Explain purpose of this diode
Explain purpose of this diode
(OP)
Refer to astron linier PSU schematic:-
http: //www.repe ater-build er.com/ast ron/pdf/as tron-rs50a -rs50m-rm5 0a-rm50m-1 996-03.pdf
I aquired this broken 723 based PSU with blown components:-
CR1+2 35Amp diodes, 723 reg, q2, 3771 driver and diode CR5. I can easily repair, but cannot understand purpose of CR5. It apears to make circuit self destructive. If crowbar trips, output collapses. This causes 723 to drive high current thru be junction of Q2, CR5 and 2n3771. Current is NOT limited, as CR5 does not allow R1 (which is in parrallel) to do its job of limiting 3771 base current to 1 Amp(approx).
Can anyone explain purpose of CR5, or for that matter why R1 is made S.O.T by addition of R1X.
Thanks
http:
I aquired this broken 723 based PSU with blown components:-
CR1+2 35Amp diodes, 723 reg, q2, 3771 driver and diode CR5. I can easily repair, but cannot understand purpose of CR5. It apears to make circuit self destructive. If crowbar trips, output collapses. This causes 723 to drive high current thru be junction of Q2, CR5 and 2n3771. Current is NOT limited, as CR5 does not allow R1 (which is in parrallel) to do its job of limiting 3771 base current to 1 Amp(approx).
Can anyone explain purpose of CR5, or for that matter why R1 is made S.O.T by addition of R1X.
Thanks





RE: Explain purpose of this diode
What comes out of the 723 on pin 10 originates from what goes into pin 11.
And for your circuit, that's got R14 (330 ohms) limiting the current into pin 11.
RE: Explain purpose of this diode
Standby for others' input.
That's a nice power supply. Well worth fixing, especially since the parts are all garden variety and cheap.
RE: Explain purpose of this diode
Thanks Alvey
RE: Explain purpose of this diode
RE: Explain purpose of this diode
Regards alvey
RE: Explain purpose of this diode
RE: Explain purpose of this diode