05-20-2012, 06:12 PM
Just finished recapping the whole radio. Get a faint signal sometimes but a annoying motorboating sound comes and goes. Anything particular I should look for?
thanks
Chris
thanks
Chris
PT-7 motorboating
05-20-2012, 06:12 PM
Just finished recapping the whole radio. Get a faint signal sometimes but a annoying motorboating sound comes and goes. Anything particular I should look for?
thanks Chris
05-20-2012, 06:28 PM
The last one I restored had the same problem it turned out to be a way out of spec plate resistor. The best way to check your resistors is to use a decade box if you have one this way you wouldnt have to unsolder the suspected resistor, the box resistor will bypass the bad one if the resistance has drifted way to high.
Hope this helps, Todd
05-20-2012, 08:08 PM
Yes, there is a large paper capacitor, like a .22 microfarad, that will be tied between B- and the chassis, probably in series with a choke coil. That capacitor will also be paralled with a 220,000 resistor somewhere in the circuit. If that capacitor is open circuit the set will motorboat. It's also possible that the set needs an IF allignment, for some reason this can cause motorboating on a Philco. Another cause could be that the leads of the primary and secondary of an IF transformer may be crossed.
Regards Arran
05-24-2012, 07:14 PM
Thanks for the info. Will have to check out what you guys recommended.
thanks Chris
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