Transformer part ID please

Tony Duell ard.p850ug1 at gmail.com
Tue Jan 24 00:06:58 CST 2017


On Mon, Jan 23, 2017 at 11:38 PM, Adrian Graham
<witchy at binarydinosaurs.co.uk> wrote:
> On 23/01/2017 21:38, "Tony Duell" <ard.p850ug1 at gmail.com> wrote:

>> Oh... The trace isn't open-circuit, is it? Check it with the
>> multimeter. Given the
>> corrosion damage to the tape drive I could well believe PCB problems of a
>> similar nature.
>
> I've measured resistance from all points to all points, there's 9:
>
> 74LS373 (output, new socket checked for solder bridges, new chip)
> 4x 2764 EPROM (new chips, no new sockets yet)
> MC3242A (new chip, no new socket yet, this one had bad verdigris)
> 74LS139
> 74LS21
> 74LS365
>
> and it's 0.6ohm max.

Are you telling me that if you put 2 logic analyser inputs on 2 points on the
same trace (which tests as continuous with an ohmmeter) that said 2 LA
channels don't show the same thing? If so, the LA needs repairing!

Given the problems I've had with even clean old sockets, I would have
replaced those. Corroded sockets must be worse. And I can't believe
they used turned-pin sockets in something like this.

-tony


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