[TenTec] Astron SS30 power supply leave on?

[Mike Bryce]

The Astron power supplies use the 723 linear voltage regulator IC. It’s very durable, and there are millions of linear power supplies operating with that chip.

One of the problems with the Astron’s is they used the data sheet from TI about the 723, then removed every single part that they could yet still have the circuit operate. It’s under designed.

And like Stuart said, the first thing to go in the regulator IC, especially during electrical storms with the supply plugged in and turned on.

Another ‘under design’ in the Astron supplies is the continued habit of the designer to use one of the emitter balancing resistors as the shunt for the current meter. The resistor needs to be there, so, they use it for a dual purpose. Because of this design, the current meter is far from accurate.

Instead of using a full wave bridge, they use, as Stuart said, only two diodes in a bridge block. It must be cheaper that way instead of using two stud mount diodes.

They also have a tendency to use two bridge rectifiers in parallel in their high current supplies.

But with all the lumps and bumps, they are rather robust, many of them operate for decades without fail. 

yet, with that being said, I’d think hard about putting on in repeater service when it takes a 4X4 two hours to climb to the hill top to the repeater site.

Google ‘repeater builder’ and you’ll find tons of information on making these supplies more robust, more reliable, and safer.

I have a Astron SS-30 that had been on for 18 years none stop. It failed last spring,  the PWM chip when out. Replaced the chip and all the high zoot capacitors and I expect another 18+ years from it.

I do leave my power supply on all the time. No matter how much it storms and how many lightening strikes are taking place. It’s built to take it— 36 6-volt 220 amp/hr batteries run the shack


Mike Bryce WB8VGE
prosolar at sssnet.com