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From: Bob F <bobnospam@gmail.com>
Newsgroups: sci.electronics.repair
Subject: Re: Altec Lansing ATP3 Speaker system transformer failed.
Date: Mon, 29 Apr 2024 09:43:50 -0700
Organization: A noiseless patient Spider
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On 4/29/2024 1:28 AM, Liz Tuddenham wrote:
> Bob F <bobnospam@gmail.com> wrote:
> 
> [...]
>> No output. Ohmmeter resistance shows infinite on primary and secondary.
>> 2 leads on primary, 2 on secondary, going to 4 diodes on the circuit board.
> 
> Does it look badly burnt or is there no physical sign of stress?

No sign of either. I just pulled out the circuit board, and no visual 
sign of damage. The diodes and cap on the power input to the board test OK.

> 
> It would be very unlikely that both windings would go O/C simultaneously
> unless it had failed catastrophically and that would be rather obvious
> from the outside.

Kind of weird. It worked one day, but not at all the following morning.

> 
> Simple question:  Did you measure the resistance between the two ends of
> the same winding or are the terminals laid out in a confusing way, so
> you measured resistance between two different windings?

I measured across the wires going toward the power cord for the primary, 
and the wires going to the circuit board for the secondary. 2 pairs of 
wires completely different wires, one pair from each side.

I moved a system that used to be used in my exercise room up, and it fit 
in my space, so no crisis. Maybe I will try unwinding the transformer 
coil some time I'm feeling bored.