Duplicat's Diary

Electronics fun
by Rick at 23:24:28, 2019-05-21 (day 1843)

One of the things that started playing up on our way over was the controls for the lights. In particular, I suddenly noticed that we had no nav lights on, whilst bouncing around in 30knots going upwind, approaching the pass. Not ideal!

Duplicat was built before CanBUS-style control systems, and so they came up with a nice solution - rather than running all the switch gear and power cables up to the nav table, they used ribbon cables and some separate control gear. Switches and tell tail LEDs at the nav table (which show both functioning and power failure due to fuse etc) and relays with fuses down in boxes in the hulls on (usually, but not always) the appropriate side.

I’m familiar with these as I’ve played with them to add new services a few times. Its all bespoke and the company who made them has gone out of business, however it is all discrete logic (4xxx series for those really old school hackers following along).

So today, I am re-acquainting myself with 4013 D-type flip flops, oscilloscopes and the like. The sucker punch is that the one working card has the flipflops soldered on, whereas on the failed cards they are socketed (yay!). So I can’t trivially swap the flip flop chips around. And this being New Caledonia, people look at me as if I’m unhinged when I ask for a proper electronics shop that sells CMOS chips. To be fair, its an order item in the UK which is of course, the next stop - Amanda can bring me replacements when she comes out.

Until then, we need a plan. It may be that we use the one working board and swap cables when we need to turn services on/off (which is usually at the start and end of a trip, and dawn/dusk (as we change the light setup).

These cards are a known issue on Privileges due to the lack of spares. Some enterprising folks have actually drawn up their own boards and had some made. I tried to order some but it didn’t happen (I was cruising so I think I missed out on an announcement). But discrete logic should be fixable and certainly would be if I was in the UK with spares on hand and friends nearby who could help me puzzle it out.

Another day in paradise... :)