04-03-2019, 08:54 AM
The replacement switch is already on order, plus I've found one(new) in my spares that would do. Haven't ordered the rectifier & fuses yet, so will check the Amps. Transformer first. I have a PSU from a scrap mini HiFi which would do for test purposes, although it's o/p isn't adjustable. As for the Blaupunkt ex-demo. stand PSU, all I can say is that I've used it for many years to power car stereos and amplifiers on my bench with no problems - it was, after all designed to power car stereos, has a hefty mains transformer and a regulated circuit using 2N3055s with an adjustable o/p (originally a pre-set which i replaced with a panel control ) The current limit isn't adjustable on either of my PSUs, but the 2Amp one does have s/c protection. I built the latter over 40 years ago from a design in PW. Again it uses a series pass circuit with a 2N3055 as the main pass transistor. I've used it to power may different items over those years, and have had to replace the 3055 maybe twice, but never needed to change any other parts, other than the odd blown fuse, in all that time. That circuit could probably be modified to become a dual rail one, though it would only be capable of a max. of about 13 - 0-13v without replacing the transformer.
