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

Philco 90 question
#1

I have a 90 chassis, the one with a single '47 output tube. I've been recapping this thing, and it's coming along pretty well, but there's one odd thing that I've noticed.

I keep having trouble with the '24 IF amp. Every once in a while it dies until I tap on it (the original one had an intermittent short in it, if it died and I tapped on it, it would come back, but I could see it arcing inside). What is interesting is, when the tube dies, or when I remove it completely, I can still hear the tuned in station in the speaker, although the volume control has no effect. I've tracked the signal paths and I find that all the bypass caps in the signal paths have already been replaced.

Both of the shields are missing. I have fashioned a shield around the IF amp, which seems to be very touchy, and breaks into oscillation at the drop of a hat, and this cleared up the oscillations.

Is it possible that I am going to have to locate the original shields in order to keep this 'ghost' signal out? I would not worry too much about it, but I'm thinking it may be out of phase and therefor cancelling some of the signal.

TIA
#2

Someone here once mentioned someone else who makes shields for Philcos. Pretty close looking to those original ones.


Are you saying that the shield makes the IF work normally and it no longer dies? Or you just mixed the two together?
#3

The tube still dies on occasion, it just no longer throws the radio into oscillation. Time to order some more '24's.

Don't suppose you remember who it was that makes those shields?
#4

The gentleman's name is Chuck Paci; he may be reached at cpaci1 at verizon dot net. He does not make the round shields, but he does make the large shields that fit over multiple tubes in Philco 70, 90, 112 and a few others.

--
Ron Ramirez
Ferdinand IN
#5

Thanks, Ron. I'll contact him. Those are the ones I'm looking for.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
Yes, 57 is an electrolytic cap that should be 12 mfd 400 volts according to the parts list from the Phorum library schem...RodB — 06:01 PM
Philco 42-345 Restoration/Repair
Looks like if I am reading it correctly it looks like the silver capacitor#57 that appears to be a replacement is of a l...osanders0311 — 05:09 PM
Philco model 38 code 121 not receiving signal.
Thanks Arran. Yeah this plastic is pretty thin. It's a little thinner than the original stuff. It kinda reminds me of p...Stormlord5500 — 04:37 PM
Testing a speaker and output transformer Trutone A2-G
The equivalent of one short turn is basically the same as that of a shorted load. If it is the primary's turn, then the ...morzh — 03:53 PM
Testing a speaker and output transformer Trutone A2-G
I've never had an output transformer become shorted, the failure mode is usually an open primary, or in a center tapped ...Arran — 03:52 PM
Philco model 38 code 121 not receiving signal.
As long as the plastic sheeting isn't too thick, I think that the thickness of photographic film would be just about rig...Arran — 03:19 PM
Philco model 38 code 121 not receiving signal.
Well why not! :lol:Stormlord5500 — 03:14 PM
Philco model 38 code 121 not receiving signal.
Good luck next thing you know you will be winding coils just for the fun of it. DavidDavid — 11:29 AM
Testing a speaker and output transformer Trutone A2-G
morzh Short-circuited turns can be considered as a half-dead transformer. But on this case transformer will hot and s...Vlad95 — 11:01 AM
Testing a speaker and output transformer Trutone A2-G
I am not sure how a transformer could be weak. It could be inadequate, but only when you replace the original with somet...morzh — 09:56 AM

[-]
Who's Online
There are currently 2143 online users. [Complete List]
» 1 Member(s) | 2142 Guest(s)
Avatar

>