03-29-2013, 11:55 PM
OK, the shadograph came back (I posted some prelim. results in the thread about it).
Here's what I don't get:
1. At some point of the discussion about this Philco it was suggested it is the ver. 124. Which it probably is as the volume control hookup (different between the two and in my case it looks like 124 one) seems to confirm that.
Now correct me if I am wrong but the 124 does not have the band switch.
Well, mine does.
2. Also 124 shows a bypass 2.9K resistor across the shadograph, and mine did not have it.
So I am a bit confused which version I have.
In any case, I disconnected the 3K resistor I installed in parallel to the shadowhgraph, and it did not make a whole lot of difference.
It works but I thought it'd get more narrow. When the radio tunes to the local station the shadow becomes about 5mm (0.2").
I have zero experience with these so I don't know if it is normal or should I try for a better result.
And, it seems like while doing all that I found I have something akin to a bad connection. While tuning in I have sometimes temporary jump in volume and the shadow meter gets narrower. This seems to correspond with the area where the tuning cap is and the tube onits right. When rocking the tube I got that same result but then tuning cap behaves similar. I cleaned the panel with Deoxit, did not help.
Oh well, I'll figure it out tomorrow.
And one more question:
The tone control regulator shows (in 124) the switch as part 53 and three caps as part 54. When referring to the BOM for the 54 it will say "condensers inside 53". However I have the part 54 shown as a backelite cap at the chassis bottom view (and it is there). It is indeed connected as the first out of the three caps on the left (0.05uF) on the schematic.
Here's what I don't get:
1. At some point of the discussion about this Philco it was suggested it is the ver. 124. Which it probably is as the volume control hookup (different between the two and in my case it looks like 124 one) seems to confirm that.
Now correct me if I am wrong but the 124 does not have the band switch.
Well, mine does.
2. Also 124 shows a bypass 2.9K resistor across the shadograph, and mine did not have it.
So I am a bit confused which version I have.
In any case, I disconnected the 3K resistor I installed in parallel to the shadowhgraph, and it did not make a whole lot of difference.
It works but I thought it'd get more narrow. When the radio tunes to the local station the shadow becomes about 5mm (0.2").
I have zero experience with these so I don't know if it is normal or should I try for a better result.
And, it seems like while doing all that I found I have something akin to a bad connection. While tuning in I have sometimes temporary jump in volume and the shadow meter gets narrower. This seems to correspond with the area where the tuning cap is and the tube onits right. When rocking the tube I got that same result but then tuning cap behaves similar. I cleaned the panel with Deoxit, did not help.
Oh well, I'll figure it out tomorrow.
And one more question:
The tone control regulator shows (in 124) the switch as part 53 and three caps as part 54. When referring to the BOM for the 54 it will say "condensers inside 53". However I have the part 54 shown as a backelite cap at the chassis bottom view (and it is there). It is indeed connected as the first out of the three caps on the left (0.05uF) on the schematic.