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Fairlight III power consumption....

2015-08-13 by horizontal_productions@hotmail.com

Hi all. Seeing your recent thread, I thought I'd add some info. I had to replace the digital power supplies from two CMI IIIs, and since I've never seen it written down, I thought I'd monitor the power consumed by each card. The numbers are in amps, correct to about 100mA. As you'll remember from your physics lectures, multiply these numbers by 5 (volts) to give you Watts. All those Watts are turned into heat!

CMI-39 (2Mb RAM) 0.70, CMI-43 (8Mb RAM) 0.15, WFM-32 (my 32Mb RAM) 0.40, CMI-31 2.23, CMI-32 0.98, TS-1 1.86, CMI-41 2.22, CMI-28 1.47, Q-356 1.10, Q-133 1.29, Q-209 1.79, CG-3 2.58, Q-007 0.01.

I also checked the currents when the cards were (extremely) busy, using the memory diagnostics, and surprisingly, there wasn't much difference from quiescent. So if you have 7 x 2Mb RAM cards, you're putting out around 25 Watts of heat just for memory ... Regards, PW Sydney.

Re: [Fairlight-CMI] Fairlight III power consumption....

2015-08-13 by Joe Sleator

Far in the future, some extraterrestrials are picking through some relics on Earth and discover a CMI Series III.

They figure out how to power it up, and begin to ponder its intended purpose.

One says "It';s blowing a lot of air around...and it's quite heavy and solidly built!"

The second one says "It makes these quaint vibrations in the air, too, I wonder what their purpose is?"

The third one says "I believe it's some kind of heater; It converts electricity into heat, and stores a small amount of information for the user's convenience. The sound it produces is incidental, just so the user knows it's properly making heat!"

Joe

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On Thu, Aug 13, 2015 at 6:22 PM, horizontal_productions@hotmail.com [Fairlight-CMI] <Fairlight-CMI@yahoogroups.com> wrote:

Hi all. Seeing your recent thread, I thought I'd add some info. I had to replace the digital power supplies from two CMI IIIs, and since I've never seen it written down, I thought I'd monitor the power consumed by each card. The numbers are in amps, correct to about 100mA. As you'll remember from your physics lectures, multiply these numbers by 5 (volts) to give you Watts. All those Watts are turned into heat!

CMI-39 (2Mb RAM) 0.70, CMI-43 (8Mb RAM) 0.15, WFM-32 (my 32Mb RAM) 0.40, CMI-31 2.23, CMI-32 0.98, TS-1 1.86, CMI-41 2.22, CMI-28 1.47, Q-356 1.10, Q-133 1.29, Q-209 1.79, CG-3 2.58, Q-007 0.01.

I also checked the currents when the cards were (extremely) busy, using the memory diagnostics, and surprisingly, there wasn't much difference from quiescent. So if you have 7 x 2Mb RAM cards, you're putting out around 25 Watts of heat just for memory ... Regards, PW Sydney.