Re: The whole Two Transistor Thing
I attempted repairing the 5vsb - replaced the shorted diode and both bulging capacitors with Nichicon PW caps. I measured the transformer and both transistors. All looked good. So powered it up ... a second or two pause ... then a loud bang with a nice fireball. Both transistors shorted!
This is why I hate troubleshooting those 2 transistor 5vsb circuits. EVERYTHING has to be just right or else. No telling what other problems were there, and now additional components bad. So I removed the heat sinks and 5vsb transformer to take some photos ..... now TWO burned areas.
IF I decide to repair this power supply - I will "Bestec" it - that is, gut the 5vsb circuitry and install a pwm chip for 5vsb circuit. Instead of blowing up, they just shut down when there is a problem.
I attempted repairing the 5vsb - replaced the shorted diode and both bulging capacitors with Nichicon PW caps. I measured the transformer and both transistors. All looked good. So powered it up ... a second or two pause ... then a loud bang with a nice fireball. Both transistors shorted!
This is why I hate troubleshooting those 2 transistor 5vsb circuits. EVERYTHING has to be just right or else. No telling what other problems were there, and now additional components bad. So I removed the heat sinks and 5vsb transformer to take some photos ..... now TWO burned areas.
IF I decide to repair this power supply - I will "Bestec" it - that is, gut the 5vsb circuitry and install a pwm chip for 5vsb circuit. Instead of blowing up, they just shut down when there is a problem.
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