ADMS Programming Cable PCB

After some time playing with the FT-50RD (brick!!) VHF/UHF handheld transceiver from Yaesu, I realized how useful would be programming it with the computer. I bought the ADMS-1E software, which came with a nice cable featuring the expected 4 conductor jack that drives everyone crazy. Everything worked OK, but the problem came when I lost the cable somewhere (I'm still looking for it...). I decided to make good use of some schematic I had found on the web. It should also work with the VX-1R, VX-5R and FT50R.

I find the use of the four conductor jack in the FT-50 a wrong manoeuvre from the guys at Yaesu. You cannot use standard headphones, standard Yaesu/Icom mikes and you will need to search for some time to get one of them if you want to put the brick on packet (why not?). I was lucky to have an old hearphone/controller cable from an old Aiwa walkman that had the same four connector jack at one end. I just savaged it.

The schematic has many more components than the PG4s interface cable for the Kenwood TM-V7, which you can find also in these pages. The reason is that the communnications to/from the Yaesu are bidirectional using a single wire. The TM-V7 has a wire for output and another for data input, dramatically simplifying the circuit, basically a TTL<->RS232 level converter. This time, using tiny SMD components would not be enough to come up with a PCB small enough to fit inside a DB-9 shell. It had to be SMD and double sided. That did make the thing much more complex. After some time placing components here and there, routing and re-routing tracks in AutoCAD, I finally got the following layout. You must be carefull when printing the PCB template, because depending on the transfer method you use, you may need to mirror the image. This is how you should see the traces if you could look thru the board while looking from the other side:

This is what the PCBs should look like as viewed from the top:

Making the doubled sided PCB is not a major problem. If you follow this instructions, you will get a double sided PCB that no one will be able to tell wether it was double sided from the start or not:

  1. Use fiberglass PCB, no other type will work.

  2. Transfer and etch the two different boards found in the picture using two different pieces of PCB.

  3. Drill the holes for the cross connections on both boards (.75mm diameter aprox.).

  4. With a sharp knife (not a cutter which will be too thin and won't help) peel of as many fiberglas layers on each board as neccessary to make it half the width it was originally. Do this one layer after another, starting from the corners.

  5. Put together the two boards, with the copper tracks on the outside. Verify that the five through holes line up on both sides of the other board. If they are not exactly centered but you can see a little thru them, don't worry. Drilling after the boards have been glued will solve the problem. If they are not close enough to see light thru them, you'll have problems connecting the track on one side with the one on the other, but go on if you think you can make it. Trim the borders of both boards until they get the same shape and size.

  6. Glue the two boards with a drop of SuperGlue (epoxy would be better, but you'll have to wait) Try to put together the boards with the hole in place at the first attemp, I don't think you'll have another. This is why trimming the borders appears on the previous point, to help you get the correct position of one board over the other accurately.

  7. Insert a thin wire on each hole and solder to both sides.

That's all needed to get this lovely board:

Thanks to my friend Angelito "de Cuenca", EB4EKJ for the digital picture.

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