Terry, I saw that.. After I posted this.. I did disconnect the leads from the Tuning cap and all looked good. However When I put back together I still get the same thing Scratchy when tuned across the band.. I tried the IF alignment but that didn't help.. I also tried some different 6A8 tubes .. No help there either.. I can only RX 1440 Am but with load hum on signal. No signals anywhere else ..The OSC is working OK..
03-20-2017, 04:47 PM
(This post was last modified: 03-20-2017, 04:51 PM by Radioroslyn.)
>The OSC is working OK
How do you know this???[Image: http://philcoradio.com/phorum/images/smi...roblem.gif
]. Can you hear it or check it w/a counter???
If so then the issue is in the ant circuit. Hum may be from a open gnd connection at the ant coil. Check the volume control (rf/IF gain). Clean the brass rotor ground fork at the rear of the tuning to rid yourself of the tuning noise.
A man who has a clock knows what time it is. A man with two clocks can never be sure
Terry, Osc is working. Checked it with a portable AM receiver. At 600 KC on dial I RX Osc at 1065KC.. and so on up the band. I will check the Grounds. I did notice that the volume has to be almost all the way up to hear anything.. And the 465KHZ signal from generator has to be pretty high to hear it. About 0 DBM.. So looks like not much IF gain.. Do you need a schematic ?
Ok After looking the radio over again and measuring the Tuning Cap I found a spot where it was reading a Short.. actually 2 spots.. Looked at it closely and found 2 Plates touching.. After I fixed that the scratching noise went away. Realigned the IF and RF and radio now works. Not really that sensitive but OK.. Was hearing CHU Canada on 3.330 Mhz so not to bad.. AM worked pretty good as a Canadian station at 740 KHZ was coming in .. Had to use a long antenna as this doesn't have a loop built in..
So now to put back into cabinet and make sure dial is set correctly...
If the volume is a bit low, check the plate load resistor on the first audio tube, probably a 6Q7 or something like that. If it's a bid deaf in the front end I would start checking mica caps if the resistors have all been checked.