Klyball
Experienced Member
I'm trying to repair a cal DC power supply and am hoping to verify some components , before troubleshooting further .
supply would blow fuse on power up, looked to be a bad Q1 and Q2
Q1 was marked j31007 with makes sense to be a mje13007 Q2 is marked U30 , it is more then likely a cal dc part code as was the way then.
Q2 is a to-126 package so I was thinking a 13002 or 13003
I replaced Q1 with a 13007 and Q2 with a 13002 applied power and click click boom
Q1 is a BCE and Q2 is ECB well the 13002 I used was BCE
replaced
R9 = 100ohm 1/4w
R6 = 750ohm 1/4w
R4 = 47ohm 3w
R28= .47ohm 2w
Q1 = MJE13007
Q2 = ST13003 ECB
Applied power Click Click Click no Boom, reading 5v ,12v -12v no load
if I apply load slower click 5v = 0 to 3, 12v and -12 = 0
Q2 is probably the problem but not that familiar with power supply design
I'm hoping someone might have a unit with a real part # for Q1 and Q2 and verify R9 and R6
here is a image of a similar supply , mine is blue but components are the same
supply would blow fuse on power up, looked to be a bad Q1 and Q2
Q1 was marked j31007 with makes sense to be a mje13007 Q2 is marked U30 , it is more then likely a cal dc part code as was the way then.
Q2 is a to-126 package so I was thinking a 13002 or 13003
I replaced Q1 with a 13007 and Q2 with a 13002 applied power and click click boom
Q1 is a BCE and Q2 is ECB well the 13002 I used was BCE
replaced
R9 = 100ohm 1/4w
R6 = 750ohm 1/4w
R4 = 47ohm 3w
R28= .47ohm 2w
Q1 = MJE13007
Q2 = ST13003 ECB
Applied power Click Click Click no Boom, reading 5v ,12v -12v no load
if I apply load slower click 5v = 0 to 3, 12v and -12 = 0
Q2 is probably the problem but not that familiar with power supply design
I'm hoping someone might have a unit with a real part # for Q1 and Q2 and verify R9 and R6
here is a image of a similar supply , mine is blue but components are the same
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