24-08-2022, 11:31 AM
Old bench PSU's are tricky to find manual's and schematics for, I have a KSM SCT 500 3 500v 3A bench PSU with no info on it at all but managed to fix it when it developed a fault. It's very complex, yours though is hopefully simpler, it should be pretty straight forward David, a DC supply from the tfmr and smoothing caps into the the 807's probably connected in parallel as the series pass element, the gas valve as the voltage reference and the two EF91's as error amp and 807 "driver.
Is it working ok or does it have a fault? You could try giving Telford a ring, their site shows a few APT manual's - http://www.telford-electronics.co.uk/manual.php?alpha=a but not yours. Studying a few similar bench PSU's might help you draw out a schematic, see - http://www.pmillett.com/HV_bench_supply.htm & http://diyaudioprojects.com/mirror/membe.../reg1.html for more info.
Andy.
Is it working ok or does it have a fault? You could try giving Telford a ring, their site shows a few APT manual's - http://www.telford-electronics.co.uk/manual.php?alpha=a but not yours. Studying a few similar bench PSU's might help you draw out a schematic, see - http://www.pmillett.com/HV_bench_supply.htm & http://diyaudioprojects.com/mirror/membe.../reg1.html for more info.
Andy.
