I don't work for Astron but hate to see them get a bum rap because of a few failures.
If you are willing to listen, let me point out details you have never considered or wanted to know. Let's start with why no ASTRON is UL listed. It has exposed live electrical components and unprotected metering wiring. All those exposed pass transistors have unregulated DC voltage, 19 to 23 volts depending on load. The collectors of the transistors are exposed and connected directly to the output rectifier/capacitor bank. Something comes in contact with the aluminum heatsink and collector, and BANG, dead short to chassis ground.
The panel meters have unfused and output voltage on them. Astron connected the panel wiring directly to the output without any current limiting device like a 2-cent 100-ohm resistor. They place calibration pots on the back of the meters rather than on the circuit board to protect the meter wiring—no UL cigar for Astron.
Grounding is a severe issue posing both safety and operational problems. Aside from the QC issue I pointed out earlier with the AC equipment ground chassis termination, the bonding of the chassis to the negative DC output is dangerous, destructive, creates RFI, and corrupts all and any grounding and bonding efforts. No other DC power supply manufacturer would do that because they know it does not comply with electrical codes and practices. All electrical codes and practices require all electrical systems to be Isolated from each other in the event of an electrical fault. If there is a fault (short circuit or high voltage), the fault current flows in all interconnected systems and can cause extensive damage to both systems. It is not rocket science, simple parallel circuit laws.
Hams compound the problem when they fail to comply with electrical codes. Hams intentionally place themselves in a ground loop, and your Astron makes it a DC ground loop. You run the coax directly outside to an earth ground (ground rod) rather than the AC Service ground before entering the house. Here is what hams do; ground rod outside the shack to bond coax shield > coax shield inside to radio chassis > radio chassis to DC negative > DC negative to Astron chassis > Aston chassis to AC green wire in the power plug, power plug ground to AC earth ground aka service ground. You just placed yourself between two earth grounds with a serial daisy chain. You do not have a ground; your radio equipment is used as wire to connect two ground rods.
As a result, you get lots of problems you cannot fix or use tons of toroids trying to fix. With the DC negative bonded to the chassis, you lost your electrical and galvanic isolation between AC and Dc power systems, completely defeating the purpose of the transformer. All the noise currents in your home AC equipment ground system flow in your DC ground system and vice versa. You get a second DC negative wire. The one you know about, and the other is out on your coax shield to the ground and loops back around to the AC Service ground. You will have DC flowing on your earth ground system. What happens when you force DC current on ground conductors in moist dirt? Can you say galvanic corrosion destroying your ground system? Comply with codes and get rid of the jumper inside the Astron, and all that goes away.
Now let's talk about circuit design or the lack of it. I already addressed the voltage pot; however, another little tweak goes with it. If you cut the circuit trace to pin 4, the Inverting input and insert a 1K-ohm 1/8-watt resistor enables the Astron to be used as a Float charger, meaning you can connect a battery directly to the output with a fuse. No expensive high current blocking diode is needed.
The reference voltage amplifier has absolutely no filtering or soft start-start circuitry. A simple RC filter of a 3.9K ohm resistor and 10 uf cap placed between pins 5 and 6 give you an excellent soft start circuit and filtered voltage reference.
The LM723 power input is not regulated, resulting in poor PSRR. The LM723 has two power inputs: the regulator and the driver circuit. The driver circuit does not require a regulated voltage, but the regulator does if you want a power supply with decent PSRR. A proper design used a 78xx to supply power to pin 12 V+.
Current limiting and sensing are poor at best. Astron senses current via one of the pass transistor ballast resistors rather than a sense resistor on the output measuring the actual current. Inaccurate at best. Due to cutting corners and not using a series current sense resistor, Astron uses a resistor/diode network to simulate a current sense resistor to limit and control current, resulting in sloppy, inaccurate control. Compounding the issue is the 723 itself. If one looks at the Junction Temp vs. Current Limit, one instantly knows the 723 current limiter accuracy is poor.
RFI filtering, what RFI filtering? Astros lose regulation when used in solid VHF and UF environments like a collocated repeater site. Astron tried to address the problem 20 years ago by hanging an electrolytic cap across the output terminals. Any circuit designer or engineer with common sense knows that is useless because the ESR and inductance of the wire lead on the capacitor completely defeat the purpose.
The ICAS ratings are fiction. If you run the thermal analysis on the heatsinks clearly shows the rating is pure fiction. They get away with it because they know most hams do not push the limits. However, battery users, like repeater users, understand better. The first time your site goes on battery or places a discharged battery on an Astron without seriously reducing the current limit o 50% of the rating, it will require replacing the past elements. About the only thing most can do is run the output voltage as high as possible to minimize the thermal stress around 14.2 to 14.4 volts. Alternatively, if you know what you are doing is, add a 6/12 Vac buck transformer on the input to knock the transformer output voltage a couple of volts.
The bottom line is that the LM723 is an outdated late 1960s technology with high-side voltage control. It is inefficient, and when compounded by Astrons' poor design and QC, it is a poor choice when there are modern designs for less money carrying a warranty, UL, and FCC compliance.
For more reading, there is a website with a dedicated section on all the problems, fixes, tips, and tricks, along with every Astron schematic at Repeater Builder.