I had to repair this unit for my son (no flamethrowers about Bose please). The power supply was completely dead but the fuse was OK. I found the obvious problem of the two blown mosfets in the SMPS (chunks missing) along with 4 resistors and the controller IC in the same condition. As long as I was in there I replaced some of the nearby components that might have been stressed or tested marginal/bad in circuit. Here’s the final list of components if anyone has to dive deeply into one of these:
U101 = L6598D controller IC
U102 = CNY17F-1 Opto
U103 = CNY17F-1 Opto
C117 = 1uF
C118 = 10uF
C119 = 0.47uF film
R101 = 10 ohm
R102 = 33 ohm
R103 = 10 ohm
R104 = 100 ohm
Q101 = STP9NB50FP (installed 2SK3569) Mosfet
Q102 = STP9NB50FP (installed 2SK3569) Mosfet
Q103 = K72 (2N7002) (installed 702 = 2N7002) Mosfet
Q104 = K3N (MMBT3906) (installed 2A = MMBT3906) BJT
D101 = KA6 (BAS16) (installed A6 = BAS16) Diode
D102 = KA6 (BAS16) (installed A6 = BAS16) Diode
D150 = KJJ = BAV70 (installed A4 = BAV70) Double Diode
ZR101 = KY2 = BZX84C12 (installed Y2 = BZX84C12) Zener Diode
ZR102 = KY2 = BZX84C12 (installed Y2 = BZX84C12) Zener Diode
ZR103 = KZE = BZX84C3V3 (installed Z14 = BZX84C3V3) Zener Diode
The first time through, it didn’t come to life. Checking components, found that D150 had one leg shorted. I hadn’t checked it because it appeared to be outside of the ‘blast zone’ but once I replaced it, everything worked as it should. I’ve attached a couple of photos and the schematic for reference . . . . Enjoy.
U101 = L6598D controller IC
U102 = CNY17F-1 Opto
U103 = CNY17F-1 Opto
C117 = 1uF
C118 = 10uF
C119 = 0.47uF film
R101 = 10 ohm
R102 = 33 ohm
R103 = 10 ohm
R104 = 100 ohm
Q101 = STP9NB50FP (installed 2SK3569) Mosfet
Q102 = STP9NB50FP (installed 2SK3569) Mosfet
Q103 = K72 (2N7002) (installed 702 = 2N7002) Mosfet
Q104 = K3N (MMBT3906) (installed 2A = MMBT3906) BJT
D101 = KA6 (BAS16) (installed A6 = BAS16) Diode
D102 = KA6 (BAS16) (installed A6 = BAS16) Diode
D150 = KJJ = BAV70 (installed A4 = BAV70) Double Diode
ZR101 = KY2 = BZX84C12 (installed Y2 = BZX84C12) Zener Diode
ZR102 = KY2 = BZX84C12 (installed Y2 = BZX84C12) Zener Diode
ZR103 = KZE = BZX84C3V3 (installed Z14 = BZX84C3V3) Zener Diode
The first time through, it didn’t come to life. Checking components, found that D150 had one leg shorted. I hadn’t checked it because it appeared to be outside of the ‘blast zone’ but once I replaced it, everything worked as it should. I’ve attached a couple of photos and the schematic for reference . . . . Enjoy.