Hello. i need an advice regarding a power supply i'm trying out.
it is from Elliot sound products ESP : https://sound-au.com/project05-mini.htm
i didn't want to zombify this thread even if is related (same circuit) to this one.
https://forum.allaboutcircuits.com/...gulated-15-15v-circuit-question.131169/page-3
So..
as adviced in the ESP page, i connected Ground and AC2 to my 15VAC trasformer. (full-wave voltage-doubler type)
it works, i get the result as shown if the picture BUT mystery arrives now:
from time to time (more or less once every 4/5 time that i switch it on.. kind of randomly), the regulated +15V doesn't work (measuring from pin 3 of the 7815). it remains 0v.
why such a thing happens? and why just sometimes?
i also attach a picture of what happens when i switch off the circuit (in case of the above mentioned malfunction):
the unregulated - 20V and the regulated -15V slowly decrease towards ground as expected,
the positive at 0v and the unregulated +20V stay still untill the negative rails go down to around -2v and then instantly the ''regulated'' drops at +15V for one second and then both descend towards 0v .
i hope the last part is clear and thanks in advance if someone can help me out.
EDIT: this will be more explanatory than words:
it is from Elliot sound products ESP : https://sound-au.com/project05-mini.htm
i didn't want to zombify this thread even if is related (same circuit) to this one.
https://forum.allaboutcircuits.com/...gulated-15-15v-circuit-question.131169/page-3
So..
as adviced in the ESP page, i connected Ground and AC2 to my 15VAC trasformer. (full-wave voltage-doubler type)
it works, i get the result as shown if the picture BUT mystery arrives now:
from time to time (more or less once every 4/5 time that i switch it on.. kind of randomly), the regulated +15V doesn't work (measuring from pin 3 of the 7815). it remains 0v.
why such a thing happens? and why just sometimes?
i also attach a picture of what happens when i switch off the circuit (in case of the above mentioned malfunction):
the unregulated - 20V and the regulated -15V slowly decrease towards ground as expected,
the positive at 0v and the unregulated +20V stay still untill the negative rails go down to around -2v and then instantly the ''regulated'' drops at +15V for one second and then both descend towards 0v .
i hope the last part is clear and thanks in advance if someone can help me out.
EDIT: this will be more explanatory than words:
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