The TS-530/830 mod and upgrade thread

[N8YX]

TS-530 Screen Grid switch, AF Unit modifications

The rear panel Screen Grid switch must be rewired to switch a +12VDC signal to the Rectifier Unit, following the TS-830's circuit. Easiest way to do this is to unscrew the unit from the chassis then trace each lead (two to the Rectifier Unit; one to the PA Unit PCB) and remove them from their attachment points. Next, de-solder the wires from the switch and set it aside.

Other than form factor and ancillary circuits, there's very little difference between the Audio Units of the TS-530 and TS-830 series. Examining the ALC portion of the assembly, the sole missing connection is the "XAL" (Transverter ALC) line. This is easily fixed. First, remove the AF Unit and locate J10 - a 2 pin TL25-series header. De-solder it and source a 3-pin version, then use a dental burr in a pin vise to drill a hole for the 3rd pin. Following Kenwood's connector positioning practice, install the header and solder two pins in place at the existing foil pads.

XAL-Connector-2.jpg

Next, source a VO6B (1A; 600PRV) diode or 1N4000-series equivalent. An existing, non-drilled solder pad (indicated by the orange arrow in the picture below) was evidently meant to accommodate the needed diode but somewhere along the line the parts (along with the artwork for the connection to the header) weren't included. Trim the leads short and install as shown; cathode to the empty header pin:

XAL-Connector-1.jpg

Lastly, source a 3-pin TL25-series plug and a suitable wire with installed crimp terminal. I followed Kenwood's color scheme and used a white/green striped wire - the one from this connector position in the '830. Remove the connectors one at a time from the 2-pin plug and install them in the 3-pin unit, keeping their positions the same. Finally, insert the terminal with the "XAL" lead into the plug, plug the connector into the header and route the XAL lead along the rear part of the chassis to the area where the Xverter connector will be installed.

XAL-Connector-3.jpg

Install the AF Unit and connect any plugs which were removed.

ETA: See Tip #10 (post #39) for another AF Unit modification. I'd advise also doing this one while the board is out of the rig.