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Wednesday, 1 January 2014

The CAT is out of the bag


You may remember the old Yaesu FT-1000D I acquired a while back. It doesn't include a more modern CAT interface and has TTL level signals out of a 6 pin DIN plug and won't interface directly to a PC RS232 serial connector.

Since I had the radio I have been using a MicroKeyer to do the level conversion for me, but recently I got rid of the MicroKeyer to Vince, G0ORC as I wasn't really using it - he is far more CW than I!

I've tried to make a level converter for the radio today using a MAX232 chip, here's the schematic I've been following (stolen from the internet somewhere):

I built the circuit and have used two of the sockets on the back of the radio, one for the CAT signals and the other for the 13.6V feed that is available. Now, it just didn't work so I figured I may have got the inputs the wrong way round, or indeed the outputs.... but eventually I found that there was no voltage out of the FT-1000D external 13.6V power connector. So the lid (or in fact the base) came off the radio....

Now, I had forgotten how immaculate this radio was, it is also a pleasure to see no surface mount components!

Near the back of the box, just in front of the red connector on the LHS is a fuse for the 13.6V output - and yes that was the problem.

The next thing I did after replacing the fuse was apply the 13.6V directly to the MAX232 chip - it's a 5.5V maximum voltage component and got rather hot rather quickly... I've ordered another one!

Interesting though, egh?

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