07-26-2009, 04:14 PM
I am working on a Philco 60 cathedral. The seller had marked it "late" version. Serial number is G65194. The schematic differs from Riders and the Philco service information I have. Unlike Riders, it has 4 IF trimmers, and a fixed capacitor rather than a police band adjustable padder. The mica capacitor shunts the broadcast padder when switched to Police band. It is good, measures 1320pf but has color dots red/brown/red? The radio works great on broadcast band. It has been recapped, all resistors and tubes checked, etc. But there is NO reception on Police band.
The bandswitch shorts out a portion of the antenna and oscillator coils on the Police band. It is working. The antenna coil secondary measure 6.8 ohms on BC and 2.1 ohms on Police. The oscillator coil measures 2.7 ohms on BC and 1.4 on Police. On Police, a fixed capacitor is also shunted across the BC padder.
With that capacitor in place, I get NO reception on Police. I tried substitution and other values - no luck. If the shunt padder is removed, I get some reception. With the dial at 1500, it receives 1500. Dial at 1600, receives 1560. Dial at 1700, receives 1600. Dial at 1800, receives 1675. No reception past 1850 - even with the signal generator cranking out maximum voltage. So it is obviously NOT tracking properly. There are no police band alignment adjustments that I can find.
The radio has seen some "servicing" in the past, so I'm no sure what is original and what is not.
Does anyone have any ideas on what to try next? Do any of you have a working version of this set (with the variations mentioned above)? I'd really be interested in finding out the correct value of the police band fixed padder.
Thanks
The bandswitch shorts out a portion of the antenna and oscillator coils on the Police band. It is working. The antenna coil secondary measure 6.8 ohms on BC and 2.1 ohms on Police. The oscillator coil measures 2.7 ohms on BC and 1.4 on Police. On Police, a fixed capacitor is also shunted across the BC padder.
With that capacitor in place, I get NO reception on Police. I tried substitution and other values - no luck. If the shunt padder is removed, I get some reception. With the dial at 1500, it receives 1500. Dial at 1600, receives 1560. Dial at 1700, receives 1600. Dial at 1800, receives 1675. No reception past 1850 - even with the signal generator cranking out maximum voltage. So it is obviously NOT tracking properly. There are no police band alignment adjustments that I can find.
The radio has seen some "servicing" in the past, so I'm no sure what is original and what is not.
Does anyone have any ideas on what to try next? Do any of you have a working version of this set (with the variations mentioned above)? I'd really be interested in finding out the correct value of the police band fixed padder.
Thanks
