> "wb6fly" <wb6...@...> wrote: > I should point out that Astron has made several significant > changes to the RS-series regulator boards over the past 20 years,
Amen... notice how I've been steering clear of this thread? There are/were so many board revisions and design shortfalls that I just didn't want to patch their circuit, which is the reason I choose to start making my own. > For what it's worth, almost every Astron regulator board I've > seen has a few extra resistors or capacitors added to it, as > if each one was "customized" during manufacture. Yep, parts were added to make the main board work for different models. As one example the crowbar circuit on some models is right on the regulator board, others external and case mounted. I have a parts table for the various Astron Regulator boards so if you smoke a resistor (or any other part) I can probably tell you the original value. > According to Fred, Astron's lead technician, some components > are still being changed to make the units more stable- decades > after the original design! They still appear to have not closely read and applied the LM-723 chip engineering data sheet. My original replacement regulator board is still pretty much the same circuit although the next generation pc board will appear slightly different. Since there are so many regulator board part versions based on the model and type of supply... it's hard to single out a specific problem unless I/we know your a bit of the internal details about your supply. The original problematic regulator circuit suffers from susceptibility to RF, less than optimal engineering in the SCR detect and trigger/ fire circuit, sometimes not so great parts placement and soldering. It's sometimes hard to know what power supply regulator board version and chassis layout you really have without lifting the lid to have a look. cheers, skipp skipp025 at yahoo.com
