Need some direction on a grrreat little Philco PT-30. I changed out all capacitors, dialetric caps, and some worn looking resistors. I checked all the tubes and all test good. I used my meter to check for ground on the outside tube shields to chassi on the three of the five that are wired for it, all good. The audio sounds badly garbled, like a motor boat. The volume does goes up and down. Loud and strong. The lamp lights up bright when I turn it on then goes to a real low dim. I know this is normal but it is real dim when it finaly settles. New power cord also. SO what next? Any direction is helpfull. Can it still be a bad tube? I feel it is a ground issue, is there a way of checking each tube base? IF so which tube first? I get channels in fine. Is there a trick I am missing? Will send pics if interested and help. thank you for your help. Napi
Posts: 236
Threads: 30
Joined: Sep 2005
City: Minneapolis/St. Paul MN
Napijoe,
First thing to look into would be the alignment of the IF circuitry. If you're not sure how to do this, check back in...there's plenty of knowledgeable folks here more than willing to talk you through it. Best of luck!
Bill
Sent from my Pentium II on the AT&T Dial Network
I got some time tonight on this troubled radio and I discovered that it works great without its loop antenna!! The jumper wire I used to connect the tuning condenser to the loop antenna fell off and suddenly the audio became clear along with being able to get many channels. SO what does that mean?
There are two wires coming off of the loop antenna(obviously). I believe one goes to the top of the tuning condenser and the other goes to a wax covered coil next to the tuning condenser. At least that was the way it was setup when I got it. This wax covered coil is grounded to the chassie through a capacitor. Every time I connect the loop ant. to the top of the tuning condenser it blows the whole thing out of wack again. I switched the wires around and I get the same thing. Every time I try to connect to the tuning condenser it messes it up. It doesnt happen when I connect to the wax covered coil. Is this a tuning issue or a ground I am missing on the loop antenna? Maybe the tuning condenser? Has anyone heard of a loop antenna messing up a working radio? IF so what was the problem? Should I just attach a long wire to act as an antenna to the top of the tunning condenser and call it a day? I really was trying to not do that and run the radio as it was intended and utilize the cool intacted antenna inside the radio case. Thanks for your help, it really looks good and starting to come together.
Posts: 236
Threads: 30
Joined: Sep 2005
City: Minneapolis/St. Paul MN
One thing to check is that you have all the CORRECT tubes. If you have a wrong tube in there, especially the 7B7 or the 7C8, it might result in the condition you're experiencing. Also, a bad tube might do the same thing. Check to make sure the tubes are correct and good. Keep us posted.
Bill
Sent from my Pentium II on the AT&T Dial Network
So I tested the two above mentioned tubes and they test fine. I let the 7B8 warm up good in the tester because it never seems to get even warm as the others do. It does light up though. Anyway, THE RADIO works!!!! I don't know why now but the radio works.!! I soldered the antenna to its posts after I cleaned the wire off and it works great! had it on for hours last night on the oldies channel 1240 wbkz and worked like a dream. Sounded great, better than my new boombox on AM. Must be the tubes. Anyway, I am a** - suming that I must of rattled the 7B8 tube clean or that a solid soder joint works better than an aligator clip. If you would like I can send you pic if interested. I cannot believe it is the same radio. I have before and after pics. I cleaned up the bakolite and did a complete overhaul on the caps. The case is cracked in the lower right in the back but I consider it part of the charm. Sounds and looks great. SO excited. Thanks for you help. I am starting on my next radio this weekend and sure I will be back for more info. thanks again. joe
Posts: 225
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Joined: Oct 2005
City: Grand Blanc, Michigan
Stranger things have happened, I have a Philco 46-1209 console and one of the loctals had tape squares on the rivet heads and one had fallen off. It didn't make sense why the tape squares were on the rivets but they looked original so when I cut a new piece to replace the one that had fallen off the radio played fine, with the piece off the quality was shakey or poor at best. Sometimes it may not make sense but if it works, enjoy.
Posts: 236
Threads: 30
Joined: Sep 2005
City: Minneapolis/St. Paul MN
Joe,
Glad to see everything turned out well. Sounds like you may have cleared up, or cleaned up, an intermittent connection causing the oscillation. Good job!
49stude63 is right...stranger things have happened, but now it works. Time to head over to Old Ron's Bar & Grille. 8)
Bill
Sent from my Pentium II on the AT&T Dial Network
