Hi All;
My philco 45 goes from working to being (Sound Wise) Dead, in about a minute after it starts to emit Sound from the Speaker..
And, yes I am using my Variac..
It emits a Pop! then after that there is no sound at all..
The Electrolytics have been replaced..
I have replace the tubes and that doesn't change anything, I am next going to take out the two Caps that are in Parallel with the primary winding on the Transformer and after that Take out the Tone Control, thinking that one of its Caps could be Bad, or leaking..
What does everyone think, Should I consentrate on, checking and replacing Capacitors or does it make more sense to go the Resistor Route..
All of the underside of the Chassis looks Pristine, no cob webs, no dead anything.. Nothing looks burnt or smells funny..
Even the Speaker looks like its been Reconed..
http://www.nostalgiaair.org/Resources/582/M0013582.htm
THANK YOU marty
Definitely replace ALL the paper capacitors. Cheap enough and easy to replace all the carbon resistors at the same time. All these components are no longer trustworthy. The tubes, however, may be just fine.
Hi All;
CodeFox, yes I plan on Replacing all of the Paper Caps.. But, I am hoping to learn something from this problem..
Yes, I can go in and blindly Replace All of the Capacitors and All of the Resistors..
And have learned nothing at all except that replacing everything maybe fixed the problem..
I hope to find out that this particular Capacitor or Resistor caused this particular problem.. I most likely won't seee this problem again, but someone else in the future might, and I will know what to look for and How to respond, to them..
THANK YOU Marty
Marty
You should've replaced all of them without trying to learn anything.
It is likely a cap that breaks down, maybe an interstage in the audio, say between the detector and the output amp.
or maybe a decoupling one.
But if you keep experimenting like this you may potentially lose your rectifier or a filter choke or a field coil...God know.
yes you do learn things by finding bad parts but the practice of replacing questionable parts in advance to me is unbeatable in the first place.
Hi All;
Thank You Both for Your Input..
Morzh, I see what you are saying, And I know that in one of the other Forums that there was a big argument about, replacing everything, Against one part at a time..
My only argument is that when I first got my Philco 34, I did that (replace everything) and it hasn't worked right since.. And I am too new at this to spot problems that I may put in by doing a full replace everything..
Now, maybe I can do a comprise of sorts, and do sections at a time, such as there is eight caps in the Audio sections and I could do them all at once or do the Paper Caps first and then the Mica's..
I guess, I am some what afraid, since I screwed up the Philco 34 and since this one (Philco 45) at least somewhat worked from the git go.. And I don't want to go from somewhat working to not working at all..
Iv'e decided to do the Four Paper caps in the Audio Section and then the four Mica caps..
THANK YOU marty
I don't think you need to replace the mica caps unless you find a problem with them. They say you should usually leave the mica caps alone, barring any problems. You can check them with a capacitor checker to be sure they are good. Just change the wax/paper caps.
Like Warren said, don't touch the micas - they have the presumption of innocence unlike the other parts.
try the cap #38, and then 39 if you choose to do it one by one.
Oh...and another question: does this happen in ALL the tone control positions? Make sure it is all of them, or maybe one of the tone control caps (#43) is bad.
Hi All;
Thank You Warren and Morzh for Your added input.. Ok, On the Mica Caps..
Morzh, Just after I took out C 61, and tried it which helped quite a bit, but when I move the chassis arround from bottom side up to top side up, it did the same thing.. I took out the wire for the Tone control completely eliminating C 43..
C 39 is in the line to being done, C 38 is a Mica Cap.. C 54 Volume Control Tap is done.. C 41 is done.. C 49 is being done and C51 is coming up..
THANK YOU marty
Hi All;
I was going to say that replacing one of the above mentioned caps did it.. But, It just went out !!!
So I have four other Paper Caps to go on the other side of the chassis and another Bakelite with two caps in it, yet to do..
I had turned it over awhile before it went out and the poping when it went was not as loud..
THANK YOU Marty
Hi All;
Nope, all the Papers are done, I have the Bakelite to do, but it will be later.. It also now squeels when I turn up the Volume, I don't know if this is related.. It still also pops.. And then no sound..
THANK YOU Marty
Hi All;
I got rid of the squeel, I wired back in the Tone Control.. But, it still pops.. And then of course no sound..
I am going to replace C 38 and C 50, 220 PF and C 34 and C 35, a 120 PF Capacitors..
THANK YOU marty
Marty
You could do yourself a big favor and when the "pop goes the Philco" again, touch the grid cap of the detector tube or the grid of the output tube (careful) and see if you hear the buzz. This will explain a lot.
PS. #38 is mica but it is highly a suspect, this is why I pointed it first.
Marty, it might be time to do a little diagnostics now. Hoping you cleaned tube pins and sockets. I would hook my volt meter to the plate of the output tube and see what you can see about the B+ when the radio dies. This should tell you if your problem is in the main rail something like the field coil or the output xformer primary.
Schematic link attached, Jerry
http://www.nostalgiaair.org/PagesByModel...013582.pdf
"Morzh, Just after I took out C 61, and tried it which helped quite a bit, but when I move the chassis arround from bottom side up to top side up, it did the same thing.."
Marty, this sounds like it could be a mechanical thing. Perhaps one of the tubes has a sagging element, or foreign matter in the base. Could also be foreign matter caught between socket pins. I've had things like that drive me insane, usually my own fault. Something like a trimmed wire, a blob of solder, a star washer that had fallen off where one of the bakelites was. Careful visual inspection is just as important as electronic troubleshooting.
Also highly likely BAD! I always seem to lose at least one of those star washers and generally a good shaking of the chassis and a blast of air from my compressor ultimately finds them (I hope).
Jerry