[Hallicrafters] SX-71 Bandswitch problem

[Phil Atchley]

I found the reason my antenna coils were "shorted".  It was just that, one
of the busbars from one of the coils to chassis ground was shorted to
another terminal where it went around the coil.  Apparently the wire had
been in that position since manufacture and finally shifted just "enough" to
actually touch the terminal, perhaps due to chassis flexing in shipment.  It
took very close examination to find it.

73 de Phil  KO6BB

> Hi Phil, a friend just finished restoring an SX 71 with the same problem.
> He turned it upside down while it was on and it worked! He found a broken
> tuning slug in the first stage off the antenna I believe. I don't have a
> schematic in front of me but it is the transformer associated with wafer
> 4 I think. If you look, it is the first tube and wafer on the left side
> of the page and the signal goes in that stage and you can switch to a
> position where that tube and transformer is bypassed. I hope this doesn't
> confuse things and if it would help I can get the tube and transformer
> I.D's and give to you. It would only work upside down when the slug fell
> to the top of the can. Good Luck!
> Bill
> W5ICS
>


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