Thread: Power questions
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Old 05-26-2007, 11:54 PM
Grant Stockly Grant Stockly is offline
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Until you "trim" the power supplies they will be 7.5vDC and +/- 15vDC. On each power supply there is a pot to adjust the voltage. I found it runs fine on +7.5 and +15/-15. The vintage Altair used a linear power supply that when loaded down will have a dropping output voltage. The switching power supplies drive hard at 7.5v until overloaded.

On some of the vintage units the unloaded voltage of the +8v line was +12v to handle TONS of cards. This causes a problem when someone buys one of these units off of ebay (or any second hand place) and wants to test the system with only a CPU card and memory card. They over heat and go POOF. : )

The switching power supplies eliminate this worry. : )


The MITS manual says things like "+5v" because that is what the voltage will be after regulating... You might find a few different descriptions of the power lines in different places of the manual. Do you have close up pictures of how I wired my power supplies? In the manual?
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