Quote:
Originally Posted by bigus01
Is the link at 4 & 5 a permanent link, as without it I have no mic.
Regards
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No. This link is currently shorting out your dial pulse contacts, and allowing current through the telephone line loop of dial pulse contacts, mic, ASTIC primary winding, gravity-switch contact and return line.
It sounds like your dial pulse contacts, which are normally closed, are high-resistance and not allowing sufficient current through to power your T21A mic. You'll need to clean them. Over the years they'll've become pitted with sparking.
I would use a thin strip of rough paper (blotting paper) and, with your fingers gently squeezing the contacts together, draw the paper through back and forth a few dozen times. But ensure that they are actually making contact when the dial is at rest.
Another thing it could be is a dodgy pink or orange wire between dial and dial terminal strip, especially the little bound loop connectors at the ends. They may be hanging on a thread or so or otherwise H/R. I've known me having to change some of them out. Your telephone, being the older model, has cotton-covered insulation rather than PVC.
That's the area to focus on next. It can be magnifying-glass stuff!