06-18-2018, 11:41 PM
Thanks guys.
@Ron - I will definitely try out the 2M value once things are running otherwise.
@Mike - Ah right! I found it: http://philcoradio.com/phorum/showthread.php?tid=17679
I should've looked earlier.
Here's where I'm at so far:
BC Resistor
The 160 ohm and 1K sections of the BC resistor were open. I created a new BC resistor out of 25W resistors. I was lucky in that the three resistors *just barely* fit.
4K resistor w/ tap: 2240 ohm + 1540 ohm sections
160 ohm Philco part
1K resistor
[Image: https://farm2.staticflickr.com/1732/2899...0b81_c.jpg]
I brought it up on the variac and it actually received quite a bit at ~80VAC.
I was fortunate that the RF coils all tested good.
Recap
I replaced the big filter can caps. Boy that was a pain to get out. The tar had previously partially melted - making it stick really well to the sides of the can.
I relied on the trick described elsewhere on the Phorum of driving a screw into the tar block (to pull on) and then heating the sides of the can with a heat gun until I could get the block out.
I also used a small thin pry bar I have to separate it from the edge of the can. It took a little of everything but eventually it came free.
[Image: https://farm2.staticflickr.com/1758/4196...0754_c.jpg]
I also replaced the 0.1uF caps inside the 100 ohm wirewound resistor tubes. Kept the original resistance wire around the tube.
Interstage Transformer
The secondary of part #26 was 1/2 open. I believe that someone long ago someone worked around that problem with this?
[Image: https://farm2.staticflickr.com/1748/4196...f890_c.jpg]
The transformer with the open winding is in the top-right of the picture.
It actually did work reasonably well the way it was (decent volume, but a bit of distortion). I was able to find a replacement transformer on oldradioparts.com so I ordered that.
I'm about to swap that in. I did measure ~6,000 ohm for the secondary. I wonder if I'll get that hum you described now that the two caps / resistors work-around is removed.
@Ron - I will definitely try out the 2M value once things are running otherwise.
@Mike - Ah right! I found it: http://philcoradio.com/phorum/showthread.php?tid=17679
I should've looked earlier.
Here's where I'm at so far:
BC Resistor
The 160 ohm and 1K sections of the BC resistor were open. I created a new BC resistor out of 25W resistors. I was lucky in that the three resistors *just barely* fit.
4K resistor w/ tap: 2240 ohm + 1540 ohm sections
160 ohm Philco part
1K resistor
[Image: https://farm2.staticflickr.com/1732/2899...0b81_c.jpg]
I brought it up on the variac and it actually received quite a bit at ~80VAC.
I was fortunate that the RF coils all tested good.
Recap
I replaced the big filter can caps. Boy that was a pain to get out. The tar had previously partially melted - making it stick really well to the sides of the can.
I relied on the trick described elsewhere on the Phorum of driving a screw into the tar block (to pull on) and then heating the sides of the can with a heat gun until I could get the block out.
I also used a small thin pry bar I have to separate it from the edge of the can. It took a little of everything but eventually it came free.
[Image: https://farm2.staticflickr.com/1758/4196...0754_c.jpg]
I also replaced the 0.1uF caps inside the 100 ohm wirewound resistor tubes. Kept the original resistance wire around the tube.
Interstage Transformer
The secondary of part #26 was 1/2 open. I believe that someone long ago someone worked around that problem with this?
[Image: https://farm2.staticflickr.com/1748/4196...f890_c.jpg]
The transformer with the open winding is in the top-right of the picture.
It actually did work reasonably well the way it was (decent volume, but a bit of distortion). I was able to find a replacement transformer on oldradioparts.com so I ordered that.
I'm about to swap that in. I did measure ~6,000 ohm for the secondary. I wonder if I'll get that hum you described now that the two caps / resistors work-around is removed.
