03-29-2014, 10:25 AM
I put this on the bench last weekend, disassembled it and went to work.
One major mistake I made: I now feel it is imperative to test your audio output transistors before proceeding. I didn't.
More on that later.
I decided that on this one, I would replace every electrolytic capacitor and several of the paper/film caps as well.
This 700-T used four can-type electrolytics; two for the main power supply filters, and two as audio coupling caps to the speakers.
Taking what I learned from vintage radios, I rebuilt three of the four (for one, the replacement cap would not fit in the can but the replacement, a snap-in type, fit in the clip which holds it in place on the chassis).
Here's one of the audio coupling caps.
[Image: http://www.philcoradio.com/images/phorum...e00001.jpg]
The first thing to do is to carefully cut the can open, at the bottom but as close to the top of the flange (where the can's diameter is smaller) as possible. You'll see why shortly.
[Image: http://www.philcoradio.com/images/phorum...e00002.jpg]
Now, you are presented with the mess inside:
[Image: http://www.philcoradio.com/images/phorum...e00003.jpg]
Remove the old guts completely. Due to the size of the snap-in replacements, we need all of the room we can get.
[Image: http://www.philcoradio.com/images/phorum...e00004.jpg]
I drilled holes in the base, and added leads to the snap-in capacitor's terminals to go through these holes.
[Image: http://www.philcoradio.com/images/phorum...e00005.jpg]
Insert the new cap (make sure you get the polarity correct!) and close it all up, using glue to hold the can together. Notice how neatly the base fits into the top part, making use of that flange?
[Image: http://www.philcoradio.com/images/phorum...e00006.jpg]
Now, I reinstall the rebuilt cap in the receiver.
[Image: http://www.philcoradio.com/images/phorum...e00007.jpg]
The new one is on the right in this photo. The one on the left, as well as the input filter electrolytic, was rebuilt in a similar manner. These are held onto the receiver chassis with clamps, much like Philco electrolytics of the 1937-38 period, so it was important to reuse the old cans and mount the new caps as I did for space considerations.
One major mistake I made: I now feel it is imperative to test your audio output transistors before proceeding. I didn't.
More on that later.
I decided that on this one, I would replace every electrolytic capacitor and several of the paper/film caps as well.
This 700-T used four can-type electrolytics; two for the main power supply filters, and two as audio coupling caps to the speakers.
Taking what I learned from vintage radios, I rebuilt three of the four (for one, the replacement cap would not fit in the can but the replacement, a snap-in type, fit in the clip which holds it in place on the chassis).
Here's one of the audio coupling caps.
[Image: http://www.philcoradio.com/images/phorum...e00001.jpg]
The first thing to do is to carefully cut the can open, at the bottom but as close to the top of the flange (where the can's diameter is smaller) as possible. You'll see why shortly.
[Image: http://www.philcoradio.com/images/phorum...e00002.jpg]
Now, you are presented with the mess inside:
[Image: http://www.philcoradio.com/images/phorum...e00003.jpg]
Remove the old guts completely. Due to the size of the snap-in replacements, we need all of the room we can get.
[Image: http://www.philcoradio.com/images/phorum...e00004.jpg]
I drilled holes in the base, and added leads to the snap-in capacitor's terminals to go through these holes.
[Image: http://www.philcoradio.com/images/phorum...e00005.jpg]
Insert the new cap (make sure you get the polarity correct!) and close it all up, using glue to hold the can together. Notice how neatly the base fits into the top part, making use of that flange?
[Image: http://www.philcoradio.com/images/phorum...e00006.jpg]
Now, I reinstall the rebuilt cap in the receiver.
[Image: http://www.philcoradio.com/images/phorum...e00007.jpg]
The new one is on the right in this photo. The one on the left, as well as the input filter electrolytic, was rebuilt in a similar manner. These are held onto the receiver chassis with clamps, much like Philco electrolytics of the 1937-38 period, so it was important to reuse the old cans and mount the new caps as I did for space considerations.
--
Ron Ramirez
Ferdinand IN
