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

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

Philco 91 Restore Code ??
#46

Because the usable power rating of it then is (3,200/20,000)*25W= 4W.
Maybe a tad more due to the mass, but not much. You are not using the full resistor.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#47

I wondered about that. Wish there was some place local to get this stuff.
#48

The shadow meter in the radio is responding to tuned signals but it never goes to a very small shadow even on strong signals. Best I can get is about a 3/8 of an inch. Is that about right or should it get narrower? The 1k resistor (#14) has been replaced. Would altering the value of #14 make any difference if so higher or lower?

Also I can't get he lower end of the dial completely lined up. Off about 10kc. The low frequency compensator (#23) is turned out to where it is no longer making a difference. There is a 410pf mica (#24) across the compensator. Could that be a problem and maybe replace it with a different value. The dial is reading higher than the 10kc higher than it should. The high side is spot on.

Thanks,
Dan
#49

410pF is a large capacitance to parallel to a compensator.

As for the shadowmeter....yes, 3/8" is a bit wide, but then it also depends on the station's strength.
Does it go narrower than that when fed a signal from a generator?

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#50

The width does not get narrower with generator.

I think I will try some other cap values.
#51

If it does not get narrower with strong signal and your AVC is OK, it could veru well be that the shadowgraph's magnet is a bit weak. Not the end of the world, not even that important: I tune by ear and the shadowgraph is for show and tell mostly.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#52

How do I know if AVC is OK?

For the compensator cap I settled on 330pf. Its much closer now and close enough for me. I tried lower and higher values but lost gain with them. The original cap measured 296pf with my CCC meter. New Fluke 115 is on the way.




Users browsing this thread: 4 Guest(s)
[-]
Recent Posts
6TPZ and 5TPO Radio Help
This is the replacement guide for transistors by GE parts. So, GE-3 is your power replacement for AR14 Just ...morzh — 04:57 PM
Philco 91 Restore Code ??
How do I know if AVC is OK? For the compensator cap I settled on 330pf. Its much closer now and close enough for me. I ...dconant — 04:46 PM
6TPZ and 5TPO Radio Help
If the small signal ones, take any Ge transistor with unity gain good enough and Vce max 30 or so V. For the output....y...morzh — 03:43 PM
The list of my radio & TV collection!
Yes, Michael. This winter I repaired this Westinghouse, RCA 121 and Zenit 5S29. All that remains is to veneer the Zenit ...RadioSvit — 03:28 PM
6TPZ and 5TPO Radio Help
Thank you. I have one board completely de-populated. Just looking for the correct values. I'll let you know. Still h...R3Sons — 03:13 PM
The list of my radio & TV collection!
Is this the one from the Fall Kutztown 2023?morzh — 02:59 PM
Philco 91 Restore Code ??
If it does not get narrower with strong signal and your AVC is OK, it could veru well be that the shadowgraph's magnet i...morzh — 02:58 PM
Philco 91 Restore Code ??
The width does not get narrower with generator. I think I will try some other cap values.dconant — 02:56 PM
Philco 91 Restore Code ??
410pF is a large capacitance to parallel to a compensator. As for the shadowmeter....yes, 3/8" is a bit wide, bu...morzh — 02:49 PM
The list of my radio & TV collection!
My new nostalgic video... My weekly video on radio history Who is interested - come, watch, critically evaluate the qu...RadioSvit — 01:47 PM

[-]
Who's Online
There are currently 3666 online users. [Complete List]
» 2 Member(s) | 3664 Guest(s)
AvatarAvatar

>