12-10-2013, 05:02 PM
I just arrived home from work, so I'll do what I can...
Q1. What about the wirewound multitap resistor? What exactly are you needing to know about it?
If you look at this schematic, it lists the resistance values of the various sections along with part values of the other resistors (and capacitors).
Q2. I still haven't found some of my books after moving. You can probably use a 2.5 mH RF choke to replace (52).
Q3. Both (17) and (22) should be 350 pF (0.00035 uF). The extra 0 for the cap (17) is a typo.
Q4. See the 90 schematic with two 45 tubes on my website.
http://www.philcoradio.com/tech/images/90a.jpg
Q5. Yup, the original is listed as .001 uF. I would say that the Philco engineers selected a low value as this is coming off the pi filter containing the RF choke. You are comparing apples to oranges in comparing this circuit to that of the 1-47 90 and the 2-47 90 since the later two versions used AVC and a 27 tube connected as a diode as a 2nd detector instead of a 24 tube hooked up as the infamous "power detector" (high distortion).
But I am no engineer, nor do I play one on TV.
As for the question in your last post, sorry but I no longer own a 90 with two 45 tubes.
Both of my 90 chassis are 1-47.
Q1. What about the wirewound multitap resistor? What exactly are you needing to know about it?
If you look at this schematic, it lists the resistance values of the various sections along with part values of the other resistors (and capacitors).
Q2. I still haven't found some of my books after moving. You can probably use a 2.5 mH RF choke to replace (52).
Q3. Both (17) and (22) should be 350 pF (0.00035 uF). The extra 0 for the cap (17) is a typo.
Q4. See the 90 schematic with two 45 tubes on my website.
http://www.philcoradio.com/tech/images/90a.jpg
Q5. Yup, the original is listed as .001 uF. I would say that the Philco engineers selected a low value as this is coming off the pi filter containing the RF choke. You are comparing apples to oranges in comparing this circuit to that of the 1-47 90 and the 2-47 90 since the later two versions used AVC and a 27 tube connected as a diode as a 2nd detector instead of a 24 tube hooked up as the infamous "power detector" (high distortion).
But I am no engineer, nor do I play one on TV.
As for the question in your last post, sorry but I no longer own a 90 with two 45 tubes.
Both of my 90 chassis are 1-47.
--
Ron Ramirez
Ferdinand IN
