Author Topic: ISA card power analyser  (Read 971 times)

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Offline HwAoRrDk

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ISA card power analyser
« on: June 10, 2021, 06:02:30 pm »
Had an odd thought the other day. Has there ever been, or currently exists, a device which allows the power consumption of an ISA card to be analysed?

I know there are some POST diagnostic cards that also display voltage levels on the ISA bus, but this is not what I'm thinking of. I'm thinking of something that shows current consumption - that is, how many milliamps/amps are being drawn by a card from the +5/-5/+12/-12 volt supplies.

I was envisaging something like an interposer/riser card that measures the current draw of whatever actual ISA expansion card is plugged into it, and shows a figure for each voltage rail on something like a 7-segment display. Maybe even something that has also spits the measured values out over a serial connection (UART, or maybe even RS232 for connection to the host PC itself) for logging, etc.

Useless idea or not? Could make a fun little project regardless of utility... ;D

Also, anybody got any idea of the current limits for each voltage rail on an ISA slot? Best I could find with a brief search was the electrical specifications in the EISA standard, which gave the following:

+5 Volts - 4.5 amps
-5 Volts - 2 amps
+12 Volts - 1.5 amps
-12 Volts - 3 amps

Offline David Hess

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Re: ISA card power analyser
« Reply #1 on: June 11, 2021, 03:16:13 am »
I remember seeing ISA interposers which included jumpers for adding current shunts for current measurement of the various supplies.  That would make it an optional and little used feature.


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