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Dumb question please: Power load requirement for an Apple II with one disk drive and a few cards

Submitted by arukum17 on May 15, 2008 - 6:42am. Apple II

A new user from the UK seeks your help:

I have to use a transformer to change my UK voltage of 240V to an US voltage of 120V so that I can use my Apple II (non plus)
The transformer is rated as having a maximum load of 30 volt-amps. Is this OK for an Apple II power supply or will I run into problems.

Wanted to double check before I goofed up royally!
Sorry if the question is a dumb one.

Arun

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The power supply is rated for

Submitted by mfortuna on May 16, 2008 - 11:08am.

The power supply is rated for 60W full-load and 79W peak load. If I'm reading the reference manual right each of the slots is allowed about 1.1W (8.9W total). At 80% efficiency each slot is about 1.4W (11.1W total).

It's good practice to have headroom in your power subsystem, I have no idea what Apple used. With 20% margin the total power would be 48W, subtract all peripheral cards and you get 37W. So I think your 30V-A transformer is a little low. You may want to find one that is closer to 60W.

Mike

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Thanks very helpful...thanks

Submitted by arukum17 on May 16, 2008 - 3:11pm.

Thanks very helpful...thanks Mike

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This does not work in the UK

Submitted by arukum17 on May 17, 2008 - 1:04pm.

This does not work in the UK with a 100 Watt transformer nor a 30 watt transformer.

With a small appliance transformer that is rated from 50 Watt and above, is plugged in the power supply inside the Apple II gives a humming noise but the computer does not switch on. No humming noise from the Apple II when the 100 watt transformer is plugged in.

This computer worked when the seller shipped it to me from the USA... what should I do?

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I believe the issue is with t

Submitted by arukum17 on May 18, 2008 - 1:21pm.

I believe the issue is with the frequency UK(50Hz) will not drive a US(60Hz) power supply
I need to replace the power supply with a Europlus unit

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I'm almost certain the freque

Submitted by mfortuna on May 19, 2008 - 11:03am.

I'm almost certain the frequency is not an issue. The power supply should work at either 50 or 60Hz. Does the keyboard light come on?

If you were very careful you could use a PC type power supply with your Apple. You would have to cut the input harness off the Apple power supply and then splice in the PC supply.

I think your first step would be measuring the voltages on the main board. If they are present, something else is wrong. Make sure any IO cards you have are secure.

Mike

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Keyboard light is fused so ca

Submitted by arukum17 on May 19, 2008 - 5:20pm.

The output plug from the Apple internal power supply gives no voltage

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