Ttpilot
Experienced Member
This is to follow up on a thread I started a while back about my dead North Star Horizon motherboard. After repairing the traces and a bad resistor, I decided to replace the original linear power supply with a switching power supply, specifically a Meanwell HRP-75-7.5 and two RS-15-15s. That's what I'm using to power my Altair 8800c. Each power supply checks out okay when I measure the voltages, which are calibrated to +8v, +16v, and -16v. When plugged into the quick connect lugs on the motherboard I get a strange result. The +8v supply is fine, including the +5v supply derived from it. However, neither 16v line shows any life, either at the lugs or anywhere else in the circuit. They're plugged into the correct quick connect lugs, and I know power is coming out of the power supply units, so I'm confused as to why nothing shows up on the motherboard
Suggestions welcome!
Suggestions welcome!