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: 1 Guest(s)
[-]
Recent Posts
Value of capacitor
If this helps you sort it out just remember 10,000 mmfd or pf = .01 mfd. So 5,000mmfd = .005 mfd.Radioroslyn — 04:23 PM
Value of capacitor
OP here- the parts list calls for an .005 1000 volt mica. It currently has an .005 1000 volt electrolytic that is at lea...bridkarl — 02:09 PM
Value of capacitor
Maybe it's one of those paper caps that is wrapped in a mica-lookiing case.RodB — 01:51 PM
Value of capacitor
I also was wondering what the post about using polarized caps had to do with the subject? The cap is 5nF, does not exis...morzh — 10:22 AM
Value of capacitor
The OP stated that there is an electrolytic in the circuit in place of the coupling cap and wondered what effect it has....RodB — 09:53 AM
Value of capacitor
According to AI... ...assuming the electrolytic that's in it now is polarized... What does your response have to ...DaleHCook — 08:17 AM
Philco 50-925 antenna connections
Most loop antenna setups are either one continuous loop with two connections or 2 loops with 4 connections. The latter c...RodB — 02:16 PM
Value of capacitor
Not trying to answer for the OP, just commenting on the thread. According to AI... ...assuming the electrolytic that'...HowardWoodard — 02:09 PM
Philco 50-925 antenna connections
Hello Keith! I've updated your thread with the proper model number. Take care, - GaryGarySP — 01:10 PM
Value of capacitor
Why are you having to replace it? Does it measure out of tolerance? Is it mechanically damaged?DaleHCook — 07:50 AM

[-]
Who's Online
There are currently 2587 online users. [Complete List]
» 4 Member(s) | 2583 Guest(s)
AvatarAvatarAvatarAvatar

>