MS-TECH SP-680 troubleshooting

[yokoono]

I have a power supply MS-TECH SP-680 (Germany)
What transistors there are in primary circuit (high voltage)?.
Don"t work with normal transistors (NPN).
Trafo driver is EEL-16 HAJ086.

[370forlife]

Re: MS-TECH SP-680 troubleshooting

Picture would help alot. If it is a half bridge design, it takes two NPN BJT switching transistors. If it is a real 680W, I would imagine it is either single transistor forward with two MOSFET transistors running in parallel or uses two transistor forward with just two MOSFET transistors.

[yokoono]

Re: MS-TECH SP-680 troubleshooting

Controller pwm TL494 -2 transistors C945 -driver EEL-16 HAJ086 -2 power transistors(?)
With 2 power transistors NPN I not have 12- 5-3,3V.