1. The PHILCO Phorum
  2. Philco Radio Discussions
  3. Philco Electronic Restoration

Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Linear Mode
I may have goofed...
Chuck Schwark
Phorum Expert
*****
Posts: 1,703
Threads: 55
Joined: Sep 2005
City: Evanston, IL
#2

03-02-2006, 10:00 AM
Most probably. Cap 15 is the RF tube plate bypass cap on the B+ line.


Caps 6 and 13 are on the AVC buss. Cap 6 is for bypassing and cap 13 is the time-constant/filter cap in conjunction with resistor 34.

They "filter" out the audio freqs on the AVC buss which is only the DC component of the deteced signal. Too little filtering (or too short a time-constant) lets the AVC buss "bobble" up and down in time to the audio causing wild gain shifts making the detected signal jumpy which again makes the AVC buss even more jumpy, etc....
Chuck Schwark,
The Philco Repair Bench
[Image: http://www.philcorepairbench.com/images/philog3tiny.gif]
http://www.philcorepairbench.com
Website Find
« Next Oldest | Next Newest »
Thread Closed


Messages In This Thread
I may have goofed... - by Robbie Roberts - 03-02-2006, 01:48 AM
[No subject] - by Chuck Schwark - 03-02-2006, 10:00 AM
[No subject] - by Robbie Roberts - 03-02-2006, 10:33 AM
[No subject] - by Chuck Schwark - 03-02-2006, 10:44 AM
[No subject] - by Robbie Roberts - 03-02-2006, 10:53 AM
[No subject] - by Chuck Schwark - 03-02-2006, 11:37 AM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 91 Schematic
Hi Rod, The resistor connects to pin 4 and the ungrounded side of block 9. From pin 9 of the RF tube to one side of ...dconant — 09:34 AM
Just got a 49-1613 need to know...everything!
I just found your post. I have this exact same model, and have had it since 1985 when I was 15 years old! I performed a ...MuzzcoVW — 09:11 AM
B&K 1077B no video
Hello Tim, I would if it's a leaky Capacitor So are all 3 of those B- voltages low then ? Sincerely Richardradiorich — 01:55 AM
B&K 1077B no video
I found a schematic and think I have the problem traced down to the minus power supply. I have very low voltages that go...TV MAN — 12:41 AM
RCA 15X
I'd try replacing the bulb first and if that doesn't do it, then change the 35Z5 and see if the problem goes away.NostalgiaRadioTime — 12:28 AM
B&K 1077B no video
Hello Tim, I have that exact unit in my shop too plus a Sencore unit there are times I like one or other !!. Sincerely...radiorich — 11:07 PM
RCA 15X
Everthing goes at once, maybe it's the cold weather, I have had 2 dial strings break and no my little RCA is having dial...Paul Philco322 — 10:26 PM
Philco 91 Schematic
Hi Dan, I can't explain this specific resistor but I have seen the use of a switch to apply B+ voltage to screen gri...RodB — 09:36 PM
6TPZ and 5TPO Radio Help
I suspect it's been repaired before. And I suspect whoever repaired it, wanted to re-use old transistors' pin stubs in o...morzh — 09:24 PM
B&K 1077B no video
Thanks Rich! I'll take a look and see what he has. I know there's more modern equipment to be had, but this one I know a...TV MAN — 09:11 PM

[-]
Who's Online
There are currently 9856 online users. [Complete List]
» 2 Member(s) | 9854 Guest(s)
AvatarAvatar

>
  1. The PHILCO Phorum
  2. Philco Radio Discussions
  3. Philco Electronic Restoration