Hi,
I'm having a problem with the power supply voltages in a MC250. The DC voltages are way too high. I have the power supply isolated and the bridge that is fed by the green wires from the transformer is fine. However, the bridge fed by the red wires is is way off. The AC voltage of the red wires is 160VAC and and the -44VDC is measuring -108VDC and the +93VDC is measuring 110VDC. I replaced the diodes, capacitors, and resistors. Any ideas-I'm guessing that the AC out of the power transformer is wrong but I don't know.
I'm having a problem with the power supply voltages in a MC250. The DC voltages are way too high. I have the power supply isolated and the bridge that is fed by the green wires from the transformer is fine. However, the bridge fed by the red wires is is way off. The AC voltage of the red wires is 160VAC and and the -44VDC is measuring -108VDC and the +93VDC is measuring 110VDC. I replaced the diodes, capacitors, and resistors. Any ideas-I'm guessing that the AC out of the power transformer is wrong but I don't know.
Welcome to diyAudio Horace 
Your definitely going to be better asking this question in the appropriate forum which would be solid state for the MC250 but to get you started I would suggest that any DC voltages could rise substantially off load (nothing drawing current). 93 to 110 volts sounds in that range, -44 to -108 doesn't and suggests that rail may be a low current auxiliary supply.... but without knowing the amp or circuit that's all guesswork on my part
Your definitely going to be better asking this question in the appropriate forum which would be solid state for the MC250 but to get you started I would suggest that any DC voltages could rise substantially off load (nothing drawing current). 93 to 110 volts sounds in that range, -44 to -108 doesn't and suggests that rail may be a low current auxiliary supply.... but without knowing the amp or circuit that's all guesswork on my part
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.