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IBM 5150/5155/5160  -  MDC  -  Using an AT-Class Power Supply


Possible problem #1

Background

The power supplies used in the IBM 5150/5155/5160 are power supplies of the switch mode type.

To operate, most of those vintage power supplies require a minimum amount of loading.  And different make-models require a different amount of loading.

Possible problem

The 'minimum diagnostic configuration' procedure that you are about to run, has only the IBM 5150/5155/5160 motherboard connected to the power supply.  That is done for a very good reason; we do not want something else to possibly interfere with what we are doing.

An IBM 5150/5155/5160 motherboard alone, is in the vast majority of cases, adequate loading for a PC/XT-class power supply, but a question becomes, is it enough for some AT-class power supplies.

So, keep the aforementioned in mind if you are using an AT-class power supply for the 'minimum diagnostic configuration' procedure.  You may need to add extra loading on the power supply, perhaps an IDE drive, or two.


Possible problem #2

Background

-5V is critical to the 16KB-64KB version of IBM 5150 motherboard.

Possible problem

Some ATX power supplies have no -5V output.  Therefore, their use, with an adapter, to power the 16KB-64KB version of IBM 5150 motherboard, will not work.