, is that the power supply is not stabilised. The designer must have been a truly optimistic person.

Copyright © 2002 by Onno's E-page         published 2002-04-01