TS

TS-520/S/SE (using DFD2-520 recommended for the TS-520S and SE)

usable on the TS-520 by tapping signals inside radio using emitter follower shown below.

the AADE preamplifier kit may substitute for the emitter follower.

Installation consists of connecting three inputs via triple audio/video cable.

Power is taken from Counter power connector. You only need to connect to the + side. Ground is provided by the coax.

I cannot find a connector to fit that jack so I used a single pin removed from an old octal tube socket wrapped in tape or heat shrink. I think a Molex female pin could also be used.

One customer made a connector by cutting down a PC power supply molex connector and shaving it to fit.

Other end of triple cable is connected to the jacks intended for the DG-5 display.

The HF output of some 520S/SEs may not have enough output on the 10 meter band.
IF so
Try shorting the 1K series resistor on the DFD HFO input.
OR add an AADE preamplifier kit to the HF input

Here are some usefull comments from a customer.

Hi Neil!
Just wanted to mention that my C-520 frequency display - two line, blue - arrived July 27/06. I hooked it up, but only the blue display light came on. I opened it up - and in shipping one of the boards that plugs into the other board had become detached. I plugged it back in and it worked. I wanted to mention this for your future reference in case others have a similar problem - it is a very easy fix.
(I usually put a rubber band to hold the boards togather but must have forgotten)
Initially there was a problem with the digits bouncing around - but this was resolved simply by grounding my TS-520SE as it should be. Now the display is very stable. Again, if others were to have a similar problem, this would be a good starting place for them to check - make sure your transceiver is grounded as it should be.
I found using a small alligator clip with a rubber boot worked great for tapping off the power for the C-520 from the TS-520SE power socket.
I am very impressed by the C-520 display - very nicely constructed inside and out and works very, very well.
Many thanks for an excellent product!
Phil

The TS-520 (not the TS-520S) requires an emitter follower to buffer the HFO

An adapter was available to allow the DG-5 to be used with the TS-520, called the DK-520.
It's schematic is shown here:
- click to enlarge
All your really need is the emitter follower shown below with a little circuit board for it (you could use dead-bug construction or vector board construction easily).
You don't need the little resistor / capacitor combinations for the carrier and VFO inputs as these can go directly to the C-520 digital dial.
The VFO input connects to pin 1 or the remote VFO connector and gnd to pin 2.
The Carrier input connects to the OUT terminal of carrier unit X50-0009-01.

PRINTED CIRCUIT BOARD

Thanks to WA4PJP for supplying this information.

TS-520 (using DFD3 recommended for the plain TS-520 (no S or SE))

The TS-520 has a 9 pin plug on the rear panel for an external VFO.
The VFO connection on the pcb of the DFD3 goes to pin 1.
The VFO ground goes to pin 2.
The negative (-) PWR connection goes to pin 3.
The positive (+) PWR connection goes to the jumper that connects pins 8 and
9 together. It's 9 VDC which powers the DFD3 just fine. Do NOT remove this
jumper.
It works really good, no need for a battery or switch, it comes on and goes off when the rig does.

73, Bernie KF4FHS