The TS-530/830 mod and upgrade thread

[KA2PTE]

As per AG6K's page on somis.org :

Rapid jumps in VFO frequency. Cause(s): [1] This can be caused by fluctuation in the 9V regulated power-supply voltage, which is the result of an intermittent connection between the AF-AVR [automatic voltage-regulator] Unit's circuit-common and chassis ground. Fix(s): [1] Solder a wire to the "TPG" terminal, next to C81, on the AF-AVR Unit. On the other end of this wire, solder a #6 ground-lug with locking teeth. The ground-lug is placed under one of the nearby sheet-metal-screws that fastens the AF-AVR Unit to the chassis.

An alternate method, if you are already doing other work on the board is to merely scrape off the coating at (2) locations
on the foil side and make solder jumpers. This will effectively bring the floating ground condition permanently to a
hard wired ground coming in on the +40V line for the power transistors. That way if over time the screw loosens, its irrelevant. This photo shows the procedure, works on both AVR boards in either radio.

HPIM0814.jpg

[KA2PTE]

The OMRON branded relay on the 530s's IF pcb, the same kind used on the 830's AVR board is a well documented point of failure in both radios mostly for rx issues. There is a solution for the obsolete relay out there on K4EAA's site, however I chose to carefully and painstakingly clean my relay contacts in both radios with a nail file and compressed air. It took 2 attempts but I got the relays working again and so far for many months, there's no issues. Of course I dont do much CW, but I imagine during CW operation, these relays take a pounding and that could be why they are prone to faults.

Also, its well known that the coils on any relay will produce a high voltage counter_emf every time voltage is removed. Snubber diodes are usually placed on the coils to absorb the voltage so its not applied to the circuit design. However over time snubber diodes will get tired and develop hard to spot breakdowns of the junction reverse bias which could cause the relays open and close time to be effected. While I was working on my AVR board, I decided to change D10, the snubber as a maintenance item. I upgraded it to a new motorola 1N4003 series diode I had in my parts bin. While the original 1S1555 diode is lower current and faster switching, the 4000 series diode will take more abuse, so I tend to like this approach. The only drawback may be the 4000 series is rated at a slower reverse switch time then what its replacing, but I dont think its great enough than the actual open and close time for the contact, unless someone hooks up a cw bug and tries 100wpm code.

I took photos showing D10 on the 530S's AVR board, before and after the swap.

Before HPIM0815.JPG After HPIM0816.JPG

On the 830S, the Diode is D27 and is right next to the OMRON relay in plain view. Apparently they moved the relay from the IF board to the AVR board in the 830S.

HPIM0817.JPG

In the past I have seen relays in other gear fail due to the snubber actually reading like a resistor after many cycles. This could be because the diode itself was cheaply or poorly made or the counter EMF somehow exceeded the diodes rating.