Phone Patch input connections - TS-530
Those who wish to run audio signals from a patch, data communications terminal or other device straight to the Mic Amp (instead of using the rig's Mic jack) will find this modification useful. The electrical implementation is fairly simple. The mechanical implementation is another matter entirely.
The best way to perform the mod is to de-solder J14 and fit an 8-pin header of the same (Taiko Denki TL-25) series. The TS-930S Signal Board is a good source for these. A circuit board mod consisting of drilling a small hole between two existing ones immediately to the left of J14 is required:
J14-Mods.jpg
Use a small Dremel ball mill to remove the ground foil in the area surrounding the new pin.
Next, modify the 8-pin header by removing the 4th pin from the left and installing it into the holes. You may have to use a solder removal tool to clean out the existing holes either side of the new one.
Note 1: The holes for J14 and the two others immediately to the left of it may not line up perfectly from one board to the next (I have several) but the 8-pin connector can be fit into place.
Note 2: There are a couple of ways to proceed when it comes to attaching a connector to the 'new' J14. One is to source an 8-pin plug and move the existing P14 wires to their respective positions, then add the new leads to the left side of the plug. The other (which is shown here) involves filing a slot in the back of the header barrier so the existing P14 (a 4-pin plug) and a new 3-pin plug can fit side by side. The new 3-pin plug takes a pair of T-D terminals attached to a length of Miniax...left is shield; middle is center conductor. I re-used a 6" length (complete with terminals) from a junked x30 wiring harness.
The modified 'J14':
New-J14-RL1.jpg
Also shown is a replacement relay for RL1; this available from K4EAA. I swapped it for the stock one in an effort to see if the S-meter "slam" condition would be affected. No dice, but no worse.
Make the Phone Patch input connection from 'J14' to the junction of C50, C51 and R61 with a 100K, 1/4w film resistor. The schematic attachment point:
Patch-Connections.jpg
And the underside of the IF Unit is shown here:
Phone-Patch-Resistors.jpg
Note the 10K, 1/4w film resistor which bypasses the input connector to ground. The patch connection is per Kenwood's TS-830S modification info, and the Mic Amp circuits are identical between radio series.
Check your work for solder bridges and replace the IF Unit in the radio. Rear panel connector installation is next.
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