Re: [CAD_CAM_EDM_DRO] Re: Electronics gurus please help

I'm not laughing - I just hand soldered a 144 pin QFP device in the wrong
way round today! Now all I have to do is unsolder the horrible thing before
the boss finds out...

Les

> hi all,
>
> special thanks for all those who replyed. there was a lot of expertise,

understanding and encouraging in the mails.

>
> although i have already spent about 15 hours comparing this to that, that

to schematic, schematic to pcb, looking for cracks, etc, the replyes gave me
faith, that it can be done.

>
> so i sat down and inspired by the step by step comparision peter suggested

i started to compare the working and the bad circuit. at about the third
step i figured out, that

>
> maybe i should not tell this, as you all will find me a stupid beginner,

but it is fun to make others laugh

>
>
>
> so i had the IC inserted 180 degrees rotated. the footprint is totally

symmetric, (for 180 deg rotation) and it is not too easy to deduct which is
the pin1 from the datasheet (powertab sip15).

>
> fortunately (or thanks to the wise designers) (or damn designers) the IC

is even functionally nearly symmetrical, that helped me to make the error,
and also saved the life of the IC!!!

>
> that's all folks
>
> hope you enjoyed.
>
> vajk
>
>
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