Apple 1 - Power Supply - Crackling/Burning Smell from Transformer

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Apple 1 - Power Supply - Crackling/Burning Smell from Transformer

Hello A1ers,

 

I have been working on bringing up an Apple 1.  At this point, the system now will power on, display video and echo input from the keyboard.

 

The last time that I powered the system on, I heard a crackling sound and smelled a burning odor from one of the transformers after roughly a minute of operation.   I immediately powered down the system, let it cool and then tried powering it up again with the same result.   The transformers are the original pair of Triads that the system came with. 

 

Has anyone else experienced this problem or have any suggestions about what might be wrong?

 

I've attached a photo of the power connector to the board.  Can anyone take a look at this and confirm if the wire positions look correct on the plug?

 

Thanks

_Buckminster

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Hello,

Hello,

 

I think that the power suplly wires are not  properly plugged in

 

According the A1 manual, page 11, you need to connect:

Stancor P-8380 (bigger) - positions 1 and 2

Stancor P-8667 (smaller) - positions 3, 4 e 5

On position 6, you don´t need to connect any wire.

 

Look at my blog (besides the fact that is in portuguese) and you can see my pictures of the transformers:

 

http://www.vintageretrostyle.com/2019/01/construindo-um-classico-apple-1-parte-4.html

 

Sorry for my english. I wish that this can help you.

 

Evandro

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Correct Page

The correct page on manual is 8 - but is 11 on manual PDF. Thanks

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Actually that might be a good

Actually that might be a good catch, I didn't look at this thread till now since he had sent me an email without pic.   I just happen to click on the thread as a quick way to get into the Apple-1 forum are since it was in the active topics.

 

FYI: pin 5 and 6 are connected on the board so it could be an issue depending on which wires are both going to 5 and 6.    So the order should be 1,2 to the F31X and 3,4,5 (or 3,4,6) to the F40X transfomers.  He is using triad not stancor so I am using those part numbers here.

 

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Thanks for the Advice and Input

Thanks for the input and advice.  I have a pair of new Triad F-31X and F-40X transformers that I'm going to hook up based on the wiring that you suggested.  I'll keep you posted if this seems to solve the problem.

 

Best

_Buckminster

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